U.S. Fish & Wildlife Service Emblem
U.S. Fish & Wildlife Service
Analytical Control Facility
A Branch of Ecological Services

Contents:
Who We Are
Services We Provide
Staff & Who to
Contact
Contract
Laboratories
How we assign Labs
Quality Control
Inorganic Lab
Statement of Work
Organic Lab
Statement of Work
Catalog Information
Pricing Guides
Analytical Methods
Contaminant Database

How to Use the Pricing Guides

 
Home
 
Links:
DOI Home Page
USFWS Home Page
DEQ Home Page
Contact us at: chemistry@fws.gov
Privacy & Disclaimer
FOIA
 

Environmental Trace Substance Laboratory (ETSL) Labratory Methods

Select one of the links blelow to display the method descriptions associated with ETSL.

Method Code

Method Title

001

PRECONCENTRATION OF ICP - PH6

002

PRECONCENTRATION OF ICP - PH3

003

NITRIC - PERCHOLORIC DIGESTION - (I.C.P.)

004

INDUCTIVELY COUPLED PLASMA (ICP)

005

% MOISTURE

006

HOMOGENIZATION

007

NITRIC - PERCHOLORIC DIGESTION - (SELENIUM)

008

NITRIC - PERCHOLORIC DIGESTION - (ARSENIC)

009

ARSENIC AND SELENIUM BY HYDRIDE

010

ARSENIC IN FISH AND MARINE SAMPLES BY HYDRIDE

011

NITRIC REFLUX DIGESTION FOR MERCURY

012

MERCURY - COLD VAPOR ATOMIC ABSORPTION

013

NITRIC DIGESTION FOR GRAPHITE FURNACE

014

GRAPHITE FURNACE AA

015

TOTAL VOLATILE SOLIDS (TVS)

016

ANTIMONY BY HYDRIDE

017

NITRIC - PERCHOLORIC DIGESTION - (ANTIMONY)

018

TOTAL ORGANIC CARBON ANALYSIS (SOIL AND SEDIMENT)

019

GRAIN SIZE DETERMINATION

020

Microwave Digestion

021

Magnesium Nitrate Prep.

022

HCl04-HF Digestion for Sediments

023

Microwave Digestion Which Is Aliquoted and Has HCl Added To The Aliquot For Mercury Analysis.

024

Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)

025

GRAPHITE FURNACE AND ICP SOIL DIGESTION

026

Residue, Filterable (Gravimetric, Dried at 180-C)

027

Residue, Non-Filterable (Gravimetric, Dried at 103 - 105-C)

028

 

029

Determination of Acid Volatile Sulfide in Sediments

030

Total Cyanide Detection from Water Samples

 

 

 

 

 

Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 001

PRECONCENTRATION OF ICP - PH6

A 30 g. sample of the digestate for I.C.P. was weighed into a 50 ml. screw top centrifuge tube. One ml. of 2000 ppm Indium and 1 ml. of 10% ammonium acetate buffer were added and the pH adjusted to 6.5 with high purity NH4OH from Seastar. One ml. of a 10% DDTC was added and the caps screwed on and mixed by turning end over end 6 times slowly. After mixing, the tubes were centrifuged in an I.E.C. refrigerated centrifuge at 20 C for 15 minutes at 15,000 RPM. The liquid was then decanted from the precipitate and 0.3 ml. of high purity HNO3 from Seastar was added. The tubes were heated in a water bath at 95oC to dissolve the precipitate and diluted to 3 ml. with deionized water.

For samples high in Calcium and Phosphate a pH of 6.0 was used to reduce the precipitation of Ca3(PO4)2.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 002

PRECONCENTRATION OF ICP - PH3

A 30 g. sample of the digestate for I.C.P. was weighed into a 50 ml. screw top centrifuge tube. One ml. of 2000 ppm Indium and 1 ml. of 10% ammonium acetate buffer were added and the pH adjusted to 3.0 with high purity NH4OH from Seastar. One ml. of 10% APCD was added and the caps screwed on and mixed by turning end over end 6 time slowly. After mixing, the tubes were centrifuged in an I.E.C. refrigerated centrifuge at 20oC for 15 minutes at 15,000 RPM. The liquid was then decanted from the precipitate and 0.3 ml. of high purity HNO3 from Seastar was added. The tubes were heated in a water bath at 95 C to dissolve the precipitate and diluted to 3 ml. with deionized water.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 003

NITRIC - PERCHOLORIC DIGESTION - (I.C.P.)

Approximately 0.5 g. of sample was weighed into a freshly cleaned 100 ml. quartz Kjeldahl flask. (Samples containing a high percent of silica and sediment samples were digested in 100 ml. teflon beakers.) For water samples, 50 ml. of sample was measured into a teflon beaker. Slowly 15 ml. of concentrated sub- boiled HNO3 and 2.5 ml. of concentrated sub- boiled HC104 were added. Foaming may occur with some samples. If the foaming started to become excessive, the container was cooled in a beaker of cold water. After the initial reaction had subsided, the sample was placed on low heat until the evolution of dark red fumes has ceased. Gradually, the heat was increased until the HNO3 began refluxing; samples were allowed to reflux overnight. (This decreased the chance for charring during the reaction with HC104.) After the refluxing, the heat was gradually increased until the HNO3 had been driven off, and the reaction with HC104 had occurred. When dense white fumes from the HC104 were evident, the samples were removed from the heat and allowed to cool. Two ml. of concentrated sub-boiled HCl was added. The flasks were replaced on the heat and warmed until the containers were hot to the touch or started to boil. They were removed from the heat, and 5-10 ml. of deionized water was added. Samples were allowed to cool. They were then diluted using deionized water in a 50 ml. volumetric flask and transferred to a clean, labeled, 2 oz. polyethylene bottle.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 004

