EPA-NERL: 200.8: Metals in Waters by ICP/MS

Summary
Analytes
Revision
Data and Sites

Official Method Name

Determination of Trace Elements in Waters by Inductively Coupled Plasma - Mass Spectrometry

Current Revision

Revision 5.4, 1994

Media

WATER

Instrumentation

Inductively Coupled Plasma - Mass Spectrometry

Method Subcategory

Inorganic

Method Source

EPA-NERL

Citation

Methods for the Determination of Metals in Environmental Samples, Supplement 1 (EPA/600/R-94/111)

Brief Method Summary

Except for the determination of dissolved analytes aqueous samples are acid preserved prior to sample processing. For the analysis of dissolved analytes, an acidified portion the filtrate is analyzed directly. For the determination of total-recoverable analytes in aqueous samples containing particulate material as well as solid type samples, samples are subjected to acid pretreatment with nitric and hydrochloric acids and gentle refluxing prior to analysis. The method involves multi-element determination by inductively coupled plasma-mass spectrometry. Sample solutions are pneumatically nebulized into a radio-frequency plasma where ionization occurs. The ions are extracted from the plasma through a differentially pumped vacuum interface and separated on the basis of their mass-to-charge ratio by a quadruple mass spectrometer. Separated ions are detected by an electron multiplier or Faraday detector and the ion information processed by a data handling system. Isobaric and polyatomic interferences relating to the technique must be recognized and corrected. Instrument drift and matrix effects must be corrected with the use of internal standards.

Scope and Application

This method determines 21 elements as dissolved elements in ground waters, surface waters, and drinking water, and total recoverable elements in these waters as well as wastewaters, sludges, and soils samples. Total-recoverable determination data should be reported as "total" (dissolved + suspended fractions) metal data. Organometalic compounds (such as arsenic compounds) are only determined as "total metals" and not as the individual organometalic compounds.

Applicable Concentration Range

The analytical range depends on the type of detector utilized (electron multiplier or Faraday cup) and extends from the laboratory determined MDL to the upper limit of the linear dynamic range.

Interferences

(1) Isobaric elemental interferences caused by isotopes of different elements which form singly or doubly charged ions of the same nominal mass-to-charge ratio and cannot be resolved by the mass spectrometer in use.
(2) Signals from relatively abundant isotopes can coalesce at the wings of relatively less abundant isotopes leading to loss of resolution and poorer quantitation.
(3) Isobaric polyatomic ion interferences are caused by ions consisting of more than one atom with the same nominal charge-to-mass ratio of the isotope of interest.
(4) Physical interferences that hinder transport of the sample into the plasma (e.g., viscosity effects, high levels of solids).
(5) Memory interferences (carry-over) of isotopes from previous sample runs.

Quality Control Requirements

Calibration Blanks (CBs), Laboratory Reagent Blanks (LRBs), Laboratory Duplicates (LDs), Laboratory Fortified Sample Matrix (LFM), Quality Control Samples (QCSs)

Sample Handling

For dissolved elements, filter aqueous sample through a 0.45-um pore membrane filter. Adjust the pH of the filtrate to < 2 with HNO₃. For total recoverable elements, adjust the pH of the aqueous sample to < 2 with HNO₃.

Maximum Holding Time

6 months (All metals except Hg - 28 days)

Relative Cost

$201 to $400

Sample Preparation Methods

This method has 22 analytes associated with it.

