Analysis of alkyl phosphates by extractive alkylation

Measurement of human urinary organophosphate pesticide metabolites by automated solid-phase extraction, post extraction derivatization, and gas chromatography–tandem mass spectrometry

“…A solid-phase extraction method with ion-exchange resin was reported by Lores and Bradway [18]. However, extraction of the compounds from urine was often incomplete and inconsistent [14], again resulting in high LODs.…”

“…Most of these meth- ods involve extraction of the highly polar alkyl phosphates from the urine matrix followed by derivatization and quantification. Separation of the metabolites from urine was achieved using liquid-liquid extraction [13][14][15][16][17], solid-phase extraction (SPE) [18][19][20], anion exchange [18,21], extractive derivatization [22], azeotropic distillation [23][24][25][26][27][28], or lyophilization (freeze-drying) [29][30][31][32]. Many reagents have been used to derivatize the analytes.…”

Molecularly imprinted solid phase extraction of urinary diethyl thiophosphate and diethyl dithiophosphate and their analysis by gas chromatography–mass spectrometry

“…However, due to the presence of several concomitants in the urine samples, the use of efficient extraction techniques is necessary to avoid interference problems during the derivatization and chromatographic analyses. In this way, some specific techniques can be pointed out, such as liquid-liquid extraction [6][7][8][9], solid phase extraction [10,11], ionic exchange extraction [12], extractive derivatization [13], azeotropic distillation [14][15][16] and lyophilization [17][18][19][20], among others. However, when unspecific methods are used, some concomitants may remain [14].…”

Simultaneous analytical method for urinary metabolites of organophosphorus compounds and moth repellents in general population

“…1). Recently, many analytical methods have been reported for urinary dialkylphosphates of low concentrations for monitoring exposure to organophosphorus insecticides by using gas chromatography/mass spectrometry, though in the past, gas chromatography with flame photometric detection (GC-FPD) [38][39][40][41][42][43][44][45][46][47][48][49][50] or gas chromatography with nitrogen-phosphorus selective detection (GC-NPD) [44,51] were applied for their analysis. As GC-FPD and GC-NPD are for specially detecting only compounds containing phosphorus among the metabolites, other compounds such as the phenolic metabolites resulting from parent insecticides, cannot be detected.…”