USGS-NWQL: I-4472-97: Metals in Water by Inductively Coupled Plasma/Mass Spectrometer, Whole-Water Recoverable

Summary
Analytes
Revision
Data and Sites

Official Method Name

Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory - Determination of Elements in Whole-Water Digests Using Inductively Coupled Plasma-Optical Emission Spectrometry a

Current Revision

1998

Media

WATER

Instrumentation

Inductively Coupled Plasma - Mass Spectrometry

Method Subcategory

Inorganic

Method Source

USGS-NWQL

Citation

Garbarino, J.R., and Struzeski, T.M., 1998, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory -- Determination of elements in whole-water digests using inductively coupled plasma-optical emission spectrometry and inductively coupled plasma-mass spectrometry: U.S. Geological Survey Open-File Report 98-165.

Brief Method Summary

Whole-water recoverable elements are determined simultaneously on a single sample by using inductively coupled plasma-mass spectrometry. An aerosol of the sample solution is produced by using a high dissolved-solids tolerant nebulizer. The aerosol is introduced into the argon plasma where it undergoes desolvation, atomization, and ionization. Ions are sampled through multiple orifices into the quadrupole mass spectrometer where they are separated on the basis of their mass-to-charge ratios. An electron multiplier detects the ions by generating an electrical current that is directly proportional to the concentration of the element present in the sample.
Arsenic, boron, and vanadium was added to the suite of analytes for this method in 1999. The methodology remains the same; however, this addition is documented in Grabarino, J.R., 2000, Methods of Analysis by the U.S.Geological Survey National Water Quality Laboratory - Determination of Whole-Water Recoverable Arsenic, Boron, and Vanadium Using Inductively Coupled Plasma-Mass Spectrometry: U.S.Geological Survey Open-File Report 99-464. NOTE: This report incorrectly lists the method identification number as I-4471-97.

Scope and Application

This method is used to determine recoverable aluminum, antimony, barium, beryllium, cadmium, chromium, cobalt, copper, lead, lithium, manganese, molybdenum, nickel, selenium, silver, strontium, thallium, uranium, and zinc in natural whole-water samples digested by using the in-bottle procedure that is described by Hoffman and others (1996). The method calibration ranges were optimized for elemental concentrations normally found in natural water, however, the dynamic range for ICP-MS is linear to a maximum of about 1 mg/L for elements that are monoisotopic, and somewhat greater than 1 mg/L for elements that have multiple isotopes.

Applicable Concentration Range

25-200

Interferences

Several types of physical and spectral interference are recognized and documented for ICP-MS techniques. Physical interferences are associated primarily with sample introduction and are minimized by using the internal standardization technique. Isotopes measured in this procedure have been selected specifically to minimize spectral interferences from isobaric, doubly charged, and molecular ions. Multiple isotopes can be measured for selected elements that have potential isobaric or molecular ion interferences. Data from multiple isotopes can indicate the presence and magnitude of interferences. The analyst must be conscious of these interferences because they might occur with certain types of sample matrices.
The effects of sample transport, instrumental drift, and matrix-induced fluctuations in plasma characteristics are reduced by using the ratio of elemental ion intensity to the internal standard element ion intensity for calibration. Memory effects related to sample transport are negligible for most elements normally present in whole-water digests.
Whenever possible, the isotope used for quantitation has no spectral interferences or has a small number of potential spectral interferences that is unlikely to occur in whole-water digests or can easily be corrected. Spectral interferences can originate from isobaric ions, molecular ions, or doubly charged ions. The analyst must be aware of these potential spectral interferences when reviewing analytical results. Spectral overlap contributions caused by insufficient abundance sensitivity are negligible and can be minimized by measuring each isotope at three points that transect the peak maximum, which is centered at the nominal mass.

Quality Control Requirements

Quality-control samples area analyzed at a minimum of one in every ten samples. These QC samples include at least one of each of the following: blanks, quality control samples, third party check solutions, replicates, and spikes. Correlation coefficients for calibration curves must be at least 0.99. 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

Description: 250 mL Polyethylene bottle, acid-rinsed. Treatment and Preservation: Use unfiltered sample to rinse bottles, then acidify collected sample with nitric acid (HNO₃) to pH < 2.

Maximum Holding Time

180 days from sampling

Relative Cost

Less than $50

Sample Preparation Methods

USGS-WRIR 96-225

This method has 22 analytes associated with it.