INDUCTIVELY COUPLED PLASMA (ICP)

The instrument used for ICP analysis was a Jarrell-Ash Model 1100 Mark III with 40 analytical channels, controlled by a Digital Equipment Company (DEC) 11/23+ computer with two RLO2 disk drives, DEC VT100 terminal, and DEC LA120 Decwriter III. The instrument was standardized with a series of seven standards containing 36 elements. After the standardization, the detection limit was determined by taking ten integrations of the zero standard; three times the standard deviation of the mean was used as the detection limit. Instrumental quality control samples were then analyzed to check the ICP operation. If the values were acceptable, the samples were then analyzed. Standards were run every 10-15 samples to check for drift. If the drift was more than 5%, the instrument was restandardized. After the analysis was completed, the data was transferred to the Perkin-Elmer LIMS 2000 computer for calculation. The final detection limit for each element was further increased by 4% of the magnitude of the spectral interferences from the other elements. The data was checked before calculation to correct for possible errors in sample number, weight, volumes and dilution. The data was calculated using the ICP calculation program written by ETSRC computer staff, which corrected for blanks, standard drift, spectral interferences, sample weight, sample volume, and dilution. After quality control was reviewed, a final report was generated using a Hewlett Packard laser jet printer.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 005

% MOISTURE

For animal tissue and sediments of sufficient size, moisture was determined by placing a weighed aliquot of the sample in a Fisher Isotemp oven and drying at 103 - 105 C. The dried sample was then weighed and the data entered into a computer program to generate the % moisture and final report.

Plants, and samples to small for oven dried moisture determination had the % moisture calculated from the moisture lost during the freeze-drying in the Labcono Freeze-Dryer 8. The data was entered into a computer program to generate a % moisture and final report.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 006

HOMOGENIZATION

Large tissue samples, such as whole fish, were first run through a meat grinder one or more times depending on the size of the sample. An aliquot of the ground sample was weighed and frozen. For smaller tissue samples and plant samples the entire sample was weighed and then frozen. For sediments, the sample was mixed and an aliquot weighed and frozen. The frozen samples were placed in a Labcono Freeze Dryer 8 until the moisture had been removed. The dry samples were then weighed and further homogenized using a blender, or Spex Industries, Inc. Model 8000 mixer/mill with tungsten-carbide vial and balls.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 007

NITRIC - PERCHOLORIC DIGESTION - (SELENIUM)

Approximately 0.5 g. of sample was weighed into a freshly cleaned 100 ml. quartz Kjeldahl flask. (Samples containing a high percent of silica and sediment samples were digested in 100 ml. teflon beakers.) For water samples, 50 ml. of sample was measured into a teflon beaker. Slowly 15 ml. of concentrated sub- boiled HNO3 and 2.5 ml. of concentrated sub- boiled HC104 were added. Foaming may occur with some samples. If the foaming started to become excessive, the container was cooled in a beaker of cold water. After the initial reaction had subsided, the sample was placed on low heat until the evolution of dark red fumes had ceased. Gradually, the heat was increased until the HNO3 began refluxing; samples were allowed to reflux overnight. (This decreased the chance for charring during the reaction with HC104.) After the refluxing, the heat was gradually increased until the HNO3 had been driven off, and the reaction with HC104 had occurred. When dense white fumes from the HC104 were evident, the samples were removed from the heat and allowed to cool. Two ml. of concentrated sub-boiled HCl was added. The flasks were replaced on the heat and warmed until the containers were hot to the touch or started to boil. They were removed from the heat, and 5-10 ml. of deionized water was added. Samples were allowed to cool. They were then diluted using deionized water in a 50 ml. volumetric flask and transferred to a clean, labeled, 2 oz. polyethylene bottle.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 008

NITRIC - PERCHOLORIC DIGESTION - (ARSENIC)

Approximately 0.5 g. of sample was weighed into a freshly cleaned 100 ml. Kjeldahl flask. (Samples containing a high percent of silica and sediment samples were digested in 100 ml. teflon beakers.) For water samples, 50 ml. of sample was measured into a teflon beaker. Slowly 15 ml. of concentrated sub-boiled HNO3 and 2.5 ml. of concentrated sub-boiled HC104 were added. Foaming may occur with some samples. If the foaming started to become excessive, the container was cooled in a beaker of cold water. After the initial reaction had subsided, the sample was placed on low heat until the evolution of dark red fumes had ceased. Gradually, the heat was increased until the HNO3 had been driven off, and the reaction with HC104 were evident. The samples were removed from the heat and allowed to cool. Samples were diluted using deionized water in 50 ml. volumetric flasks and transferred to clean, labeled, 2 oz. polyethylene bottles.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 009

