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A monolithic column with high-performance liquid chromatography coupled with an ultraviolet detector was investigated for the determination of ochratoxin A in poultry feed. A systematic study was performed using solid phase extraction with a C-18 cartridge for sample pretreatment with three solvent systems. Ethyl acetate:methanol:formic acid (95:5:0.5) was found to be the most suitable. Pretreated samples were injected separately into packed and monolithic columns. The effects of the mobile phases on the chromatographic figures of merits were evaluated. Better peak symmetry, improved separation, and more theoretical plates were observed using an acetonitrile:water:formic acid (99:99:2) mobile phase. The repeatability and accuracy of the method were statistically evaluated and found to be satisfactory with a limit of detection of 40 mu gL(-1). The use of a monolithic column in conjunction with sample pretreatment provided good results for the determination of ochratoxin A in poultry feed.

This paper reports a rapid, simple, and sensitive method for determination of vitamin D3, vitamin E acetate, and vitamin K1 in plasma using atmospheric pressure chemical ionization –high performance liquid chromatography–mass spectrometry. Plasma samples were prepared using solid phase extraction. The separation of compounds was achieved using a C18 monolithic column and a mobile phase composed of methanol and 0.1% formic acid in gradient elution mode at a flow rate of 1.0 mL min−1. Analytes were ionized using atmospheric chemical ionization in positive mode. Mass spectra were recorded at m/z = 385.23, 473.47, and 451.41 for vitamin D3, vitamin E, and vitamin K1, respectively. Vitamin D2 was used as an internal standard and its mass spectra was recorded at 397.28 m/z. The method was validated using ICH guidelines. The system suitability responses were calculated for retention time, number of theoretical plates, capacity factor, resolution, and the selectivity factor. System validation was evaluated for pr...

Liquid chromatography-mass spectrometry (LC-MS) in atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) modes were studied for a multi-component plasma and urine quantification of 5 antihyperglycemic agents (metformin, pioglitazone, gliclazide, glibenclamide, and glimperide). The separation of the compounds was achieved using Chromolith Performance RP-18e column (100 × 4.6 mm), with gradient mobile phase composition of acetonitrile −0.1% formic acid. MS parameters for APCI and ESI were optimized individually and were operated in positive mode. The detection limits for the metformin, pioglitazone, glibenclamide, and glimepiride were determined to be 6.84, 6.22, 13.03, and 44.38 ng mL−1 using LC-ESI-MS; and for LC-APCI-MS, it was determined to be 48.39, 8.02, 17.02, and 144.55 ng mL−1, respectively. Gliclazide was the only exception as it exhibited a lower limit of detection (LOD) using APCI than ESI which was found to be 5.61 and 23.43 ng mL−1, respectively. The method was vali...