National Institute for Occupational Safety and Health

Name: NIOSH Manual of Analytical Methods — Volatile Organic Compounds (Screening) (2549)
Author: National Institute for Occupational Safety and Health

NIOSH Manual of Analytical Methods… (1994)

Summary

“NIOSH Manual of Analytical Methods — Volatile Organic Compounds (Screening) (2549)”, published in 1994, is a work by National Institute for Occupational Safety and Health. It explores elements such as thermal desorption, sample and analytes.

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)

“ Keep field blanks capped at all times. Tubes can act as diffusive samplers if left uncapped in a contaminated environment. Collect a "humidity test" sample to determine if the thermal adsorption tubes have a high water background. NOTE: At higher sample volumes, additional analyte and water (from humidity) may be collected on the sampling tube. At sufficiently high levels of analyte or water in the sample, the mass spectrometer may malfunction during analysis resulting in loss of data for a given sample. Collect a "control" sample. ”

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Source: Wikisource

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

“ Under no circumstances should tape or labels be applied directly to the thermal desorption tubes. Calibrate each personal sampling pump with a representative sampler in line. Remove the caps of the sampler immediately before sampling. Attach sampler to personal sampling pump with flexible tubing. NOTE: With a multi-bed sorbent tube, it is extremely important to sample in the correct direction, from least to maximum strength sorbent. For general screening, sample at 0.01 to 0.05 L/min for a maximum sample volume of 6 L. Replace caps immediately after sampling. ”

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Source: Wikisource

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

“ Prepare stock solutions by adding known amounts of analytes to 10-mL volumetric flasks containing high purity solvent (carbon disulfide, methanol, toluene) . Solvents are chosen based on solubility for the analytes of interest and ability to be separated from the analytes when chromatographed. Highly volatile compounds should be dissolved in a less volatile solvent. For most compounds, carbon disulfide is a good general purpose solvent, although this will interfere with early eluting compounds. ”

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Source: Wikisource

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

“ After the bulb has been stirred and cooled to room temperature, remove aliquots from the bulb with a gas syringe and inject into a sample tube as described below. Tube spiking: Fit a GC injector with a 1⁄4" column adapter. Maintain the injector at 120 C to assist in vaporization of the injected sample. Attach cleaned thermal desorption tubes to injector with 1⁄4” Swagelok nuts and Teflon ferrules, and adjust helium flow though the injector to 50 mL/min. Attach the sampling tube so that flow direction is the same as for sampling. ”

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Source: Wikisource

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

“ If carryover is observed, make additional blank runs until the contamination is flushed from the thermal desorber system. 13. Maintain a log of thermal desorber tube use to record the number of times used and compounds found. If unexpected analytes are found in samples, the log can be checked to verify if the tube may have been exposed to these analytes during a previous sampling use. 14. Run spiked samples along with the screening samples to confirm the compounds of interest. ”

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Source: Wikisource

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

“ Precautions should be taken to avoid inhalation of the vapors from solvents as well. Skin contact should be avoided. SAMPLING: NOTE:
1. 2.
3.
4.
5. 6.
Prior to field use, clean all thermal desorption tubes thoroughly by heating at or above the intended tube desorption temperature for 1-2 hours with carrier gas flowing at a rate of at least 50 mL/min. Always store tubes with long-term storage caps attached, or in containers that prevent contamination. Identify each tube uniquely with a permanent number on either the tube or tube container. ”

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Source: Wikisource

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

“ One of the primary differences in these methods is the sorbents used in the thermal desorption tubes.
NIOSH Manual of Analytical Methods (NMAM) , Fourth Edition, 5/15/96 VOLATILE ORGANIC COMPOUNDS (SCREENING) : METHOD 2549, Issue 1, dated 15 May 1996 - Page 2 of 8
REAGENTS:
EQUIPMENT:
1. Air, dry 2. Helium, high purity 3. Organic compounds of interest for mass spectra verification (See Table 1) .* 4. Solvents for preparing spiking solutions: carbon disulfide (low benzene chromatographic grade) , methanol, etc. ”

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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