High-performance liquid chromatographic analysis of dinitrobenzene isomers

Summary An efficient, reproducible and rapid high-performance liquid chromatographic method, in normal phase mode, for the analysis of the three dinitrobenzene isomers is described. The method affords good linearity for each isomer in the range 10–160 g ml^–1. The total analysis time is only 10 minutes, and the method shows an accuracy of ±1.25% with a coefficient of variation from 0.30% to 2.85% for different levels of the dinitrobenzene isomers.     

High-performance liquid chromatographic analysis of steroid hormones

In the present work, a practical, rapid, reliable and isocratic reversed-phase high-performance liquid chromatographic (HPLC) method is described for the qualitative and quantitative analysis of estriol, estradiol-17 beta, estrone, testosterone, and progesterone. Chromatographic separation is complete in 16 min using a mobile phase of 50% acetonitrile (v/v) in water. The order of elution is estriol, testosterone, estradiol-17 beta, estrone, and progesterone; retention times are 2.5, 5.5, 5.6, 6.9, 16.3 min, respectively. Absorbance maxima of individual steroids is the limiting factor in quantitative determination. The recommended wavelengths for UV monitoring are E3 214, E2 280, T 254, E1 214, and P4 254 nm.     

High-performance liquid chromatographic analysis of dehydroepiandrosterone.

Qualitative and quantitative analysis of dehydroepiandrosterone and its conjugates in biological matrices and establishment of their relationships with physiological functions is a very active field. This review article discusses methods of separation and quantification of dehydroepiandrosterone and its conjugates using high-performance liquid chromatographic techniques.     

High-performance liquid chromatographic fractionation and characterization of fulvic acid

High-performance immobilized metal ion affinity chromatography (HP-IMAC) was used to fractionate humic substances (HS) based on their affinity for the immobilized copper(II) ion using acidic and glycine eluents. The work was carried out with two naturally occurring aqueous fulvic acids and commercially available Suwannee River fulvic acid. The IMAC-fractionated HS were then characterized by reversed-phase high-performance liquid chromatography (RP-HPLC) and size exclusion chromatography. The results showed that the affinity HS fraction eluted first using an acidic pH=2 eluent exhibited a relatively high hydrophilic character, whereas the fraction eluted later using a glycine eluent exhibited both a higher hydrophobic character and larger molecular size. On the other hand, the HS fraction with no affinity for the immobilized copper had low molecular size. The affinity of the HS fraction for copper(II) increased with increasing molecular weight. Based on the composite results of three different HS, it is evident that strong relationships exist between affinity, molecular weight, and hydrophilic/hydrophobic properties during the HP-IMAC fractionation. The results presented here have significance for understanding the nature of chemical interactions at the molecular level between dissolved organic matter and trace metals. IMAC, coupled with other liquid chromatographic strategies, is a promising tool for chemical fractionation and characterization of HS.     

High-performance liquid chromatographic analysis of azlocillin in serum

Summary A rapid and sensitive high performance liquid chromatographic method is described for the determination of azlocillin in serum. This method involves a short manual protein precipitation of the sample followed by an injection into a PR 18 column for separation and quantitation. The mobile phase was a 22% (V/V) solution acetonitrile in phosphate buffer pH 4.8 at a flow rate of 2,5 ml/min. The spectrophotometer detector was set at 220 nm with a sensitivity of 0.08 AUFS.     

High-performance liquid chromatographic analysis of g;ycosaminoglycan-derived oligosaccharides

High-performance liquid chromatography of glycosaminoglycan (GAG)-derived oligosaccharides has been employed for structural analysis and measurement of hyaluronan, chondroitin sulphate, dermatan sulphate, keratan sulphate, herapan sulphate and heparin. Recent developments in the separation and detection of unsaturated dissacharides and oligosaccharides derived from GAGs by enzyme or chemical degradation are reviewed.