ARSENIC AND SELENIUM BY HYDRIDE

The Varian VGA-76 hydride generation accessory was mounted on either a Perkin-Elmer Model 603 AA or Model 3030 (B) AA. Electrodele ss Discharge lamps (EDL) were used. The instrument and EDL settings were taken from the instrument manuals. The burner mount for a Perkin-Elmer Model 10 Hydride generator was modified slightly to hold the Varian quartz cell. The cell was aligned in the light path of the burner chamber and a very lean flame was used for heating the cell. The two stoc solutions were 50% v/v sub-boiled HCl and 0.6% NaBH4 in 0.5% NaOH for Selenium and concentrated sub-boiled HCl and 1% NaBH4 in 0.5% NaOH for Arsenic. Samples were diluted in 10% v/v sub-boiled HCl. Standards were prepared by dilution of Fisher 1000 ppm stock in 10% v/v sub-boiled HCl in the range of 0 to 20 PPB. The instrument was standardized to read directly in PPB using S1 = 5.00 and S2 = 20.00. After standardization, the standardization was checked by reading other standards such as 2.00,10.00 and 15.00 PPB and an instrumental quality control sample with a known value. If the standards and quality control were acceptable, the detection limit was determined by reading the zero standard 10 times and twice the standard deviation of the mean was used as the detection limit. Samples were analyzed by taking an integrated reading for 3 seconds after the plateau was reached for the sample. This occurred approximately 45 seconds after the sample tube was placed in the sample. Standardization was checked every 8-15 samples and approximately 10% of the samples were checked by the method of additions to monitor matrix effects. Matrix effects were usually not significant with the VGA-76. The data was corrected for drift of the standard curve and entered into the AA calculation program. This program corrected for blank, dilution, sample weight, sample volume and recorded the data in the LIMS database for report generation.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 010

ARSENIC IN FISH AND MARINE SAMPLES BY HYDRIDE

The Perkin-Elmer MHS-1 hydride generation accessory was mounted on either a Perkin-Elmer Model 603 AA or Model 3030 (B) AA. An Electrodeless Discharge Lamp (EDL) was used. The instrument and EDL settings were taken from the instrument manuals. The cell was aligned in the light path of the burner chamber and a very lean flame used for heating the cell. The standard curve was run and a quality control sample of known concentration to check the standard curve. Blanks and samples are run by diluting an aliquot of the digested sample to 10 ml. with 4% v/v HC104. The amount of sample used varied with the Arsenic concentration. Samples were analyzed using the Method of Standard Additions. The peaks from the recorder tracing were measured with a ruler and the slope and intercept calculated on a calculator. The data was entered into the AA calculation program. This program corrected for the blank, dilution factors, sample weight, sample volume and recorded the data in the LIMS database for report generation.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 011

NITRIC REFLUX DIGESTION FOR MERCURY

Approximately 0.5 g. of sample was weighed into a freshly cleaned 50 ml. round bottom flask with 24/40 ground glass neck. For waters, 10 ml. of sample was measured into the flask. Five ml. of concentrated sub-boiled HNO3 was added and the flask was placed under a 12 inch water cooled condenser with water running through the condenser. The heat was turned up to allow the HNO3 to reflux no more than 1/3 the height of the columns. Samples were allowed to reflux for two hours. Then the heat was turned off and the sample allowed to cool. The condensers were rinsed with 1% v/v HCl and the flasks removed. The samples were diluted with 1% v/v HCl in a 50 ml. volumetric flask and then transferred to a clean, labeled, 2 oz. flint glass bottle.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 012

MERCURY - COLD VAPOR ATOMIC ABSORPTION

Equipment used for Cold Vapor Atomic Absorption include: Perkin-Elmer Model 403 AA; Perkin- Elmer Model 056 Recorder; Technicon Sampler I; Technicon Pump II; a glass cell with quartz windows and capillary tube for entry and exit of the mercury vapor; and a liquid-gas separator. The samples were placed in 4 ml. sample cups at least 3/4 full. The samples were mixed with hydroxylamine for preliminary reduction, then stannous chloride for reduction to the mercury vapor. The vapor was separated from the liquid and passed through the cell mounted in the light path of the burner compartment. The peaks were recorded and the peak heights measured. The standardization was done with at least 5 standards in the range of 0 to 10 ppb. The correlation coefficient was usually 0.9999 or better and must have been at least 0.999 to have been acceptable. A standard was run every 8-10 samples to check for drift in the standardization. This was usually less than 5%. Standards were preserved with 10% v/v HNO3, 1% v/v HCl and 0.05% w/v K2Cr207. The solution concentrations were calculated and the data entered into the AA calculation program which corrected for blank, dilution, sample weight, sample volume and entered the data into the LIMS system for report generation.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 013

NITRIC DIGESTION FOR GRAPHITE FURNACE

Approximately 0.5 g. of sample was weighed into a freshly cleaned 100 ml. Kjeldahl flask (samples containing a high percent of silica and sediment samples were digested in 100 ml. teflon beakers). For water samples, 50 ml. of sample were measured into a teflon beaker. Slowly, 15 ml. of sub-broiled HN03 were added. Foaming may occur with some samples. If the foaming started to become excessive, the flask was cooled in a beaker of cold water. The samples were placed on low heat until the initial reaction and evolution of dark red fumes had ceased. Gradually, the heat was increased until the volume was reduced to approximately 2 ml. The sample was removed from the heat and allowed to cool. Samples were diluted using deionized water in a 50 ml. volumetric flask and transferred to a clean, labeled, 2 oz. polyethylene bottle.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 014

GRAPHITE FURNACE AA

The instruments used for graphite furnace AA, were either a Perkin-Elmer Model 3030B with Model HGA-500 graphite furnace, Model AS-40 autosampler and Model 056 recorder, or the Perkin-Elmer Model 5100 with Model HGA-600 graphite furnace, Model AS- 60 autosampler and Model 7300 computer. The conditions for a particular element were set up according to the instruction manual. The L'vov platform and appropriate matrix modifier were used. A standard curve and known quality control sample were run to check the instrument operation. The Method of Standard Additions was used on a minimum of 1 out of 5 samples. If the average slopes for the standard additions gave a %RSD of 5% or less then the average slope was used to calculate the sample concentrations. If the average slope was not acceptable then the sample all had to be run using the Method of Standard Additions. After calculating the solution concentration, the data were entered into a computer program that corrected for blank, dilution, sample weight and volume, and entered the data into the LIMS data base for report generation.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 015

TOTAL VOLATILE SOLIDS (TVS)

Aliquots of oven-dried samples were weighed into previously fired crucibles. The crucibles with samples were then placed in an oven and fired at 550øC for a minimum of 4 hours. The crucibles were allowed to partially cool and then were placed in a desiccator until they cooled to room temperature and were weighed. The oven-dried weights and the weights of the samples after firing were entered into the computer and TVS was calculated. The formula used to calculate TVS follows.

