National Institute for Occupational Safety and Health

Name: NIOSH Manual of Analytical Methods — Lead by Flame AAS (7082)
Author: National Institute for Occupational Safety and Health

NIOSH Manual of Analytical Methods… (1994)

Summary

“NIOSH Manual of Analytical Methods — Lead by Flame AAS (7082)”, published in 1994, is a work by National Institute for Occupational Safety and Health. It explores elements such as sample, microwave and mL.

Quotes from NIOSH Manual of Analytical Methods… (National Institute for Occupational Safety and Health)

National Institute for Occupational Safety and Health, NIOSH Manual of Analytical Methods… (1994)

“ Method 7082, Issue 2, dated 15 August 1994 - Page 6 of 7 or 12 sample vessels. Any vessels containing 5 mL of nitric acid for reagent blank purposes are counted as sample vessels. When fewer than the recommended number of samples are to be digested, i.e., three samples plus one blank, the remaining vessels should be filled with 5 mL of nitric acid to achieve the full complement of vessels. This provides an energy balance since the microwave power absorbed is proportional to the total mass in the cavity [14] . ”

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National Institute for Occupational Safety and Health, NIOSH Manual of Analytical Methods… (1994)

“ Microwave apparatus requirements a. The microwave unit provides programmable power with a minimum of 574 W and can be programmed to within ± 10 W of the required power. b. The microwave unit cavity is corrosion resistant as well as ventilated. All electronics are protected against corrosion for safe operation. c. The system requires Teflon PFA digestion vessels (120-mL capacity) capable of withstanding pressures up to 7.5 ± 0.7 atm (110 ± 10 psi) and capable of controlled pressure relief at pressures exceeding 7.5 ± 0.7 atm (110 ± 10 psi) . ”

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National Institute for Occupational Safety and Health, NIOSH Manual of Analytical Methods… (1994)

“ All references to water in the method refer to reagent water that meets the ASTM Type 2 standard. Procedure 1. Calibration of Microwave Equipment Calibrate microwave equipment in accordance with manufacturer's instructions. If calibration instructions are not available, see EPA Method 3051 [11] . 2. All digestion vessels and volumetric ware must be carefully acid washed and rinsed with reagent water. All digestion vessels should be cleaned by leaching with hot (1:1) nitric acid for a minimum of fifteen minutes, rinsed with reagent water, and dried in a clean environment. 3. Sample Digestion a. ”

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Source: Wikisource

National Institute for Occupational Safety and Health, NIOSH Manual of Analytical Methods… (1994)

“ Tare the Teflon PFA digestion vessel. b. Weigh out 0.1 g paint chip sample to the nearest 0.001 g into the tared Teflon PFA sample vessel. 2 With large paint chip samples, measure out a 2 cm piece, weigh to the nearest 0.001 g, and quantitatively transfer it to the vessel. c. Add 5.0 ± 0.1 mL concentrated nitric acid to the sample vessel in a fume hood. If a vigorous reaction occurs, allow the reaction to stop before capping the vessel. ”

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Source: Wikisource

National Institute for Occupational Safety and Health, NIOSH Manual of Analytical Methods… (1994)

“ Concentrated nitric acid is an irritant and may burn skin. Perform all acid digestions in a fume hood. Hydrogen peroxide is a strong oxidizing agent, a strong irritant, and corrosive to the skin. Wear gloves and eye protection. SAMPLING: 1. 2.
Calibrate each personal sampling pump with a representative sampler in line. Sample at an accurately known flow rate between 1 and 4 L/min for up to 8 h for a total sample size of 200 to 1500 L for TWA measurements. Do not exceed a filter loading of ca. ”

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Source: Wikisource

National Institute for Occupational Safety and Health, NIOSH Manual of Analytical Methods… (1994)

“ Use D2 or H2 continuum or Zeeman background correction to control flame or molecular absorption. High concentrations of calcium, sulfate, carbonate, phosphate, iodide, fluoride, or acetate can be corrected. ”

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Source: Wikisource

National Institute for Occupational Safety and Health, NIOSH Manual of Analytical Methods… (1994)

“ A safety concern relates to the useof sealed containers without pressure relief valves in the unit. Temperature is the important variable controlling the reaction. Pressure is needed to attain elevated temperatures but must be safely contained [12] . f. Polymeric volumetric ware in plastic (Teflon or polyethylene) , 50- or 100-mL capacity. g. Disposable polypropylene filter funnel. h. Analytical balance, 300-g capacity, and minimum ± 0.001 g. Reagents 1. Nitric acid, concentrated, spectroscopy grade. 2. Reagent Water. Reagent water shall be interference free. ”

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Source: Wikisource

National Institute for Occupational Safety and Health, NIOSH Manual of Analytical Methods… (1994)

“ Prepare a series of working standards covering the range 0.25 to 20 μg/mL Pb (2.5 to 200 μg Pb per sample) . a. Add aliquots of calibration stock solution to 100-mL volumetric flasks. Dilute to volume with 10% HNO3. Store the working standards in polyethylene bottles and prepare fresh weekly. b. Analyze the working standards together with the blanks and samples (steps 14 and 15) . c. Prepare a calibration graph of absorbance vs. solution concentration (μg/mL) . 12. Aspirate a standard for every 10 samples to check for instrument drift. 13. ”

National Institute for Occupational Safety and Health

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Quotes from NIOSH Manual of Analytical Methods… (National Institute for Occupational Safety and Health)

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