Analyte	Detection Level	Bias	Precision	Spiking Level
Aluminum(7429-90-5) Al Aluminium Aluminum Aluminum (fume or dust) Aluminum powder	1.000 ug/L	125% Rec (ML)	17.40 % RSD (ML)	8.00 ug/L
Antimony(7440-36-0) Antimony Sb Stibium	0.400 ug/L	98% Rec (ML)	9.80 % RSD (ML)	2.80 ug/L
Arsenic(7440-38-2) Arsenic As	1.400 ug/L	108% Rec (ML)	35.00 % RSD (ML)	8.00 ug/L
Barium(7440-39-3) Ba Barium	0.800 ug/L	95% Rec (ML)	6.30 % RSD (ML)	8.01 ug/L
Beryllium(7440-41-7) Be Beryllium Glucinium	0.300 ug/L	118% Rec (ML)	7.90 % RSD (ML)	2.80 ug/L
Cadmium(7440-43-9) Cadmium Cd	0.500 ug/L	100% Rec (ML)	5.00 % RSD (ML)	4.00 ug/L
Chromium(7440-47-3) Chromium Cr	0.900 ug/L	103% Rec (ML)	18.60 % RSD (ML)	8.00 ug/L
Cobalt(7440-48-4) Co Cobalt	0.090 ug/L	110% Rec (ML)	5.70 % RSD (ML)	0.80 ug/L
Copper(7440-50-8) Copper Copper (metallic) Cu	0.500 ug/L	97% Rec (ML)	15.20 % RSD (ML)	4.00 ug/L
Lead(7439-92-1) Lead Lead and compounds (inorganic) Lead and lead compounds Pb	0.600 ug/L	100% Rec (ML)	40.50 % RSD (ML)	4.00 ug/L
Manganese(7439-96-5) Manganese Mn	0.100 ug/L	108% Rec (ML)	10.50 % RSD (ML)	0.80 ug/L
Mercury(7439-97-6) Hg Hydrargyrum Liquid silver Mercury Mercury (inorganic) Quicksilver	0.200 ug/L	86% Rec (SL)	13.00 % RSD (SL)	1.00 ug/L
Molybdenum(7439-98-7) Amperit 105.054 Amperit 106.2 EINECS 231-107-2 HSDB 5032 MChVL Metco 63 Mo Molybdenum Molybdenum, metallic TsM1	0.300 ug/L	94% Rec (ML)	6.10 % RSD (ML)	2.80 ug/L
Nickel(7440-02-0) Ni Nickel Nickel, soluble salts Raney Nickel (R)	0.500 ug/L	101% Rec (ML)	12.50 % RSD (ML)	4.00 ug/L
Selenium(7782-49-2) Se Selenium Selenium and Compounds	7.900 ug/L	105% Rec (ML)	4.70 % RSD (ML)	32.00 ug/L
Silver(7440-22-4) Ag Silver	0.100 ug/L	116% Rec (ML)	15.10 % RSD (ML)	0.80 ug/L
Sodium arsenite(7784-46-5) EPA Pesticide Chemical Code 013603 Sodium arsenite Sodium metaarsenite	N/A	N/A	N/A
Thallium(7440-28-0) Thallium Tl	0.300 ug/L	103% Rec (ML)	7.60 % RSD (ML)	2.80 ug/L
Thorium-232(7440-29-1) Th Thorium Thorium-232	0.100 ug/L	116% Rec (ML)	9.70 % RSD (ML)	0.80 ug/L
Uranium-238(7440-61-1) 238U 238U Element U U-238 Uranium Uranium (PM10) STP Uranium (TSP) Uranium 238 Uranium PM2.5 LC Uranium PM2.5 STP Uranium, natural Uranium-238	0.100 ug/L	108% Rec (ML)	10.00 % RSD (ML)	0.80 ug/L
Vanadium(7440-62-2) V Vanadium Vanadium (fume or dust)	2.500 ug/L	97% Rec (ML)	6.80 % RSD (ML)	32.00 ug/L
Zinc(7440-66-6) Zinc Zinc (fume or dust) Zinc and Compounds Zn	1.800 ug/L	104% Rec (ML)	22.25 % RSD (ML)	8.00 ug/L

Precision Descriptor Notes:	Data (excluding that for mercury) was from joint EPA-AOAC 13-laboratory round robin validation. The precision and accuracy values presented are based on analyses of spiked reagent water samples. However, the method contains multilaboratory data and regression equations for metals analyses in drinking water, and ground water, and reagent water, as well supplemental single-laboratory data in a variety of matrices and media. NOTE: Mercury data was based on analyses of 3 drinking water samples fortified with mercury. One sample had background concentration above the MDL (0.23).
Detection Level Note:	(1) Instrument detection limits (3-sigma) estimated from seven-replicate integrations of the blank (1% v/v nitric acid) following calibration of the instrument with three replicate integrations of a multi-element standard. (2) IDLs were estimated from single-laboratory, reagent water data.

Precision Descriptor Notes:

Data (excluding that for mercury) was from joint EPA-AOAC 13-laboratory round robin validation. The precision and accuracy values presented are based on analyses of spiked reagent water samples. However, the method contains multilaboratory data and regression equations for metals analyses in drinking water, and ground water, and reagent water, as well supplemental single-laboratory data in a variety of matrices and media. NOTE: Mercury data was based on analyses of 3 drinking water samples fortified with mercury. One sample had background concentration above the MDL (0.23).

Detection Level Note:

(1) Instrument detection limits (3-sigma) estimated from seven-replicate integrations of the blank (1% v/v nitric acid) following calibration of the instrument with three replicate integrations of a multi-element standard. (2) IDLs were estimated from single-laboratory, reagent water data.

Revision	PDF/Link
Revision 5.4, 1994

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EPA-NERL: 200.8: Metals in Waters by ICP/MS

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