Page:NIOSH Manual of Analytical Methods - 9109.pdf/27

 METHAMPHETAMINE. . . on Wipes by SPE: METHOD 9109, Issue 1, dated 17 October 2011 - Page 27 of 33

APPENDIX: A. REAGENTS and SOLUTIONS: 1.	4,4’-Dibromooctafluorobiphenyl is optional. It is useful for monitoring instrument tuning and autosampler performance. 2.	Primary amines form Schiff bases and enamines with ketones and aldehydes. These may in turn form derivatives with the acylating reagents. The use of acetone must strictly be avoided prior to the analytes being derivatized. Glassware and equipment rinsed with acetone must be thoroughly dried. Toluene should be avoided for making up standard solutions because it usually contains benzaldehyde, an oxidation product of toluene. Condensation products have been observed between primary amines and benzaldehyde. The only solvents recommended for the preparation of stock solutions and dilutions thereof are methanol (preferably) and isopropanol. B. EQUIPMENT: 1.	Wipe media: Besides cotton gauze, 4”X4” (10 cm x 10 cm) 4-ply MIRASORB® (Johnson and Johnson), and 4”X4” (10 cm x 10 cm) AlphaWipe® (TX1004, Texwipe Corp) were acceptable wipe media and can be used in the absence of cotton gauze. MIRASORB®, a non-woven cotton/polyester blend, is discontinued but counterparts exist that claim to be of identical construction and fiber composition. AlphaWipe® is a hydrophilic, highly adsorbent, tightly knitted continuous filament polyester wipe. Precision and accuracy data for MIRASORB® are given in the Backup Data Report [2]. 2.	Shipping containers: The 50-mL polypropylene centrifuge tubes with caps are preferred for one or two gauze wipes and are not as breakable as the 40-mL VOA vials. The 40-mL VOA vials are acceptable for single gauze wipes. Larger containers (glass with a PTFE lined cap) should be used for combining more than two gauze wipes into a single sample. The size of the container for two or more wipes should be approximately 25 mL per gauze wipe (e.g., a minimum size of 100-mL for up to four gauze wipe samples). There needs to be enough extra headspace in the shipping container to allow the desorption solution to cover the gauze wipes and to percolate freely through the wipe sample(s) during mixing. 3.	Each regulatory agency having legal jurisdiction over the contaminated site may require different but specific off-site preparation and on-site sampling procedures. It is important to consult local regulatory agencies or departments of health having legal jurisdiction over contaminated sites to determine specific sampling, quality control, analyses, and reporting requirements. C. SAMPLING: 1.	Follow specific requirements of surface area to be wiped (usually 100 cm² or 1000 cm²) and action threshold (or maximum allowable residual level) set by the state or specified by the client. Uptake rates depend upon the wipe sampling method used, so the specific wipe technique used must be specified, and any deviations from the required wipe sampling requirements noted. Note:	 To ensure that samples have not been tampered with, the use of custody seals and a chainof-custody form is strongly recommended. 2.	Prepare a rigid template from disposable cardstock or a sheet of PTFE having either a 10 cm × 10 cm or 32 cm × 32 cm square-cut hole. The template must be able to retain its shape during wiping to ensure that the areas wiped were either 100 cm² or 1000 cm². Secure the template(s) to the area(s) to be wiped (e.g., with tape along outside edge of template). If a single-use disposable template is not used, clean the template between samples to avoid cross-contamination, and provide the laboratory with a blank wipe of the cleaned template between samples to determine that no crosscontamination has occurred. 3.	A template might not always be applicable, as in curved or odd-shaped areas such as around burners on stove tops or a fan blade. In such cases sample an area as close to either 100 cm² or 1000 cm² as feasible and provide the measurement to the regulatory agency and to the analytical laboratory for proper reporting. Tape can be used to delineate the sampling area. 4.	It is recommended to provide extra wipe media from the same lot for required media blanks, fieldequipment blanks, samples, and quality-control samples.

NIOSH Manual of Analytical Methods (NMAM), Fifth Edition

Method rev. 1.1.1