A sensitive liquid chromatograph/tandem mass spectrometric technique (LC/MS/MS) was applied to determine aliphatic and aromatic carbonyl compounds in ambient air. Traces of the carbonyl compounds were sampled by passing through a Sep-Pak DNPH-silica cartridge. Their derivatives were thus eluted with acetonitrile, separated by reversed-phase liquid chromatography and determined by quadrupole tan...

In this liquid-chromatographic method for determination of urinary oxalate, interfering compounds in the urinary samples were eliminated before chromatography by passage through a preparative C18 mini-column (Sep-pak cartridge, Waters Associates). In the reversed-phase system tetrabutyl ammonium was included as a counter ion to enhance the retention of oxalate. The pH of the mobile phase was ke...

We have used two methods for the preparation of a highly homogeneous insulin with high specific activity. After iodination with chloramine T, the labeled peptides were retained on a disposable Sep Pak cartridge and subsequently eluted. The eluted labeled insulins were further purified by either DEAE cellulose or high performance liquid chromatography (HPLC) to separate A14-125I- from A19-125I-i...

A simple method using HPLC and LC-MS/MS was developed for the determination of ultra-high-intensity sweetener, advantame, in processed foods. Advantame was extracted by dialysis, and cleaned up on a Sep-Pak Plus C18 cartridge, then determined by HPLC and LC-MS/MS. The recoveries from 5 kinds of processed foods fortified at the levels of 0.001 g/kg and 0.01 g/kg were 64.1-89.9% (RSD 0.9-6.9%) by...

For the determination of total mercury in hair, an amount (25.0 mg) of hair sample was digested with conc. HNO3 (400 microl) at 90 degrees C for 10 min in a 7-ml teflon microreaction vessel. After digestion, the pH of the acidic hair mixture was adjusted to 5.0-6.0 by NaOH and was then passed through a clean-up Sep-Pak C18 cartridge. To the eluate, 2,3-dimercaptopropane-1-sulfonate (DMPS) and s...

Peptides are naturally occurring biological molecules that found in all living organisms. These biologically active peptides play a key role various processes. The aim of this study is the extraction and purification bioactive materials induce relaxation an apical muscle from pyloric caeca Patiria pectinifera. acidified extract was partially separated by solid phase using stepwise gradient on S...

A reliable and rapid high-performance liquid chromatography (HPLC) method has been set up for the determination of total thiamin in difficult sample matrices such as cooked sausages. Different hydrolysis conditions and enzymes were tested to release the vitamin from its phosphate ester. The best data in the enzymatic digestion were obtained by incubating the samples with 6% clara-diastase at 50...

A comprehensive analytical method has been developed and validated for the simultaneous determination of seventeen glucocorticoid residues in eggs and milk. The mass spectrometer parameters, the composition of the mobile phase and the sample preparation method were firstly optimized to obtain maximum sensitivity. The samples were deconjugated with beta-glucuronidase/arylsulfatase enzyme and con...

Purpose: Zygophyllum fabago L. (Z. fabago) is a widespread perennial herb which is used as a medicinal plant in traditional medicine of Iran, Turkey and China. The present study was a survey on phytochemical constituents and biological activities of this plant. Methods: Methanolic extract of the roots was fractionated over a C-18 pre-packed cartridge (Sep-pak) and chromatographic separation was...