Analyte	Detection Level	Bias	Precision
Aluminum(7429-90-5) Al Aluminium Aluminum Aluminum (fume or dust) Aluminum powder	1.000 ug/L	N/A	N/A
Antimony(7440-36-0) Antimony Sb Stibium	0.700 ug/L	N/A	N/A
Arsenic(7440-38-2) Arsenic As	0.070 ug/L	N/A	N/A
Barium(7440-39-3) Ba Barium	0.080 ug/L	N/A	N/A
Beryllium(7440-41-7) Be Beryllium Glucinium	0.070 ug/L	N/A	N/A
Boron(7440-42-8) B Boron Boron (Boron and Borates only)	0.500 ug/L	N/A	N/A
Cadmium(7440-43-9) Cadmium Cd	0.050 ug/L	N/A	N/A
Chromium(7440-47-3) Chromium Cr	2.000 ug/L	N/A	N/A
Cobalt(7440-48-4) Co Cobalt	0.040 ug/L	N/A	N/A
Copper(7440-50-8) Copper Copper (metallic) Cu	0.300 ug/L	N/A	N/A
Lead(7439-92-1) Lead Lead and compounds (inorganic) Lead and lead compounds Pb	0.050 ug/L	N/A	N/A
Lithium(7439-93-2) Li Lithium	0.040 ug/L	N/A	N/A
Manganese(7439-96-5) Manganese Mn	0.060 ug/L	N/A	N/A
Molybdenum(7439-98-7) Amperit 105.054 Amperit 106.2 EINECS 231-107-2 HSDB 5032 MChVL Metco 63 Mo Molybdenum Molybdenum, metallic TsM1	0.400 ug/L	N/A	N/A
Nickel(7440-02-0) Ni Nickel Nickel, soluble salts Raney Nickel (R)	0.300 ug/L	N/A	N/A
Selenium(7782-49-2) Se Selenium Selenium and Compounds	2.000 ug/L	N/A	N/A
Silver(7440-22-4) Ag Silver	0.700 ug/L	N/A	N/A
Strontium(7440-24-6) Sr Strontium	0.040 ug/L	N/A	N/A
Thallium(7440-28-0) Thallium Tl	0.300 ug/L	N/A	N/A
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	0.200 ug/L	N/A	N/A
Vanadium(7440-62-2) V Vanadium Vanadium (fume or dust)	0.080 ug/L	N/A	N/A
Zinc(7440-66-6) Zinc Zinc (fume or dust) Zinc and Compounds Zn	0.500 ug/L	N/A	N/A

Precision Descriptor Notes:	Spike recovery percentages were determined for the new elements in matrices representative of reagent-water, surface-water, ground-water, and whole-water digests. Seven replicate recoveries at 5 to 10 times the MDL (the low-level spike) and 75 mg/L (the high-level spike) were determined in each matrix over a period of about 1 week. Average recoveries in the reagent-water matrix ranged from 77 to 105. Recovery variability for the low-level spike ranged from 4 to 9 percent, depending on the element. Ambient concentrations of vanadium in the surface water, however, hindered the recovery of the low-level spike. Recovery of low-level arsenic and boron ranged from 88 to 112 percent. The variability in the recovery of 1 ug/L boron in the presence of 40 ug/L boron was 52 percent; the variability for arsenic was less than 6 percent at about the same spike concentration.
Detection Level Note:	Method detection limits (MDLs) were determined for this method using the procedures of the U.S. Environmental Protection Agency (1997).

Precision Descriptor Notes:

Spike recovery percentages were determined for the new elements in matrices representative of reagent-water, surface-water, ground-water, and whole-water digests. Seven replicate recoveries at 5 to 10 times the MDL (the low-level spike) and 75 mg/L (the high-level spike) were determined in each matrix over a period of about 1 week. Average recoveries in the reagent-water matrix ranged from 77 to 105. Recovery variability for the low-level spike ranged from 4 to 9 percent, depending on the element. Ambient concentrations of vanadium in the surface water, however, hindered the recovery of the low-level spike. Recovery of low-level arsenic and boron ranged from 88 to 112 percent. The variability in the recovery of 1 ug/L boron in the presence of 40 ug/L boron was 52 percent; the variability for arsenic was less than 6 percent at about the same spike concentration.

Detection Level Note:

Method detection limits (MDLs) were determined for this method using the procedures of the U.S. Environmental Protection Agency (1997).

Revision	PDF/Link
1998

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USGS-NWQL: I-4472-97: Metals in Water by Inductively Coupled Plasma/Mass Spectrometer, Whole-Water Recoverable

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