Oven-dry Sample Weight - Fired Sample Weight
______________________________________ = TVS
Oven-dry Sample Weight

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 016

ANTIMONY BY HYDRIDE

The Varian VGA-76 hydride generation accessory was mounted on either a Perkin-Elmer Model 603 AA or Model 3030 (B) AA. Electrodeless Discharge Lamps (EDL) were used. The instrument and EDL settings were taken from the instrument manuals. The burner mount for a Perkin-Elmer Model 10 Hydride generator was modified slightly to hold the Varian quartz cell. The cell was aligned in the light path of the burner chamber and a very lean flame was used for heating the cell. The two stock solutions were concentrated sub-boiled HC1 and 0.6% NaBH4 in 0.5% NaOH. Samples were diluted with 50% v/v sub-boiled HC1, 1% w/v KI. Standards were prepared by dilution of Fisher 1000 ppm stock with 50% v/v sub-boiled HC1, 1% w/v KI, in the range of 0 to 20 PPB. The instrument was standardized to read directly in PPB using S1 = 5.00 and S2 = 20. After standardization, the standardization was checked by reading other standards such as 2.00, 10.00, and 15.00 PPB and an instrumental quality control sample with a known value. If the standards and quality control were acceptable, the detection limit was determined by reading the zero standard 10 times, and twice the standard deviation of the mean was used as the detection limit. Samples were analyzed by taking an integrated reading for 3 seconds after the plateau was reached for the sample. This occurred approximately 45 seconds after the sample tube was placed in the sample. Standardization was checked every 8-15 samples and approximately 10% of the samples were checked by the method of additions to monitor matrix effects. Matrix effects were usually not significant with the VGA-76. The data was corrected for drift of the standard curve and entered into the AA calculation program. This program corrected for blank, dilution, sample volume and recorded the data in the LIMS database for report generation.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 017

NITRIC - PERCHOLORIC DIGESTION - (ANTIMONY)

Approximately 0.5 g. of sample wa weighed into a freshly cleaned 100 ml. quartz Kjeldahl flask. (Sediment samples and samples containing a high percent of silica were digested in 100 ml. teflon breakers). For water samples, 50 ml. of sample were measured into a teflon beaker. Slowly, 15 ml. of concentrated sub-boiled HNO3 and 2.5 ml. of concentrated sub-boiled HC104 were added. Foaming may occur with some samples. If the foaming started to become excessive, the container was cooled in a beaker of cold water. After the initial reaction had subsided, the sample was placed on low heat until the evolution of dark red fumes had ceased. Gradually, the heat was increased until the HNO3 began refluxing, samples were allowed to reflux overnight. (This decreased the chance of charring during the reaction with HC104). After the refluxing, the heat was gradually increased until the HNO3 had been driven off, and the reaction with HC104 had occurred. When dense white fumes from the HC104 were evident, the samples were removed from the heat and allowed to cool. Fifteen ml. of concentrated sub-boiled HC1 were added. The flasks were replaced on the heat and warmed until the containers were hot to the touch or started to boil. They were removed from the heat, and 5-10 ml. of deionized water were added. Samples were allowed to cool. They were then diluted using deionized water in a 50 ml. volumetric flask and transferred to clean, labeled, 2 oz. polyethylene bottles.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 018

TOTAL ORGANIC CARBON ANALYSIS (SOIL AND SEDIMENT) DRY OXIDATION METHOD

The analyst will need to make three (3) replicates of each blank and each sample.

Label all of the ampules with a high temperature grease pencil before weighing. Break all ampules open, trying to get as little glass inside the ampules as possible. When not using, cover the ampules with aluminum foil to keep additional contaminants out of the ampules.

SAMPLE PREPARATION

Place ampule on pan of 5 place balance, tare to zero, add the desired mass of sample (usually 3-5mg), record the mass of the sample, put the ampule in the holding rack. Cover the ampule with aluminum foil. Start the same procedure with the next ampule.

Add 100 ul of 10% HCl solution to all of the sample and blank ampules. The fizzing that may be observed is the reaction between the HCl and any inorganic carbon in the sample.

Put the uncovered ampules into an oven and bake at 100 C for at least one (1) hour or however long it takes for sample to reach dryness.

Prepare a set of KHP stds. ranging from 25 ug to 250 ug C following the KHP std. prep method. These will be used to determine a std. curve for TOC values.

KHP STD. PREP.

2.126 grams of Potassium Hydrogen Phthalate is weighed then transferred to a 100 ml volumetric flask. The dilution to 100 mls is done with boiled D.I. H20. (The D.I. H20 is boiled to d rive off as much carbon as possible).

This reagent (which equals 10,000 ug/ml C) is further diluted to 500, 400, 300, 250, 200, 100 and 50 ug/ml C levels. One half ml (500 ul) pipet is then used to make the 250 thru 25 ug C stds.

Spikes are also made from the same reagent.

At least 4 ampules should be made of each std., and more depending on the total amount of analyses.

The stds. are dried at 100 C but usually take as long as 4 hrs. to dry because of their 1/2 ml liquid volume.

After all visible liquid has evaporated from samples and stds. remove the ampules from the drying oven and allow to cool.

When the ampules are cool, add one (1) dipper (200 mg) of the combusted cupric oxide to each ampule.

Purge each ampule with oxygen from the Purge & Seal Unit for 4 to 6 minutes and then seal.

The ampules can then be carefully placed in the muffle furnace and baked at 550 C for 4-5 hours.

Cool and then analyze using a non-dispersive infrared analyzer. (Oceanographic International Corp.)

ANALYSIS

Set up standard curve using the KHP stds. Three or four ampules are broken of each std. to get a good representative curve.

After the curve is established, begin analyzing the samples and determine their ugC according to this KHP curve.

Detection limit for a 4 mg (0.004 gm) sample is 0.1% or 1000 mcg/g dw.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 019

GRAIN SIZE DETERMINATION

Sieve an air dried, crushed sample. Place approximately 10 g of sample in a 500 ml Fleaker. Those samples with greater than 1.0% organic carbon (wet weight) need to be treated to remove organic matter. Add 10 mls deionized water, 10 mls 30% H2O2, and 1 drop acetic acid. Stir, cover and heat to approximately 60 C. Then add additional H2O2 in 5 ml increments at 15 minute intervals until organic matter is oxidized (no bubbling). If the reaction is too vigorous, slow with the addition of Dl water. After organic matter is removed, oven dry the samples (still in Fleakers) at 105 C. Weigh samples.

Add 10 mls sodium hexametaphosphate to each sample, and bring volume to approximately 150 mls with Dl water. A blank consisting of 10 mls sodium hexametaphosphate and 150 mls Dl water should also be made at this time. Put stoppers in the Fleakers and shake either for 4 hours of overnight (minimum 12 hours) on a horizontal reciprocating shaker (120 oscillations/minute).

Sieve samples through a 50 um sieve to remove sand fraction. Transfer the sand fraction that remains in the sieve to a weighing pan, oven-dry, cool in a desiccator and weigh. Arrange the fleakers for pipetting and bring volume to 400 mls with Dl water. Determine average temperature of the suspensions, and cover each Fleaker with a watch glass.

Remove watch glass from the first Fleaker, cap with a rubber stopper, and shake vigorously for approximately 10 seconds. Then shake end-over-end for 15 seconds. Remove rubber stopper and replace watch glass. Shake samples at approximately 2 minute intervals.

Pipet an aliquot at 5.0 cm below the surface within a 15- to 20-second interval, discharge into a weighing pan, rinse the pipet and add the rinse to the pan. Oven dry the aliquots, cool in a desiccator, then weigh. The correction factor for the weight of the sodium hexametaphosphate must be subtracted to obtain the weight of the clay.

Percentages of sand, silt and clay are then determined according to the following equations:

% sand = 100 (total sand weight/total soil weight)
% clay = (clay weight) (400/pipette volume) (100/total soil weight)
% silt = 100 x (% sand + % clay)

Table 1. Setting times at corresponding temperature for pipetting <2-um fraction at a 5-cm depth.

Temperature Setting Times

C
h: mm
17
4:22
18
4:15
19
4:09
20
4:03
21
3:57
22
3:51
23
3:46
24
3:41
25
3:36
26
3:31
27
3:26
28
3:22
29
3:17
30
3:13

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 020

Microwave Digestion

This procedure is used for samples of limited size. Preferably 0.5 g of dry sample is weighed directly into a clean tared teflon bomb. Then 5 mls of concentrated sub-boiled nitric acid (HNO3) and 3 mls of hydrogen peroxide (H202, 30% ACS Reagent) are added.

The bomb is capped and tightened at the capping station to 12 ft. lbs./in2. The bomb is then set overnight. After
12 or more hours, the accumulated gases are vented. The bombs are then placed in the teflon rack. Tubing is inserted into each bomb with the other end of the tubing going into the waste container in the center of the rack. The rack with bombs is then placed on the turntable in the microwave oven, and the door is closed. The fan and turntable are turned on. The pressure limit is set to 100. Then the microwave is programmed and started.

When samples are finished heating, they are allowed to cool to room temperature. The samples are diluted to 50 ml using deionized water or 1% HCl, depending on what elements were to be analyzed from this digestion. If samples were small, the volume of acid and hydrogen peroxide were adjusted, and the final volume was diluted to 25 ml.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 021

Magnesium Nitrate Prep.

Approximately 0.5 g of sample was weighed into an acid cleaned 100 ml glass beaker. The samples were wet with 3 mls of methanol. 5 drops of anti-foam agent, 10 mls of 40% (w/v) magnesium nitrate hexahydrate and 10 mls of nitric acid were then added.

Beakers were covered with watch glasses and refluxed on low (70-80 ) heat overnight (8-12 hrs.). The temperature was then increased to 200 C and the watch glasses slid to one side of beaker to speed evaporation and cook sample to complete dryness. This may take 8-12 hrs. Watch glasses were then repositioned and the samples allowed to cool.

Samples were then transferred to a cold muffle furnace. The temperature was started at 250 and ramped to 500 in 50 increments. Samples were left at each temperature for 15 minutes. Once temperature reached 500, the samples remained at that temperature for 3 hours.

