Chip-Based Solid-Phase Extraction Pretreatment for Direct Electrospray Mass Spectrometry Analysis Using an Array of Monolithic Columns in a Polymeric Substrate
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- 作者：Aimin Tan ; Salete Benetton ; and Jack D. Henion
- 刊名：Analytical Chemistry
- 出版年：2003
- 出版时间：October 15, 2003
- 年：2003
- 卷：75
- 期：20
- 页码：5504 - 5511
- 全文大小：169K
- 年卷期：v.75,no.20(October 15, 2003)
- ISSN：1520-6882
文摘
An array of eight porous monolithic columns, preparedin a Zeonor polymeric chip by UV-initiated polymerizationof butyl methacrylate and ethylene dimethacrylate, wastested for solid-phase extraction (SPE) cleanup of biological samples prior to directly coupled electrospray massspectrometry (ESI-MS). The chip, fabricated by hot embossing and thermal bonding, consists of eight parallelchannels (10 mm long, 360 
m i.d.) connected viaexternal fused-silica capillaries. The monomer mixturewas aspirated simultaneously into the eight channelsusing a homemade vacuum manifold device and polymerized in parallel for 20 min under UV irradiation. Theporous monolithic columns were then characterized byscanning electron microscopy and evaluated by ESI-MSapplications with respect to sample capacity, recovery,reproducibility of peak area or peak height ratios, andlinearity between peak height ratio and concentrationusing imipramine as a pharmaceutical test compound.The average sample capacity was estimated to be 0.30 gwith a relative standard deviation (RSD) of 26.5% for theeight monolithic columns on the same polymeric chip. Fortwo chips prepared using the same monomer mixture, thedifference in average sample capacity was 7.0%. Theaverage recovery for the eight monolithic SPE columnson the same chip was 79.1% with an RSD of 7.9%. Usingimipramine-d3 as an internal standard, the RSD of peakheight ratios for the eight different columns was 2.0% fora standard solution containing 1 g/mL imipramine. Alinear calibration curve (R2 = 0.9995) was obtained forstandard aqueous solutions of imipramine in the rangefrom 0.025 to 10 g/mL. To demonstrate the analyticalpotential of the chip-based SPE system, two different typesof real-world samples including human urine sample andP450 drug metabolism incubation mixture were tested.Similar to standard aqueous solution, a linear correlation(R2 = 0.9995) was also found for human urine samplespiked with imipramine in the range of 0.025-10 g/mL. When aliquots of a human urine sample spiked with1 g/mL imipramine were loaded onto eight differentmonolithic columns, the RSD of peak height ratios was3.8%. For a P450-imipramine incubation mixture, theformation of the N-demethylated metabolite (m/z 267.2)and the monohydroxylated metabolite (m/z 297.2) ofimipramine was observed following chip-based monolithicSPE sample cleanup and preconcentration.
m i.d.) connected viaexternal fused-silica capillaries. The monomer mixturewas aspirated simultaneously into the eight channelsusing a homemade vacuum manifold device and polymerized in parallel for 20 min under UV irradiation. Theporous monolithic columns were then characterized byscanning electron microscopy and evaluated by ESI-MSapplications with respect to sample capacity, recovery,reproducibility of peak area or peak height ratios, andlinearity between peak height ratio and concentrationusing imipramine as a pharmaceutical test compound.The average sample capacity was estimated to be 0.30 gwith a relative standard deviation (RSD) of 26.5% for theeight monolithic columns on the same polymeric chip. Fortwo chips prepared using the same monomer mixture, thedifference in average sample capacity was 7.0%. Theaverage recovery for the eight monolithic SPE columnson the same chip was 79.1% with an RSD of 7.9%. Usingimipramine-d3 as an internal standard, the RSD of peakheight ratios for the eight different columns was 2.0% fora standard solution containing 1 g/mL imipramine. Alinear calibration curve (R2 = 0.9995) was obtained forstandard aqueous solutions of imipramine in the rangefrom 0.025 to 10 g/mL. To demonstrate the analyticalpotential of the chip-based SPE system, two different typesof real-world samples including human urine sample andP450 drug metabolism incubation mixture were tested.Similar to standard aqueous solution, a linear correlation(R2 = 0.9995) was also found for human urine samplespiked with imipramine in the range of 0.025-10 g/mL. When aliquots of a human urine sample spiked with1 g/mL imipramine were loaded onto eight differentmonolithic columns, the RSD of peak height ratios was3.8%. For a P450-imipramine incubation mixture, theformation of the N-demethylated metabolite (m/z 267.2)and the monohydroxylated metabolite (m/z 297.2) ofimipramine was observed following chip-based monolithicSPE sample cleanup and preconcentration.