Page:NIOSH Manual of Analytical Methods - 7300.pdf/2

 ELEM ENT S (ICP): ME TH OD 7300, Issue 3, dated 1 5 March 2003 - Page 2 of 8 REAGENTS:

EQUIPMENT:

1. Nitric acid (HNO 3), conc., ultra pure. 2. Pe rchloric acid (H ClO 4), con c., ultra p ure.* 3. Ashing acid: 4:1 (v/v) HNO 3:HClO 4. Mix 4 volumes conc. HNO 3 with 1 volume conc. HClO 4. 4. Ca libration s tock solutions, 1000 µg/m L. Com mercially available, or prepared per instrument manufacturer's recomm endation (see step 12 ). 5. Dilution acid, 4% HNO 3, 1% HC lO 4. Add 50 mL ashing acid to 600 mL water; dilute to 1 L. 6. Argon. 7. Distilled,deionized water.

1. Sam pler: cellulose ester m em brane filter, 0.8-µm pore size; or polyvinyl chloride m em brane, 5.0-µm pore size; 37-m m diam eter, in cassette filter holder. 2. Personal sa m pling pum p, 1 to 4 L/m in, with flexible connecting tubing. 3. Inductively coupled plasma-atomic emission spectrometer, equipped as specified by the manufacturer for analysis of elements of interest. 4. Regulator, two-stage, for argon. 5. Beakers, Phillips, 125-mL, or Griffin, 50-mL, with watch glass c overs .** 6. Volum etric flasks, 10-, 25-,10 0-m L., and 1-L ** 7. Ass orted vo lum etric pipets as need ed.** 8. Hotplate, surface temperature 150 °C.



See SPECIAL PRECAUTIONS.

and rinse thoroughly in distilled water before use.
 * Clean all glasswa re with conc. nitric acid

SPECIAL PRECAUTIONS: All perchloric acid digestion s are req uired to be done in a perchloric acid hood. When working with concentrated acids, wear protective clothing and gloves.

SAMPLING: 1. Calibrate each personal sampling pump with a representative sampler in line. 2. Sa m ple at an accurately known flow rate between 1 and 4 L/min for a total sample size of 200 to 2000 L (see Ta ble 1) for T W A m eas urem ents. Do not exceed a filter loading of ap prox imately 2 m g total dust.

SAMPLE PREPARATION: 3. Open the cassette filter holders and transfer the samples and blanks to clean beakers. 4. Add 5 mL ashing acid. Cover with a watchglass. Let stand 30 min at room tem perature. NOTE: Start a reagent blank at this step. 5. Heat on hotplate (120 °C) until ca. 0.5 mL remains. NOT E 1: Recovery of lead from som e pa int m atrices m ay require other d igestion tec hniques. See Method 7082 (Lead by Flame AA S) for an alterna tive hotplate digestion procedure or Method 7302 for a microwave digestion procedure. NOTE 2: Som e species of Al, Be, Co, Cr, Li, Mn, Mo, V, and Zr will not be completely solubilized by this procedure. Alternative solubilization techniques for most of these elements can be found elsewhe re [5-1 0]. For exa m ple, aq ua re gia m ay be n eed ed fo r Mn [6,12]. 6. Add 2 m L ashing acid and repeat step 5. Rep eat this step until the solution is clear. 7. Rem ove watchg lass and rinse into the beake r with distilled water. 8. Increase the tem perature to 150 °C and take the s am ple to near dryness (ca. 0.5 m L). 9. Dissolve the residue in 2 to 3 mL dilution acid. 10. Transfer the solutions quantitatively to 25-mL volumetric flasks. 11. Dilute to volume with dilution acid. NOTE: If more sensitivity is required, the final sample volume m ay be held to 10 mL.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition