Determination of cyclic organic acid anhydrides in air using gas chromatography. Part 2. Sampling and determination of hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, tetrahydrophthalic anhydride and octenylsuccinic anhydride

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Abstract
Methods for sampling and determination of four organic acid anhydrides are described. The methods were validated in a standard atmosphere and in the work environment. Hexahydrophthalic anhydride (HHPA), methylhexahydrophthalic anhydride (MHHPA), tetrahydrophthalic anhydride (THPA) and octenylsuccinic anhydride (OSA) were sampled using Tenax and Amberlite XAD-2 solid sorbents and determined by GC with flame ionization detection (FID) after elution. The precision was normally better than 10% but for OSA it was up to 19%. The detection limits were 0.1 µg per sample. MHHPA, THPA and OSA were also sampled using bubblers containing aqueous sampling solutions. MHHPA and THPA was derivatized with pentafluorobenzyl bromide (PFBBr) and determined by GC with MS detection. OSA was derivatized by methanol with boron trifluoride catalysis and determined by GC–FID. The precisions for MHHPA and THPA were 4 and 8%, respectively, and the detection limit was < 0.005 µg per sample. The precision for OSA was up to 58% and the detection limit was 0.2 µg per sample. HHPA and MHHPA were also sampled on glass-fibre filters, derivatized with PFBBr, and determined by GC–MS with good results. However, further validations of the filter methods are needed.