Online eluent-switching technique coupled anion-exchange liquid chromatography–ion trap tandem mass spectrometry for analysis of non-steroidal anti-inflammatory drugs in pig serum.

A novel method for online extraction, pH-gradient separation, and analysis of nine non-steroidal anti-inflammatory drugs (NSAIDs) was developed by coupling online eluent-switching technique to single anion-exchange chromatographic column/ion trap mass spectrometer (MS) and used for monitoring NSAIDs residues in pig serum. A neutral eluent and a pH-gradient eluent were used for extraction and separation of NSAIDs, respectively. Each of nine NSAIDs has an MS precursor ion of either [M−H]− or [M−Na]−.

The potential of at-home prediction of the formation of urolithiasis by simple multi-frequency electrical conductivity of the urine and the comparison of its performance with urine ion-related indices, color and specific gravity.

It is important to control daily diet, water intake and life style as well as monitor the quality of urine for urolithiasis prevention. For decades, many ion-related indices have been developed for predicting the formation of urinary stones or urolithiasis, such as EQUILs, relative supersaturation (RSS), Tiselius indices (TI), Robertson risk factor algorithms (RRFA) and more recently, the Bonn risk index. However, they mostly demand robust laboratory analysis, are work-intensive, and even require complex computational programs to get the concentration patterns of several urine analytes.

Online capillary solid-phase microextraction coupled liquid chromatography-mass spectrometry for analysis of chiral secondary alcohol products in yeast catalyzed stereoselective reduction cell culture.

An online solid-phase microextraction coupled liquid chromatography-electrospray ionization-ion trap mass spectrometry was developed for the analysis of trace R- and S-4-phenyl-2-butanol (R- and S-pbol) in salt rich cell culture of Saccharomyces cerevisiae catalyzed stereoselective reduction of 4-pheny-2-butanone (pbone). A Supel-Q PLOT capillary column was used for the extraction and deionized distilled water was used as the extraction mobile phase. The extraction flow rate and extraction time were at 0.

Development of immobilized cellulase through functionalized gold nano-particles for glucose production by continuous hydrolysis of waste bamboo chopsticks.

Cellulase immobilized on silica through the assistance of l-cysteine functionalized gold nano-particle was applied for the continuous hydrolysis of waste bamboo chopsticks powder to produce glucose. The optimal conditions for the continuous hydrolysis were pH 8.0, 50°C.

Development of online sampling and matrix reduction technique coupled liquid chromatography/ion trap mass spectrometry for determination maduramicin in chicken meat.

An online sampling and matrix reduction technique coupled liquid chromatography electrospray-ion-trap mass spectrometry was developed for rapid analysis of maduramicin (MAD) residue in chicken meat. Multiple-reaction monitoring of mass spectrometry in positive ion mode was used to detect maduramicin. A post-column continuous infusion of internal standard (nigericin) with matrix-matched calibration method was utilised for quantification.

Application of simple on-line sweeping sample concentration technique coupled micellar electrokinetic chromatography for simultaneous analysis of estrogen and androgen epimer.

A reliable, convenient, and sensitive on-line sweeping-MEKC sample concentration technique has been applied for the simultaneous separation of six steroids including two pairs of epimer with 10mM phosphate buffer (pH 7.0) that contains 80mM sodium dodecyl sulfate (SDS), 14mM β-cyclodextrin (β-CD), and 4% (v/v) methanol. The column length was 105cm (effective length, 90cm).

Simultaneous analysis of aspartame and its hydrolysis products of Coca-Cola Zero by on-line postcolumn derivation fluorescence detection and ultraviolet detection coupled two-dimensional high-performance liquid chromatography.

An innovative two-dimensional high-performance liquid chromatography system was developed for the simultaneous analysis of aspartame and its hydrolysis products of Coca-Cola Zero. A C8 reversed-phase chromatographic column with ultraviolet detection was used as the first dimension for the determination of aspartame, and a ligand-exchange chromatographic column with on-line postcolumn derivation fluorescence detection was employed as the second dimension for the analysis of amino acid enantiomers. The fluorimetric derivative reagent of amino acid enantiomers was o-phthaldialdehyde.

On-line desalting and carbohydrate analysis for immobilized enzyme hydrolysis of waste cellulosic biomass by column-switching high-performance liquid chromatography.

An innovative green column-switching high-performance liquid chromatographic (HPLC) technique was developed by coupling traditional and Pb(2+) ion-exclusion columns to study enzyme hydrolysis components of waste cellulosic biomass. Pure water was used as the mobile phase to separate neutral polar analytes in high salt content solution. The column-switching HPLC-RI was connected on-line to the immobilized enzyme reactor for successive on-line desalting and simultaneous analysis of six carbohydrates (cellobiose, glucose, xylose, galactose, mannose, and arabinose) in the hydrolysate of waste paper and waste tree branch by incorporating the heart-cut and the elution-time-difference techniques.

Analysis of steroids in yeast-mediated cell culture by on-line solid-phase extraction coupled high-performance liquid chromatography electrospray-ionization/mass spectrometry and novel continuous postcolumn infusion of internal standard technique.

The reduction of 17-ketosteroid estrone or androstenedione to corresponding 17alpha- and 17beta-estradiol or testosterone and epitestosterone has been performed with Saccharomyces cerevisiae. In the analysis of the cell culture, the solid-phase extraction (SPE) method was on-line coupled to high-performance liquid chromatography electrospray-ionization/mass spectrometry (HPLC-ESI/MS) for sample pretreatment to eliminate the complicated matrix interference and preconcentrate of the analytes before chromatographic separation. A novel quantification method with the continuous postcolumn infusion of internal standard was developed for the determination of substrate and products.

Sampling, dilution, and loading device-coupled high-performance liquid chromatography method for successive on-line analyses of major carbohydrate products in immobilized cellulase hydrolysate of paper cellulose.

A device with direct sampling, dilution, and sample loading has been utilized to couple a vertically hanging immobilized cellulase bioreactor with a high-performance liquid chromatography system to make a successful on-line analysis of the 3 major carbohydrate products: glucose, xylose, and cellobiose in the cellulase hydrolysate. The coupled analysis system for successive on-line monitoring of the enzymatic hydrolysis of paper cellulose was stable over a period of 96 h. A comparative study involving 4 different quantification methods for the 3 carbohydrates was conducted.

On-line cut-off technique and organic modifier addition aided signal enhancement for trace analysis of carbohydrates in cellulase hydrolysate by ion exclusion chromatography-electrospray ionization mass spectrometry.

Paper cellulose has been hydrolyzed with calcium alginate immobilized cellulase to produce carbohydrate products and the three trace sugars, galactose, arabinose, and mannose in the cellulase hydrolysate have been analyzed by HPIEC/ESI-MS. Applying the on-line cut-off technique to the HPIEC/ESI-MS can cut the high concentration glucose off to eliminate its interference on the peaks of minor sugars and enhance their signals from 1.1- to 1.