Page:NIOSH Manual of Analytical Methods - 5525.pdf/3

 ISOCYANAT ES, TOTA L (MAP): METHO D 5525, Issue 1, dated 15 March 2003 - Page 3 of 17

SPECIAL PRECAUTIONS: Diisocyanates are highly toxic and known respiratory irritants. Follow manufacturer’s guidelines when handling pure products. Follow hazardous material shipping requirements when transporting. Preparation of urea derivatives, samples, and standards should be don e in a h ood to avo id exp osu re to iso cyanate and s olven t vapo rs. T oxicity of MA P is unknow n. Acetic anhydride is a severe irritant; acetonitrile is flamm able and an irritant. Methylene chloride is an irritant and suspected carcinogen. Methanol is toxic and flamm able. Strong acids are toxic and corrosive. Triethylamine is toxic and corrosive.

SAMPLING: NOT E 1: Use sampling conditions listed below for the sampler selected: glass fiber filter (1); impinger (2); impinger followed by glass fiber filter (3). See Table 3 for examples of exposure scenarios and which sampler to choose. Refer to the chapter on isocyanates [1] for more detailed informa tion on how to choos e the appropriate sam pler. NOT E 2: Field controls are made by sampling in an area near the analyte sampling location but where one would not expect to find analyte. These samplers are then treated exactly like the samples from this po int on. NOT E 3: Fie ld blanks are samplers handled exactly th e sam e as sam ples except tha t no air is drawn through them. 1. Filter sampling a. Calibrate each sampling pump with a representative sampler in line. NOTE: W hen sampling aerosol with aerodynamic diameter >20 µm, an IOM sam pler with stainless stee l cassette or other su itable inhalable sam pler shou ld be u sed [1,2]. b. Attach filter cassette to sampling pump with flexible tubing. c. Sam ple at a rate of 1 to 2 L/min (2 L/min for the IOM) for a total sample of at least 1 L. d. Im m ediate ly after sampling, place filter in a wide-mouth jar with a PTFE-lined screw c ap c onta ining 5.0 mL of 1 x 10 -4 M M AP in ace tonitrile. Secure sc rew cap with a s ealing ban d. NOTE 1: If an IOM sam pler is use d, plac e en tire stainless steel cassette and filter in the jar with 10.0 m L of e xtrac ting so lution ins tead of 5.0 m L, rec ap a nd s wirl to we t all surfa ces of the IOM sam pler. NOT E 2: If co llec ting vapo r-o nly s amples, since in-field extraction is not necessary, ship the unextracted samplers with ice packs to the lab for analysis. e. Store samples in a refrigerator and ship the samples with ice packs. f. Obta in a bulk sam ple (at least 3 mL) and a Mate rial Safety Data Sheet (M SD S) for pro ducts used in the process giving rise to expos ure (e.g., for a two-part polyurethan e co ating s ystem, a sam ple of both the isocyanate product and the polyol product). These bulk samples are necessary for oligomer analysis. Ship bulks in a separate container from the air samples. g. Obta in a minimum of three field controls and three fie ld blanks per sam ple set or at least one fie ld control and one field blank for every ten sam ples. T hese controls and blanks are necessary for distinguishing be twee n artifacts a nd iso cyanates. 2. Impinger sampling a. Calibrate each sampling pump with a representative sampler in line. b. Transfer 15.0 mL of 1 x 10 -4 M MAP in purified butyl benzoate to each impinger and connect impinger to sampling pump with flexible tubing that is free of phthalate plasticizer (Fluran TM tubing is acceptable, PVC tubing is not.) c. Sam ple at 1 L/min for a total sample of at least 1 L. d. Using a disposable pipet, transfer the entire conte nts of the impinger to a 20-mL vial with a PTFE-lined screw cap. Secure screw cap with sealing band. e. Store samples in a refrigerator and ship the samples with ice packs. f. Obtain bulk sa m ples and M SDS s as des cribed in step 1.f. g. Obta in a m inim um of three field controls and three fie ld blanks per sam ple set or at least one fie ld control and one field blank for every ten samples. These controls and blanks are necessary for distinguishing be twee n artifacts a nd iso cyanates.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition