Page:NIOSH Manual of Analytical Methods - 7306.pdf/2

 ELEMENTS by Cellulosic Internal Capsule Sampler: METHOD 7306, Issue 1, dated 10 September 2015 - Page 2 of 11

REAGENTS: 1. 2. 3. 4. 5.

6. 7.

EQUIPMENT:

Nitric acid (HNO3)*, concentrated, Trace metal grade Hydrochloric acid (HCl)*, conc., Trace metal grade (only required if hydrochloric acid digestion is to be carried out) Perchloric acid (HClO4)*, conc., optima (only required if perchloric acid digestion is to be carried out) Calibration stock solutions, 1000 μg/L: Commercially available; or prepared per instrument manufacturer’s recommendation Dilution acid: 20% nitric acid* (7302); 4% nitric acid:1% perchloric acid* (7300); 5% aqua regia (7301)*; or 5% nitric acid: 5% hydrochloric acid* (7303) [dilution acid is dependent upon sample preparation method used] Argon, as specified by ICP-AES manufacturer Deionized water, ASTM Type II [13] or equivalent


 * See SPECIAL PRECAUTIONS

1.

Sampler: cellulose acetate internal capsule attached to mixed cellulose ester membrane filter, 0.8-μm pore size; 37-mm diameter, in 2-piece, closed-face cassette filter holder 2. Personal sampling pump, 1 to 4 L/min, with flexible connecting tubing, capable of maintaining constant flow 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 covers** 6. Volumetric flasks, 10-, 25-, 100-mL, and 1-L** 7. Assorted volumetric pipets, as needed** 8. Forceps, plastic or plastic-tipped 9. Hotplate (NIOSH 7300 or 7301), microwave oven (NIOSH 7302) or hot block (NIOSH 7303) [6-9]. 10. Centrifuge tubes, 50-mL or sized appropriately for hot block apparatus. rinse thoroughly in deionized water before use
 * Clean all glassware with conc. nitric acid and

SPECIAL PRECAUTIONS: All perchloric acid digestions must be carried out in a perchloric acid fume hood. When working with concentrated acids, wear protective clothing, safety goggles and gloves. All work should be performed with adequate ventilation for personnel and equipment. It is imperative that acid be added to water in order to avoid a violent exothermic reaction. SAMPLING: 1.

Calibrate each personal sampling pump with a representative sampler in line. NOTE: See NMAM guidance chapters for discussion on sampling. 2. Sample at an accurately known flow rate between 1 and 4 L/min (± 5%) for a total sample size of <1 to 2000 L (see Table 1) for TWA measurements. Do not exceed a sampler loading of approximately 5 mg total dust. NOTE: Filter overloading can be assessed by periodic visual checks. See NMAM guidance chapters for additional discussion on filter capacity. SAMPLE PREPARATION: 3.

Open the cassette filter holders and, using nonmetal forceps, transfer the samples and blanks to clean digestion vessels. NOTE:	Samples may not easily fit into the digestion vessels. Care must be taken to ensure no sample is lost during the placement of the samples in the digestion vessels.

NIOSH Manual of Analytical Methods (NMAM), Fifth Edition