Samples were cooled to room temperature. The 20 mls of 50% HCl were added. The watch glasses were replaced and samples were gently boiled on a hot plate for 1 hour. Samples are not allowed to go to dryness. If needed, more than 50% HCl was added to continue the boiling for 1 hour.

The sample was again cooled. The volume was readjusted to 20 mls with 50% HCl, then diluted to 100 mls with deionized water.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 022

HCl04-HF Digestion for Sediments

Approximately 1 gram of sample is weighed into a clean 100 ml teflon beaker and is then wet with 5 ml of distilled water.

Two ml of HCl04 (70%) and 12 ml of HF (40%) are added, and the sample is heated to near dryness.

An additional 8 ml of HF are then added and the sample heated to dryness.

Two ml of HCl04 and several ml of distilled water are again added to the sample and evaporated to dryness.

The remaining residue is dissolved in 8 ml of 1:1 HCl and 20 ml of water. The sample is then diluted to a final volume of 100 ml and stored in a 4 oz. polyethylene bottle.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 023

Microwave Digestion Which Is Aliquoted and Has HCl Added To The Aliquot For Mercury Analysis.

This procedure is used for samples of limited size. Preferably 0.5 g of dry sample is weighed directly into a clean tared teflon bomb. Then 5 mls of concentrated sub-boiled nitric acid (HNO3) and 3 mls of hydrogen peroxide (H202, 30% ACS Reagent) are added.

The bomb is capped and tightened at the capping station to 12 ft. lbs./in2. The bomb is then set overnight. After 12 or more hours, the accumulated gases are vented. The bombs are then placed in the teflon rack. Tubing is inserted into each bomb with the other end of the tubing going into the waste container in the center of the rack. The rack with bombs is then placed on the turntable in the microwave oven, and the door is closed. The fan and turntable are turned on. The pressure limit is set to 100. Then the microwave is programmed and started.

When samples are finished heating, they are allowed to cool to room temperature. The samples are diluted to 50 ml using deionized water. If samples were small, the volume of acid and hydrogen peroxide were adjusted, and the final volume was diluted to 25 ml.

Certain elements are adversely effected by HCl in the dilution. However, HCl is required when mercury is an analyte. In these cases, the microwave digestion is diluted with deionized water and no HCl. Then an aliquot is taken immediately, placed in a separate bottle and has concentrated HCl added. The size of the aliquot and the amount of HCl will vary depending on sample size and number of analytes. Sample weights and volumes are corrected for the
aliquoting and addition of HCl.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 024

Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)

The instrument used for ICP-MS analysis was a Perkin-Elmer model ELAN 5000. The instrument was standardized with t
wo multi-element standards. After the standardization, the detection limit was determined by taking ten measurements of the zero standard. Three times the standard deviation of the mean was used as the detection limit. An instrument quality control sample was then analyzed to check the ICP-MS operation. If the value was acceptable the samples were then analyzed. Standards were run every 10-20 samples to check for drift. If the drift was more than 10%, the instrument was restandardized. After the analysis was completed, the data was transferred to the Concurrent LIMS system for calculation. The data was checked before calculation to correct for possible errors in sample number, weight, volume and dilution. The data was calculated using the ICP-MS calculation program written by ETSRC computer staff, which corrected for blanks, instrument drift, sample weight, sample volume and dilution (1). After quality control was reviewed, a final report was generated.

(1) A spectral correction on Cr was performed for samples prepared in hydrochloric or perchloric acid. Due to the fact that V can not be measured in chlorine matrices with quadrupole based ICP-MS, the V spectral interference on Cr was corrected with the V value from ICP- OES. The reported Cr value was the Cr value from ICP-MS minus 5.6% of the V value from ICP-OES.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 025

GRAPHITE FURNACE AND ICP SOIL DIGESTION

SCOPE: Metals from sand, soil, or sediment.

PRINCIPLE: Dissolve sample in liquid so that it may be injected into analyses instrument.

EQUIPMENT: Face shield, teflon beakers, hot plate, 10 ml and 50 ml poly propylene centrifuge tubes.

REAGENTS: Concentrated nitric acid (HN03) (Baker instra-analyzed or better) concentrate hydrochloric acid (HCL) (Baker instra-analyzed or better) scandium 10.000 ppm

PROCEDURE:

1. Weigh 1.0 g of subsample into a teflon beaker
2. Add 20 ml of 3:1 hydrochloric:nitric
3. Place on hot plate and heat for 4 hours at a setting 1-2
4. After 4 hours, raise setting to 4-5 until approximately 11 mls of acid has evaporated (if the sample goes dry or starts to scorch it will need to be redone)
5. The sample is then filtered and transferred into a 50 ml tube. The total volume of sample is increased to 20 mls using deionized water.
6. Add 100 microliters of scandium if samples are to be analyzed by ICP.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 026

Residue, Filterable (Gravimetric, Dried at 180-C)

INSTRUMENTATION: Drying Oven

SCOPE AND APPLICATION -- This method is applicable to drinking, surface, and saline waters, domestic and industrial wastes. The practical range of the determination is 10 mg/L to 20,000 mg/L.

SUMMARY OF METHOD -- A well-mixed sample is filtered through a standard glass fiber filter. The filtrate is evaporated and dried to constant weight at 180-C. If Residue, Non-Filterable is being determined, the filtrate from that method may be used for Residue, Filterable.

DEFINITIONS -- Filterable residue is defined as those solids capable of passing through a glass fiber filter a
nd dried to constant weight at 180-C.

