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METALS in urine: METHOD 8310, Issue 2, dated 15 August 1994 - Page 3 of 5

10. 11.

complete (200 watts at 1 to 2 torr, or manufacturer's recommendations). NOTE: Steps 5 to 10 of Method 7300 (Elements by ICP), an HNO 3/HClO 4 digestion, may be substituted for the low temperature oxygen plasma ashing. Use a final solution volume of 5.0 mL (step 11). Add 0.5 mL dissolution acid and warm on a hotplate (15 min at 50 °C). Transfer solutions quantitatively to 5-mL volumetric flasks and dilute to volume with distilled deionized water.

CALIBRATION AND QUALITY CONTROL: 12. 13. 14.

Calibrate the spectrometer according to manufacturer's recommendations. NOTE: Typically, an acid blank and 10 µg/mL multi-element solutions are used. Analyze a standard for every 10 samples. Check measurement recoveries with at least three spiked unexposed urine samples per 10 samples. NOTE: For urine spikes, split a 100-mL control urine sample and analyze 50 mL without spiking. Subtract the metal quantity found in the unspiked portion from the metal quantity found in the spiked portion in order to determine measurement recovery.

MEASUREMENT: 15. 16.

Set the spectrometer to conditions specified by the manufacturer. Analyze standards and samples. NOTE: If the values for the samples are above the range of the standards, dilute the sample solutions with 1 volume dissolution acid plus 9 volumes deionized water, reanalyze, and apply the appropriate dilution factor in the calculations.

CALCULATIONS: 17. 18.

19.

Obtain the solution concentration for the sample, C s (µg/mL), and the average blank, C b (µg/mL), from the analyses data. Using the solution volumes of sample, V s (mL), and blank, V b (mL), calculate the concentration, C (µg/mL), of each element in the volume of urine collected, V (L):

Report the results as µg metal/g creatinine.

GUIDELINES TO INTERPRETATION: Acceptable and unacceptable levels for metals have not been determined by this method. Lauwerys [4] discusses metals and can be consulted for guidance and interpretation.

EVALUATION OF METHOD: Recovery of these 16 metals from spiked urine samples are shown in Table 2 (recoveries ranged from 77 to 100%). The precisions determined for the various elements are also given in Table 2 [1].

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94

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