In medical practices, the determination of enantiomeric ratio of the chiral drugs is very important for their activities, bioavailabilities and biodegradation. Only homochiral medication is safe for humans. The chiral analysis in biological samples is the first and most important step. The present article describes the technical strategies of the enantiomeric resolution of racemic drugs in biol...

In this investigation, sensitive and reproducible methods are described for quantitative determination of deflazacort in the presence of its degradation product. The method was based on high performance liquid chromatography of the drug from its degradation product on reverse phase using Acquity UPLC BEH C18 columns (1.7 µm, 2.1 mm × 150 mm) using acetonitrile and water (40:60 V/V) at a flow ra...

We describe a reversed-phase HPLC method for determination of total mycophenolic acid (MPA), its free concentration (MPAf), and the glucuronide metabolite (MPAG), based on simple sample preparation and gradient elution chromatography. The compounds were quantified in parallel by absorbance at 254 nm and 215 nm in the internal standard mode. Linearity was verified up to 50 mg/L for MPA and up to...

This review describes the role of wood extractives, especially fatty and resin acids, in papermaking, as well as the importance of their removal from process waters. One of the main aims is also to illustrate versatile analysis methods for this purpose and highlight recent developments in corresponding applications. Most of the current methods require timeconsuming and laborious sample pretreat...

In a previous communication [l] we reported a procedure for the serum determination of midazolam using gas chromatography (GC) with a nitrogenselective detector. GC with nitrogen-selective detection resulted in a selective procedure for the direct determination of midaxolam with a sensitivity of 50 ng/ml. We present, in this paper, a procedure for the direct determination of midazolam and its m...

The use of antibodies in HPLC columns for on-line immunoextraction combined with reversed-phase liquid chromatography (RPLC) is of growing interest in environmental and agricultural analysis. This technique is typically performed by using a small RPLC precolumn to capture and concentrate analytes as they elute from the immunoextraction column; however, there is little information on the conditi...

The selectivity tuning of two columns coupled in series is investigated in chiral high-performance liquid chromatography. Two columns with reversal enantioselectivities [(R,R) Whelk-O 1 and (S,S) Whelk-O 1] are coupled in series via a T connector. Selectivity of such a column series is tuned by varying the mobile phase flows in the individual columns. The flow ratio necessary for the required s...

1. Stabler, T. V., and Siegel, A. L., Rapid liquid-chromatographic/fluorometric method for taurine in biological fluids, involving prederivatization with fluorescamine. Gun. Chem. 27, 1771 (1981). Letter. 2. Larsen, B., Grasso, D., and Chung, S., A rapid method of taurine quantitation using high performance liquid chromatography. J. Chromatogr. Sci. 18, 233-236 (1980). 3. Connolly, B. M., and G...

Article history: In this study, we established Received 11 October 2008 Accepted 25 October 2008 Available online 5 November 2008

The retention behaviour of four active compounds from Sophora Flavescens Ait using three ionic liquids as mobile phase modifiers was examined. The effect of the pH and the amount of ionic liquid modifier on the retention of these compounds was determined in methanol/water (v/v) as the mobile phase containing different ionic liquids ranging in concentration from 0.1 mmol/L to 3.0 mmol/L. The ion...