SAMPLE HANDLING AND PRESERVATION -- Preservation of the sample is not practical; analysis should begin as soon as possible. Refrigeration or icing to 4-C, to minimize micro-biological decomposition of solids, is recommended.

INTERFERENCES -- Highly mineralized waters containing significant concentrations of calcium, magnesium, chloride and/or sulfate may be hygroscopic and will require prolonged drying, desiccation and rapid weighing. Samples containing high concentrations of bicarbonate will require careful and possibly prolonged drying at 180-C to insure that all the bicarbonate is converted to carbonate. Too much residue in the evaporating dish will crust over and entrap water that will not be driven off during drying. Total residue should be limited to about 200 mg.

APPARATUS -- Glass fiber filter discs, 4.7 cm or 2.1 cm, without organic binder, Reeve Angel type 934-AH, Gelman type A/E, or equivalent. Filter holder, membrane filter funnel or Gooch crucible adapter. Suction flask, 500 mL. Gooch crucibles, 25 mL (if 2.1 cm filter is used). Evaporating dishes, porcelain, 100 mL volume. (Vycor or platinum dishes may be substituted). Steam bath. Drying oven, 180- C +/- 2-C. Desiccator. Analytical balance, capable of weighing to 0.1 mg.

PROCEDURE -- Preparation of glass fiber filter disc: Place the disc on the membrane filter apparatus or insert into bottom of a suitable Gooch crucible. While vacuum is app lied, wash the disc with three successive 20 mL volumes of distilled water. Remove all traces of water by continuing to apply vacuum after water has passed through. Discard washings. Preparation of evaporating dishes: If Volatile Residue is also to be measured heat the clean dish to 550 +/- 50-C for one hour in a muffle furnace. If only Filterable Residue is to be measured heat the clean dish to 180 +/- 2-C for one hour. Cool in desiccator and store until needed. Weigh immediately before use. Assemble the filtering apparatus and begin suction. Shake the sample vigorously and rapidly transfer 100 mL to the funnel by means of a 100 mL graduated cylinder. If total filterable residue is low, a larger volume may be filtered. Filter the sample through the glass fiber filter, rinse with three 10 mL portions of distilled water and continue to apply vacuum for about 3 minutes after filtration is complete to remove as much water as possible. Transfer 100 mL (or a larger volume) of the filtrate to a weighed evaporating dish and evaporate to dryness on a steam bath. Dry the evaporated sample for at least one hour at 180 plus or minus 2-C. Cool in a desiccator and weigh. Repeat the drying cycle until a constant weight is obtained or until weight loss is less than 0.5 mg.

CALCULATE FILTERABLE RESIDUE AS FOLLOWS:

Filterable residue, mg/ml = (A - B) * 1,000
                                                     C
where:

A = weight of dried residue + dish in mg
B = weight of dish in mg
C = volume of sample used in mL

Precision and Accuracy are not available at this time.

BIBLIOGRAPHY

Standard Methods for the Examination of Water and Wastewater, 14th Edition, p 92, Method 208B, (1975).

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 027

Residue, Non-Filterable (Gravimetric, Dried at 103 - 105-C)

INSTRUMENTATION: Drying Oven

SCOPE AND APPLICATION -- This method is applicable to drinking, surface, and saline water, domestic and industrial wastes. The practical range of the determination is 4 mg/L to 20,000 mg/L.

SUMMARY OF METHOD -- A well-mixed sample is filtered through a glass fiber filter, and the residue retained on the filter is dried to constant weight at 103 - 105-C. The filtrate from this method may be used for Residue, Filterable.

DEFINITIONS -- Residue, non-filterable, is defined as those solids which are retained by a glass fiber filter and dried to constant weight at 103 - 105-C.

SAMPLE HANDLING AND PRESERVATION -- Non-representative particulates such as leaves, sticks, fish, and lumps of fecal matter should be excluded from the sample if it is determined that their inclusion is not desired in the final result. Preservation of the sample is not practical; analysis should begin as soon as possible. Refrigeration or icing to 4-C, to minimize microbiological decomposition of solids, is recommended.

INTERFERENCES -- Filtration apparatus, filter material, pre-washing, post-washing, and drying temperature are specified because these variables have been shown to affect the results. Samples high in Filterable Residue (dissolved solids), such as saline waters, brines and some wastes, may be subject to a positive interference. Care must be taken in selecting the filtering apparatus so that washing of the filter and any dissolved solids in the filter (7.5) minimizes this potential interference.

APPARATUS -- Glass fiber filter discs, without organic binder, such as Millipore AP-40, Reeves Angel 934-AH, Gelman type A/E, or equivalent. NOTE: Because of the physical nature of glass fiber filters, the absolute pore size cannot be controlled or measured. Terms such as "pore size", collection efficiencies and effective retention are used to define this property in glass fiber filters. Values for these parameters vary for the filters listed above. Filter support: filtering apparatus with reservoir and a coarse (40-6- microns) fritted disc as a filter support.

NOTE: Many funnel designs are available in glass or porcelain. Some of the most common are Hirsch or Buchner funnels, membrane filter holders and Gooch crucibles. All are available with coarse fritted disc.

Suction flask. Drying oven, 103 - 105-C. Desiccator. Analytical balance, capable of weighing to 0.1 mg.

