USGS-NWQL: I-3487-98: Comparison of In-Bottle and Other Whole-Water Digestion Procedures

Summary
Analytes
Revision
Data and Sites

Official Method Name

Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory - Comparison of a Nitric Acid In-Bottle Digestion Procedure to Other Whole-Water Digestion Procedures

Current Revision

1999

Media

WATER

Instrumentation

Inductively Coupled Plasma - Mass Spectrometry

Method Subcategory

Inorganic

Method Source

USGS-NWQL

Citation

Garbarino, J.R., and Hoffman, G.L., 1999, Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory -- Comparison of nitric acid in-bottle digestion procedure to other whole-water digestion procedures: U.S. Geological Survey Open-File Report 99-094.

Brief Method Summary

Hoffman and others (1996) have previously described an HCl in-bottle digestion procedure. The HNO3 in-bottle procedure requires minor modifications to the HCl in-bottle procedure. After the preparatory procedure, the digestate can be analyzed by using DCP-AES, ICP-AES, ICP-MS, HG-AAS, GF-AAS and F-AAS. Details of these analytical methods can be obtained in Fishman (1993), Fishman and Friedman (1989), Garbarino and Struzeski (1998), and Jones and Garbarino (1999).

Scope and Application

This method was developed to digest whole-water samples by using an HNO3 in-bottle procedure to determine the elements listed in method I-1472-87.

Applicable Concentration Range

Interferences

There are no known interferences associated with procedures described in this report.

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: Filter through 0.45-um filter, use filtered sample to rinse containers and acidify sample with nitric acid (HNO₃) to pH < 2.

Maximum Holding Time

180 days from sampling

Relative Cost

Sample Preparation Methods

This method has 1 analyte associated with it.

Analyte	Detection Level	Bias	Precision	Pct False Positive	Pct False Negative	Spiking Level
pH(E-10139) Acidity Hydrogen ion pH	N/A	N/A	N/A

Precision Descriptor Notes:	Advantages of using the HNO₃ in-bottle digestion procedure: the digestate is compatible with all current (1999) USGS analytical methods used to determine aluminum, antimony, arsenic, barium, beryllium, boron, cadmium, calcium, chromium, cobalt, copper, iron, lead, lithium, magnesium, manganese, molybdenum, nickel, potassium, selenium, silica, silver, sodium, strontium, thallium, uranium, vanadium, and zinc; the variability of 0.1 to 8 percent is comparable to the HCl in-bottle digestion procedure; the procedure uses less chemical reagents and, therefore, produces less chemical waste for some analytical methods and interferences from chloride are reduced. Disadvantage of using the HNO₃ in-bottle digestion procedure: results from the synthetic whole-water samples indicate that the HNO₃ in-bottle procedure might give negatively biased recoverable concentrations relative to the HCl in-bottle procedure. Recoverable concentrations are dependent on the composition of the particulate matter in the whole-water sample regardless of the digestion procedure used. Both the HCl and HNO₃ in-bottle digestion procedures give excellent reproducibility for all elements determined. Therefore, the simplicity of the digestion procedure should be the primary reason for the method selected. The HNO₃ in-bottle digestion is the preferred method for routine use at the National Water Quality Laboratory. Nevertheless, the original HCl in-bottle digestion procedure can be used if customers require this acid-digestion procedure.
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:

Advantages of using the HNO₃ in-bottle digestion procedure: the digestate is compatible with all current (1999) USGS analytical methods used to determine aluminum, antimony, arsenic, barium, beryllium, boron, cadmium, calcium, chromium, cobalt, copper, iron, lead, lithium, magnesium, manganese, molybdenum, nickel, potassium, selenium, silica, silver, sodium, strontium, thallium, uranium, vanadium, and zinc; the variability of 0.1 to 8 percent is comparable to the HCl in-bottle digestion procedure; the procedure uses less chemical reagents and, therefore, produces less chemical waste for some analytical methods and interferences from chloride are reduced. Disadvantage of using the HNO₃ in-bottle digestion procedure: results from the synthetic whole-water samples indicate that the HNO₃ in-bottle procedure might give negatively biased recoverable concentrations relative to the HCl in-bottle procedure. Recoverable concentrations are dependent on the composition of the particulate matter in the whole-water sample regardless of the digestion procedure used. Both the HCl and HNO₃ in-bottle digestion procedures give excellent reproducibility for all elements determined. Therefore, the simplicity of the digestion procedure should be the primary reason for the method selected. The HNO₃ in-bottle digestion is the preferred method for routine use at the National Water Quality Laboratory. Nevertheless, the original HCl in-bottle digestion procedure can be used if customers require this acid-digestion procedure.

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
1999

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USGS-NWQL: I-3487-98: Comparison of In-Bottle and Other Whole-Water Digestion Procedures

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