USGS-NWQL: B-9001-95 (ICP-AES): Trace Metals in Aquatic Biological Material by ICP-AES

Summary
Analytes
Revision
Data and Sites

Official Method Name

Preparation Procedure for Aquatic Biological Material Determined for Trace Metals

Current Revision

1996

Media

ANIMAL TISSUE

Instrumentation

Inductively Coupled Plasma - Atomic Emission Spectroscopy

Method Subcategory

Sampling/Preparation

Method Source

USGS-NWQL

Citation

Hoffman, G.L., 1996, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory -- Preparation procedure for aquatic biological material determined for trace metals: U.S. Geological Survey Open-File Report 96-362.

Brief Method Summary

Up to 20 g of wet tissue is placed into a tared 200-mL Pyrex beaker and weighed. The sample is placed in a constant-temperature oven and dried at 65^oC over several days until constant weight is obtained. The sample is digested by first heating it with nitric acid and then by the careful addition of 30% hydrogen peroxide. Insoluble material (silica or sediment) is removed by filtration. Trace metals determined in the solutions are reported in micrograms per gram (ug/g) of dry-tissue weight.

Scope and Application

This method provides sample-preparation procedures for the nitric acid digestion of biological tissue for the subsequent determination of trace metals. The method is applicable to aquatic biological tissue and aquatic plant material only and is not applicable to bivalve shells, bones, and sediment material contained in bivalves.

Applicable Concentration Range

> 0.01 ug/g

Interferences

Chloride concentrations greater than 0.01% can cause analytical problems for ICP-MS used to determine trace metals by this digestion method. Therefore, hydrochloric acid was not used during the digestion procedure. The digested samples also were evaporated to near dryness and reconstituted with 5% nitric acid to remove all chloride present in the digested samples.
A clean working environment is required (Katz, 1984). The use of a class-100 clean bench during all manipulations, including filtration, drying of cleaned glassware, and acid rinsing of filters, is mandatory.

Quality Control Requirements

QC for digestion procedure: Digest a synthetic biological material that is based on National Institute of Standards and Technology (NIST) Oyster tissue, SRM 1655a; NIST Bovine liver, SRM 1577a; and/or NIST Peach leaves, SRM 1547. Also digest a process blank consisting of all reagents used in the tissue-digestion procedure. QC for ICP-AES analysis: Analyze a quality-control sample immediately following calibration and after every tenth sample. Minimum quality-control requirements per set must include analysis of a laboratory reagent blank and quality-control samples, such as SRWS, and may include check standards, sample duplicates, and sample spikes. The sample set must also include a synthetic biological material that is based on an NIST SRM. The sample set must also include a process blank to verify the accuracy of the procedure. Correlation coefficients for calibration curves must be at least 0.999. QC samples must fall within 1.5 standard deviations of the mean value. If all of the data-acceptance criteria in the SOPs are met, then the analytical data are acceptable.

Sample Handling

Biological material must be frozen when received at the laboratory, packed with dry ice in an insulated cooler. Inspect all resealable bags to ensure the integrity of the bag and the condition of the samples. Record the condition of all compromised samples (torn bags or samples not frozen) in the sample preparation notebook. Inform the investigator who shipped the samples of their compromised condition. Double bag tissue samples in resealable polyethylene freezer bags and store in a freezer maintained at less than or equal to -10^oC until sample preparation.

Maximum Holding Time

It is possible to maintain the inorganic chemical integrity of frozen biological samples for years provided the samples are not thawed and refrozen.

Relative Cost

$51 to $200

Sample Preparation Methods

This method has 16 analytes associated with it.

Analyte	Detection Level	Bias	Precision	Spiking Level
Aluminum(7429-90-5) Al Aluminium Aluminum Aluminum (fume or dust) Aluminum powder	N/A	94% Rec (SL)	8.50 RSD	10.00 ug/g
Barium(7440-39-3) Ba Barium	N/A	96% Rec (SL)	2.08 RSD	1.00 ug/g
Beryllium(7440-41-7) Be Beryllium Glucinium	N/A	101% Rec (SL)	0.99 RSD	0.02 ug/g
Boron(7440-42-8) B Boron Boron (Boron and Borates only)	N/A	96% Rec (SL)	1.04 RSD	0.50 ug/g
Cadmium(7440-43-9) Cadmium Cd	N/A	93% Rec (SL)	2.15 RSD	0.05 ug/g
Chromium(7440-47-3) Chromium Cr	N/A	93% Rec (SL)	4.30 RSD	0.50 ug/g
Copper(7440-50-8) Copper Copper (metallic) Cu	N/A	98% Rec (SL)	2.04 RSD	1.00 ug/g
Iron(7439-89-6) Fe Iron	0.600 ug/g	95% Rec (SL)	10.53 RSD	10.00 ug/g
Lead(7439-92-1) Lead Lead and compounds (inorganic) Lead and lead compounds Pb	N/A	94% Rec (SL)	12.77 RSD	0.10 ug/g
Manganese(7439-96-5) Manganese Mn	N/A	97% Rec (SL)	3.09 RSD	10.00 ug/g
Molybdenum(7439-98-7) Amperit 105.054 Amperit 106.2 EINECS 231-107-2 HSDB 5032 MChVL Metco 63 Mo Molybdenum Molybdenum, metallic TsM1	N/A	93% Rec (SL)	3.23 RSD	0.10 ug/g
Nickel(7440-02-0) Ni Nickel Nickel, soluble salts Raney Nickel (R)	N/A	92% Rec (SL)	2.17 RSD	0.10 ug/g
Silver(7440-22-4) Ag Silver	N/A	96% Rec (SL)	2.08 RSD	0.05 ug/g
Strontium(7440-24-6) Sr Strontium	N/A	96% Rec (SL)	4.17 RSD	0.50 ug/g
Vanadium(7440-62-2) V Vanadium Vanadium (fume or dust)	N/A	96% Rec (SL)	2.08 RSD	0.10 ug/g
Zinc(7440-66-6) Zinc Zinc (fume or dust) Zinc and Compounds Zn	N/A	93% Rec (SL)	5.38 RSD	2.00 ug/g

Precision Descriptor Notes:	The following samples were analyzed to evaluate the contamination, method detection limits, precision, accuracy, and recovery of the tissue-preparation and analytical procedures for the trace metals determined: (1) three NIST standard reference biological materials (Oyster tissue SRM 1566a, Bovine liver SRM 1577b, and Peach leaves SRM 1547); (2) two NWQL prepared biological tissue homogenates (Corbicula tissue and Salmo livers); and (3) process blanks consisting of all reagents used in the tissue-digestion procedure. All metals determined in the Corbicula-tissue and Salmo-liver homogenate samples were spiked to evaluate possible interferences. Short-term (single-set) variation was compared to long-term (multiple-set) variation for precision, accuracy, and contamination. The MDL, precision, and accuracy data presented here in the NEMI database are for the Corbicula-tissue homogenate. Refer to the method report for data for the rest of the sample results.
Detection Level Note:	Method detection limits (MDLs) were determined for this method using the U.S. Environmental Protection Agency (USEPA) MDL method (1992).

Precision Descriptor Notes:

The following samples were analyzed to evaluate the contamination, method detection limits, precision, accuracy, and recovery of the tissue-preparation and analytical procedures for the trace metals determined: (1) three NIST standard reference biological materials (Oyster tissue SRM 1566a, Bovine liver SRM 1577b, and Peach leaves SRM 1547); (2) two NWQL prepared biological tissue homogenates (Corbicula tissue and Salmo livers); and (3) process blanks consisting of all reagents used in the tissue-digestion procedure. All metals determined in the Corbicula-tissue and Salmo-liver homogenate samples were spiked to evaluate possible interferences. Short-term (single-set) variation was compared to long-term (multiple-set) variation for precision, accuracy, and contamination. The MDL, precision, and accuracy data presented here in the NEMI database are for the Corbicula-tissue homogenate. Refer to the method report for data for the rest of the sample results.

Detection Level Note:

Method detection limits (MDLs) were determined for this method using the U.S. Environmental Protection Agency (USEPA) MDL method (1992).

Revision	PDF/Link
1996

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USGS-NWQL: B-9001-95 (ICP-AES): Trace Metals in Aquatic Biological Material by ICP-AES

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