The use of solid-phase microextraction/gas chromatography-mass spectrometry for the determination of degradation products of volatile and semivolatile compounds

One of the more important applications in the pharmaceutical and personal c are industries is the determination of degradation products in volatile and semivolatile compounds. The conventional approaches to these studies often utilize time-consuming and labor-intensive techniques in conjunction with potentially hazardous solvents. A new approach developed in our laboratory using solid-phase microextraction (SPME) in conjunction with gas chromatogr aphy-mass spectrometry (GC/MS) to determine degradation products for volati le and semivolatile organic compounds is described. The approach was evalua ted by the measurement of diphenhydramine hydrochloride, a known over-the-c ounter (active) pharmaceutical product. Aqueous solutions of diphenhydramin e HCl were subjected to stress and subsequently examined using SPME-GC/MS. The hydrolysis degradation products benzhydrol, benzophenone, and dimethyla minoethanol were detected. Solid diphenhydramine was thermally stressed and subsequently examined by headspace SPME/GC-MS. The thermal degradation pro ducts detected were dimethylaminoethanol, diphenylmethane, diphenylchlorome thane, benzhydrol, and benzophenone. These results were in agreement with d egradation studies in the literature performed on diphenhydramine HCl using conventional approaches. SPME-GC/MS was then used to determine the acid hy drolysis degradation product for a cosmetic preservative iodopropynyl butyl carbamate (3-iodo-2-propynyl-n-butyl carbamate) also known as IPBC. SPME/G C-MS analysis of an acid-stressed IPBC solution yielded evidence of the com pound 3-iodo-2-chloro-2-propenyl-n-butyl carbamate, indicative of addition of HCl across the triple bond of IPBC. (C) 2001 John Wiley & Sons, Inc.