N-Alkyl-2-pyrrolidones (N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone), vapour [Air Monitoring Methods, 2014a]

Abstract

This analytical method is a validated measurement procedure for the determination of gaseous N‐methyl‐2‐pyrrolidone (NMP) and N‐ethyl‐2‐pyrrolidone (NEP) and for monitoring their Occupational Exposure Limits (OELs) or MAK values at workplaces. Both personal and stationary sampling can be performed for assessment of workplaces. Sampling is performed by drawing air through an ADS‐type silica gel tube using a suitable flow‐regulated pump with a volumetric flow rate of 20 L/h. Gaseous NMP and/or NEP are adsorbed onto the silica gel. For sample preparation the collected NMP and/or NEP are desorbed from the silica gel with a potassium hydroxide solution in methanol. The sample solutions are analysed by gas chromatography using a nitrogen‐selective detector (NPD) with dibutylamine as internal standard. The quantitative determination is based on calibration functions obtained by means of multiple‐point calibrations. The limit of quantification (LOQ) for both, NMP and NEP is 1.6 µg/mL (absolute 1.6 ng), which corresponds to a relative LOQ of 0.1 mg/m3 based on an air sample volume of 40 L.