PROCEDURE -- Preparation of glass fiber filter disc: Place the glass fiber filter on the membrane filter apparatus or insert into bottom of a suitable Gooch crucible with wrinkled surface up. While vacuum is applied, wash the disc with three successive 20 mL volumes of distilled water. Remove all traces of water by continuing to apply vacuum after water has passed through. Remove filter from membrane filter apparatus or both crucible and filter if Gooch crucible is used, and dry in an oven at 103 - 105-C for one hour. Remove to desiccator and store until needed. Repeat the drying cycle until a constant weight is obtained (weight loss is less than 0.5 mg). Weigh immediately before use. After weighing, handle the filter or crucible/filter with forceps or tongs only. Selection of Sample Volume for a 4.7 cm diameter filter, filter 100 mL of sample. If weight of captured residue is less than 1.0 mg, the sample volume must be increased to provide at least 1.0 mg of residue. If other filter diameters are used, start with a sample volume equal to 7 mL/cm2 of filter area and collect at least a weight of residue proportional to the 1.0 mg stated above.

NOTE: If during filtration of this initial volume the filtration rate drops rapidly, or if filtration time exceeds 5 to 10 minutes, the following scheme is recommended: Use an unweighed glass fiver filter of choice affixed in the filter assembly. Add a known volume of sample to the filter funnel and record the time elapsed after selected volumes have passed through the filter. Twenty- five mL increments for timing are suggested. Continue to record the time and volume increments until filtration rate drops rapidly. Add additional sample if the filter funnel volume is inadequate to reach a reduced rate. Plot the observed time versus volume filtered. Select the proper filtration volume as that just short of the time a significant change in filtration rate occurred.

Assemble the filtering apparatus and begin suction. Wet the filter with a small volume of distilled water to seat it against the fritted support. Shake the sample vigorously and quantitatively transfer the predetermined sample volume selected in 7.2 to the filter using a graduated cylinder. Remove all traces of water by continuing to apply vacuum after sample has passed through. With suction on, wash the graduated cylinder, filter, non-filterable residue and filter funnel wall with three portions of distilled water allowing complete drainage between washing. Remove all traces of water by continuing to apply vacuum after water has passed through. NOTE: Total volume of wash water used should equal approximately 2 mL per cm2 for a 4.7 cm filter the total volume is 30 mL. Carefully remove the filter from the filter support. Alternatively, remove crucible and filter from crucible adapter. Dry at least one hour at 103 - 105 C. Cool in a desiccator and weigh. Repeat the drying cycle until a constant weight is obtained (weight loss is less than 0.5 mg).

CALCULATE NON-FILTERABLE RESIDUE AS FOLLOWS:

Non-filterable residue, mg/ml = (A - B) x 1,000
                                                            C
where:

A = weight of filter (or filter and crucible) + residue in mg
B = weight of filter (or filter and crucible) in mg
C = mL of sample filtered

Precision and Accuracy are not available at this time. Accuracy data on actual samples cannot be obtained.

BIBLIOGRAPHY

NCASI Technical Bulletin No. 291, March 1977. National Council of the Paper Industry for Air and Stream Improvement, Inc., 260 Madison Ave., NY.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 028

 

This method code is used when liquid samples, such as waters, are analyzed as they were received at our laboratory. Samples did not have any further preparation prior to being analyzed for specific analytes.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 029

Determination of Acid Volatile Sulfide in Sediments

Determination of AVS (acid volatile sulfide) in a sediment is conducted by treatment of the sample for one hour with dilute HC1 in an oxygen- free atmosphere. The resultant hydrogen sulfide which forms is purged by nitrogen into a sodium hydroxide trapping solution. Free sulfide ion is rapidly formed in the trap which is then measured by a sulfide- specific electrode.

Back to the Top Back to the Top Arrow


Lab Name: Environmental Trace Substance Laboratory (ETSL) Labratory                                         Method Code: 030

Total Cyanide Detection from Water Samples

This method comprises of two parts: distillation and colorimetry. The QC standard, with certified value of 59.2 mg/L total cyanide, was purchased from Environmental Resource Associates, 5540 Marshall St. Arvada, Colorado 80002. Cat. #502, Lot # 99110.

A. Distillation:

1. Add 250 ml of water sample to the 500-mL round bottom flask.
2. Add 10 ml of 1N NaOH solution to the gas scrubber and dilute with DI water to about 150 ml.
3. Connect the cyanide distillation apparatus. Turn on the cold water for the condenser. Adjust gas flow rate.
4. Add 2 g sulfamic acid through the air inlet tube and wash down with DI water.
5. Add 50 ml 1:1 H2SO4 through the air inlet tube. Let air mix flask contents for 3 min.
6. Add 20 ml MgCl2 reagent and wash down with DI water.
7. Heat the sample to boil and reflux for one hour.
8. Discontinue heating but continue air flow for 15 min. Cool and quantitatively transfer absorption solution to a 250-ml volumetric flask. Dilute to volume with DI water.
9. Determine cyanide concentration in absorption solution by colorimetric method.

B. Colorimetry:

1. Standard curve: Pipet a series of standards containing 0, 1, 2, 4, 6, 8, 10 mg CN- into 50-ml volumetric flask
s. Dilute to 40 ml with NaOH dilution solution.
2. Sample: Pipet a portion of absorption solution from step A into a 50-ml volumetric flask and dilute to 40 ml with NaOH dilution solution.
3. Add 1 ml acetate buffer and 2 ml chloramines-T solution to each flask, mix well and let stand for 2 min.
4. Add 5 ml pyridine-barbituric acid reagent to each flask. Dilute to volume with DI water. Mix well and let stand for 8 min.
5. Measure absorbance against DI water at 578 nm.
6. Make standard curve and measure the cyanide concentration of the samples.

Back to the Top Back to the Top Arrow