A major problem in the measurement of serum bile acids is their quantitative extraction from the high molecular protein matrix. In our hands, the standard techniques of adsorption and reversed-phase chromatography have yielded incomplete recovery for different bile acids (33-93%) and poor reproducibility. In contrast, with the novel extraction procedure of size exclusion chromatography, recover...

Purification of peptides is often the most difficult part of the process used to obtain the compounds [1]. Several methods are used for isolation and subsequent purification of the post-synthesis mixture. Depending on the properties of the peptide and the types of impurity, commonly used techniques are ion-exchange chromatography and gel filtration [2,3]. The standard method for isolation is hi...

An improved method for trace level quantification of dicyandiamide in stream water has been developed. This method includes sample pretreatment using solid phase extraction. The extraction procedure (including loading, washing, and eluting) used a flow rate of 1.0mL/min, and dicyandiamide was eluted with 20mL of a methanol/acetonitrile mixture (V/V=2:3), followed by pre-concentration using nitr...

background and objectives: the addition of plasticizers (mainly phthalates and adipates) makes plastic flexible and popular for packaging, storing and preserving food, water, and so on. the most widely used plasticizer in food contact applications is di-ethylhexyl phthalate (dehp) though being suspected to have carcinogenic and estrogenic properties. the aim of this study is application of magn...

The development of automatized hyphenated systems is attractive to avoid sampling error, save time and reduce costs. Among these systems, on-line SFE-SFC allows the extraction, separation, detection molecules in an efficient, quick eco-friendly way. After a historical introduction explanation on use supercritical fluids for extraction or analysis, principles fluid (SFE) chromatography (SFC) wil...

styrene is an important constituent of widely used organic solvents in industries for production of various synthetic materials. the use of solid-phase extraction (spe) has grown and is a fertile technique of sample preparation as it provides better results than those produced by liquidliquid extraction. in this study, spe has been optimized, regarding sample ph, sample concentration, sample fl...

We describe the first realization of liquid chromatographic separation in a droplet-based microfluidic system and develop a novel mode for microchip-based chromatography named as droplet-array liquid-liquid chromatography. In this system, two arrays of picoliter-scale droplets immobilized on both sidewalls of a microchannel with droplet trapping technique served as the stationary phase in chrom...

Methods were developed for the extraction and separation of soil organic phosphorus compounds using reverse-phase ion-pair chromatography (RP-ICP). Nucleotides (ATP, ADP, and AMP) were separated using a mobile phase of 15 mM TBAHS, 15 mM KH2PO4, and 7% acetonitrile. Inositol hexakisphosphate was separated using a mobile phase composition of 0.05 M formic acid:methanol (49:51 v/v) and 1.5 mL/100...

In this paper high-performance liquid chromatography with diode array UV detection (HPLC/DAD) after SPE sample pretreatment for simultaneous analysis of pharmaceuticals from three different classes: enrofloxacin, oxytetracycline and trimethoprim, has been developed, optimised and validated. The chromatographic separation was developed on spiked wellspring water samples and checked on model wast...

A rapid method for the extraction, separation and quantification of the 4-hexylresorcinol from shrimp with high performance liquid chromatography (HPLC) is described. This modified method is faster than previously described methods with short pre–preparation and sharp resolution in HPLC procedures (sample preparation, extraction, separation and quantification total 40 min.). The coefficients of...