LAUSR

A few years ago while investigating the GC-MS method for bisphenol S (BPS) in order to expand our existing GCMS method for bisphenol A (BPA) to other bisphenols, it was observed that the work on BPS reported by Viñas et al. in 2010 [1] may not be factually correct. Unlike the LC-MS methods where BPS is very often the first bisphenol eluted from the column, for GC-based methods, BPS will elute from the column much later (after BPA). In the work of Viñas et al. [1], two derivatization methods were investigated: derivatization with acetic anhyd r id e (AA) and de r i va t i z a t i on wi t h N ,O Bis(trimethylsilyl)trifluoroacetamide (BSTFA). BPS eluted before BPA from their GC column SLB-5MS (30 m × 0.25 mm i.d., 0.25-μm film thickness) for both derivatization methods, with retention times of 9.26 min (BSTFA) and 9.36 min (AA) for BPS, and 10.09 min (BSTFA) and 10.65 min (AA) for BPA. Using an equivalent GC column (Agilent DB-5MS, 30 m × 0.25 mm i.d., 0.25-μm film thickness) to the SLB-5MS column used by Viñas et al. [1], our results show that BPS is the last bisphenol eluted