PMID- 27599798 OWN - NLM STAT- MEDLINE DCOM- 20161221 LR - 20181202 IS - 1873-3778 (Electronic) IS - 0021-9673 (Linking) VI - 1465 DP - 2016 Sep 23 TI - Poly(N-vinylcarbazole-co-divinylbenzene) monolith microextraction coupled to liquid chromatography-high resolution Orbitrap mass spectrometry to analyse benzodiazepines in beer and urine. PG - 55-62 LID - S0021-9673(16)31154-2 [pii] LID - 10.1016/j.chroma.2016.08.064 [doi] AB - A poly(N-vinylcarbazole-co-divinylbenzene) (NVC/DVB) monolithic column was successfully prepared in a silanized capillary for microextraction of six benzodiazepines (BZPs) in complex samples. The polymerization was optimized primarily by changing the ratio of porogen content. The optimized polymer monolith had a homogeneous and continuous column bed, good permeability and mechanical stability. Poly(NVC/DVB) had good affinity to BZPs because of its through-pore structure and strong pi-pi stacking interactions derived from the rich benzene functional groups in the polymer. Potential factors that affect the extraction efficiency were studied in detail. In the optimized method, 3mL of sample (pH 2) was extracted with the polymer monolithic column and eluted with 80muL of methanol, and the eluent was analysed with ultra-high-performance liquid chromatography and quadrupole high resolution Orbitrap mass spectrometry (UHPLC/Q-Orbitrap MS). Under these conditions, the developed method gave the linear range of 0.005-0.5ng/mL for most of the six BZPs, whereas 0.05-0.5ng/mL for nitrazepam, 0.01-0.5ng/mL for lorazepam, respectively, with coefficients of determination (R(2))>/=0.9991. The detection limits (LODs) were 1.08-6.04ng/L, and the quantification limits (LOQs) were 3.60-20.1ng/L. The method repeatability was investigated in terms of intra- and inter-day precision, which were indicated by relative standard deviations (RSDs) of