ASTM D4691 - 11 standard practice for measuring elements in water by flame atomic absorption spectrophotometry
Elemental constituents in water and wastewater need to be identified to support effective water quality monitoring and control programs. Currently, one of the most widely used and practical means for measuring concentrations of elements is by atomic absorption spectrophotometry.
The major advantage of atomic absorption over atomic emission is the almost total lack of spectral interferences. In atomic emission, the specificity of the technique is almost totally dependent on monochromator resolution. In atomic absorption, however, the detector sees only the narrow emission lines generated by the element of interest.
1.1 This practice covers general considerations for the quantitative determination of elements in water and waste water by flame atomic absorption spectrophotometry. Flame atomic absorption spectrophotometry is simple, rapid, and applicable to a large number of elements in drinking water, surface waters, and domestic and industrial wastes. While some waters may be analyzed directly, others will require pretreatment.
1.2 Detection limits, sensitivity, and optimum ranges of the elements will vary with the various makes and models of satisfactory atomic absorption spectrometers. The actual concentration ranges measurable by direct aspiration are given in the specific test method for each element of interest. In the majority of instances the concentration range may be extended lower by use of electrothermal atomization and conversely extended upwards by using a less sensitive wavelength or rotating the burner head. Detection limits by direct aspiration may also be extended through sample concentration, solvent extraction techniques, or both. Where direct aspiration atomic absorption techniques do not provide adequate sensitivity, the analyst is referred to Practice D3919 or specialized procedures such as the gaseous hydride method for arsenic (Test Methods D2972) and selenium (Test Methods D3859), and the cold vapor technique for mercury (Test Method D3223).
1.3 Because of the differences among various makes and models of satisfactory instruments, no detailed operating instructions can be provided. Instead the analyst should follow the instructions provided by the manufacturer of a particular instrument.
1.4 The values stated in either SI or inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
1.5 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. For specific hazard statements see Section 9.
2. Referenced Documents (purchase separately)
D1129 Terminology Relating to Water
D1192 Guide for Equipment for Sampling Water and Steam in Closed Conduits
D1193 Specification for Reagent Water
D2972 Test Methods for Arsenic in Water
D3223 Test Method for Total Mercury in Water
D3370 Practices for Sampling Water from Closed Conduits
D3859 Test Methods for Selenium in Water
D3919 Practice for Measuring Trace Elements in Water by Graphite Furnace Atomic Absorption Spectrophotometry
D4453 Practice for Handling of Ultra-Pure Water Samples
D5810 Guide for Spiking into Aqueous Samples
D5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis
E178 Practice for Dealing With Outlying Observations
E520 Practice for Describing Photomultiplier Detectors in Emission and Absorption Spectrometry
E863 Practice for Describing Atomic Absorption Spectrometric Equipment
atomic absorption spectrophotometry; flame: Absorption--spectrochemical instrumentation; Calibration--water analysis instrumentation; Direct aspiration spectrophotometric procedure; Inorganic compounds--water; Organic compounds--water; Radiation exposure--electronic components/devices; Sampling water analysis applications; Smith-Hieftje System; Spectrophotometry--atomic absorption (water/wastewater); Trace elements--water analysis; Wastewater testing/treatment; Zeeman correction;
ICS Number Code 13.060.50 (Examination of water for chemical substances)
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