Simultaneous determination of the lipophilicity and dissociation constants of dialkyl phosphinic acids by negligible depletion hollow fiber membrane-protected liquid-phase microextraction.

摘要: Abstract Determination of the physicochemical properties, especially lipophilicity (expressed as logarithm distribution coefficient, log D) and dissociation constant (pKa), is great importance in early stage environmental risk assessment for an ionizable compound without these data. Currently, D pKa values dialkyl phosphinic acids (DPAs), hydrolysates aluminum phosphinates (ADPs) that one class emerging phosphorus-containing flame retardants, are not available. In this study, three DPAs including methylethylphosphinic acid (MEPA), diethylphosphinic (DEPA) methylcyclohexyl (MHPA), were simultaneously determined by negligible depletion hollow fiber supported liquid phase microextraction (nd-HF-LPME) followed ultra-performance chromatography coupled with tandem mass spectrometry (UPLC–MS/MS). The curve-fitting experimental data equations derived on basis Henderson-Hasselbalch equation compared model calculated For MEPA, DEPA MHPA, close around 3, but Ds strongly pH-dependent from −5.01 to 1.01. KOW neutral form (log KOW,HA) ionic (log KOW,A) range −0.67–1.02 −3.86–−1.33, respectively. experimentally highly good agreement ACD/pKa predicted measured KOW,HA closely related KOWWIN ones, suggesting alternative methods estimate DPAs, As far we know, first report which fundamental product design evaluating behavior effects ADPs.