Trace-level quantification of ethylene oxide and 2-chloroethanol in low-viscosity hydroxypropyl methylcellulose with solid phase microextraction and GC-MS

Ethylene oxide (EtO) is naturally present in numerous food products but recently EtO and its degradation product of 2-chloroethanol (2-CE) have been reported in amounts exceeding the maximum residue limit in Europe. The reports include hard capsules for dietary supplements made from low viscous hydroxypropyl methylcellulose (HPMC). The European council (EC) has proposed a generalized method for spices, seeds, and capsules utilizing QuEChERS, solid phase extraction (SPE), and GC-MS/MS to accommodate the need for analyte specificity, trace-level analysis, and higher throughput. HPMC has unique solvation properties and, without care, can potentially be transferred to the instrument. The current work presents the development of two methods specific for EtO and 2-CE in low viscous HPMC using solid phase microextraction (SPME) and GC-MS. Method optimization for solvation, SPME settings, and GC-MS settings are presented along with validation based on standard addition. Both methods present a high degree of specificity and limits of detection (EtO 6.7 µg/kg and 2-CE 12 µg/kg), comparable to those obtained with the EC method. Apart from sampling, the methods were fully automated and rely on low cost GC-MS instrumentation, widely available. Analyzed samples did not contain EtO or 2-CE, and method development was done with spiked samples. Contamination from plastic containers and analytical carry-over are shown as possible sources of EtO and 2-CE.