METALS in urine: METHOD 8310, Issue 2, dated 15 August 1994 - Page 2 of 5 EQUIPMENT:
REAGENTS: 1. 2. 3. 4.
5.
6. 7. 8.
Polydithiocarbamate resin, prepared as described in the APPENDIX. Nitric acid, conc.* Perchloric acid, conc.* Dissolution acid, 4:1 (v/v) HNO 3:HClO 4. Mix 4 volumes conc. HNO 3 with 1 volume conc. HClO 4.* Metals standards, 1000 µg/mL. Commercially available or prepared per instrument manufacturer's recommendations. Argon. Deionized water. Sodium hydroxide, 5 M. Dissolve 20 g NaOH in 50 mL boiled, deionized water; dilute to 100 mL. Store in a polyethylene bottle.
See Special Precautions.
1. Bottles, polyethylene, 125- or 250-mL, plastic-lined screw-cap.** 2. Inductively-coupled plasma-atomic emission spectrometer equipped for determination of elements of interest. 3. Regulator, two-stage, for argon. 4. Filtering apparatus for 50 mL liquid with 47-mm cellulose ester, 0.8-µm pore size filters. 5. Beakers, Griffin, 50-mL, with watchglass covers.** 6. pH meter and electrodes. 7. Volumetric flasks, 5- and 100-mL.** 8. Assorted volumetric pipets as needed.** 9. Hotplate, suitable for use at 100 °C. 10. Mechanical shaker. 11. Low temperature oxygen plasma asher (acid ashing may be substituted; see Step 9).
Clean all labware with detergent, soak 12 h in 10% (v/v) HNO 3, and soak 12 h in deionized water.
SPECIAL PRECAUTIONS: Concentrated acids are extremely corrosive. Work with concentrated acids only in fume hoods and wear appropriate safety equipment (safety glasses or face shield, gloves, and labcoat). Samples of urine collected from humans pose a real health risk to laboratory workers who collect and handle these samples. These risks are primarily due to personal contact with infective biological samples and can have serious health consequences, such as infectious hepatitis, and other diseases. There is also some risk from the chemical content of these samples, but this is much less. Those who handle urine specimens should wear protective gloves, and avoid aerosolization of the samples. Mouth pipetting, of course, must be avoided.
SAMPLING: 1. 2. 3.
Collect a 50-mL urine sample in a polyethylene bottle. Add 5 mL conc. HNO 3 as a preservative. Pack samples in an insulated shipping container under refrigeration (e.g., styrofoam with dry ice) for transportation to laboratory.
SAMPLE PREPARATION: 4. 5.
6. 7. 8. 9.
Perform a creatinine determination on an aliquot of the sample (e.g., [3]). Adjust the sample pH to 2.0 ± 0.1 with 5 M NaOH and then add 60 ± 10 mg polydithiocarbamate resin. NOTE: Start reagent blanks, in triplicate, at this step. Include resin and filters (step 7). Agitate samples (on the shaker) for at least 12 h. Filter samples through a 0.8-µm cellulose ester membrane filter, saving the filtrate and resin. Place the collected resin and filter in a clean 50-mL beaker. Adjust filtrate pH to 8.0 ± 0.1 with 5 M NaOH, add more resin, then repeat steps 5 and 6, combining the filters and resins from the two extractions. Ash filters and resins in a low temperature oxygen plasma asher for 6 h or until ashing is NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
