ASTM D1971

The determination of metals in water often requires the measurement of total (suspended and dissolved) metals as well as soluble (dissolved) metals. In such cases, consistent and dependable digestion procedures must be used so that data derived for the total metals content is reliable.

The practices given are applicable to a wide variety of sample types for the purpose of preparing a sample for metals analyses by atomic absorption spectrophotometry or plasma emission spectroscopy (see Test Methods D 1976, D 3919, D 4691, and D 4190) or plasma-mass spectrometry (See Test Method D 5673) and have been shown to give good recovery in the following matrices: industrial effluents; waste water treatment plant influents, sludges, dewatered sludges, and effluents; river and lake waters; and plant and animal tissues. Elements which have shown good recovery include: copper, nickel, lead, zinc, cadmium, iron, manganese, magnesium, and calcium.

4.2.1 Good recovery for the indicated sample types and metals may not be achieved at all times due to each sample’unique characteristics. Users must always validate the practice for their particular samples.

The analytical results achieved after applying these practices cannot necessarily be deemed as a measure of bioavailable or environmentally available elements.

These three practices may not give the same recovery when applied to the same sample, nor will they necessarily give the same results as achieved using other digestion techniques. An alternate digestion technique is Practice D 4309.

1. Scope

1.1 Most atomic absorption and plasma emission spectroscopy, and plasma-mass spectrometric test methods require that the metals of interest be dissolved in a liquid phase before being introduced into the spectrophotometer. These practices describe digestion or dissolution procedures whereby analyte metals associated with the solid fraction of a sample can be brought into solution for subsequent analysis. The following practices are included:

1.2 These practices have been demonstrated to be applicable to a wide variety of sample types and sample matrices, and in many cases, will give complete dissolution of the analyte metals of interest. They are by no means the only digestion procedures available.

1.3 The user of these practices should be cautioned that these practices may not completely dissolve all portions of a sample's solid phase and may not give complete recovery of the desired analyte metals. In these cases, other digestion techniques are available that will effect complete dissolution of a sample. It is the user's responsibility to ensure the validity of these practices for use on their particular sample matrix, for their metals of interest.

1.4 This practice assumes that the criteria established in Guide D 3856 can be met.

1.5 These digestion procedures have been selected for their wide application, low cost, and ease of use.

1.6 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 6.

2. Referenced Documents

D1068 Test Methods for Iron in Water
D1129 Terminology Relating to Water
D1192 Guide for Equipment for Sampling Water and Steam in Closed Conduits
D1193 Specification for Reagent Water
D1687 Test Methods for Chromium in Water
D1688 Test Methods for Copper in Water
D1691 Test Methods for Zinc in Water
D1886 Test Methods for Nickel in Water
D1976 Test Method for Elements in Water by Inductively-Coupled Argon Plasma Atomic Emission Spectroscopy
D3370 Practices for Sampling Water from Closed Conduits
D3372 Test Method for Molybdenum in Water
D3557 Test Methods for Cadmium in Water
D3558 Test Methods for Cobalt in Water
D3559 Test Methods for Lead in Water
D3645 Test Methods for Beryllium in Water
D3856 Guide for Good Laboratory Practices in Laboratories Engaged in Sampling and Analysis of Water
D3866 Test Methods for Silver in Water
D3919 Practice for Measuring Trace Elements in Water by Graphite Furnace Atomic Absorption Spectrophotometry
D4190 Test Method for Elements in Water by Direct-Current Plasma Atomic Emission Spectroscopy
D4191 Test Method for Sodium in Water by Atomic Absorption Spectrophotometry
D4192 Test Method for Potassium in Water by Atomic Absorption Spectrophotometry
D4309 Practice for Sample Digestion Using Closed Vessel Microwave Heating Technique for the Determination of Total Metals in Water
D4691 Practice for Measuring Elements in Water by Flame Atomic Absorption Spectrophotometry
D511 Test Methods for Calcium and Magnesium In Water
D5673 Test Method for Elements in Water by Inductively Coupled Plasma-Mass Spectrometry
D857 Test Method for Aluminum in Water
D858 Test Methods for Manganese in Water
Quality Laboratory-In-Bottle Acid Digestion of Whole Water Samples
EPA-600/4-79-020 Methods for Chemical Analysis of Water and Wastes
EPA-600/R-94/111 Methods for the Determination of Metals in Environmental Samples-Supplement 1
U.S. Geological Survey Open File Report 96-225: Methods of Analysis by the U.S. Geological Survey National Water Quality Laboratory-In-Bottle Acid Digestion of Whole Water Samples

Index Terms

digestion; flame atomic absorption spectroscopy; graphite furnace atomic absorption spectroscopy; inductively coupled plasma (ICP); metals; plasma-mass spectrometry ; waste water; water; ICS Number Code 77.040.30; 77.040.30

Citing ASTM Standards

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