The choice of analogue ion of the mobile phase additive is shown to significantly affect the analysis of quaternary ammonium compounds (QACs) in ion-pair reversed-phase high-performance liquid chromatography. A series of bromide-containing and dodecyl-sulfate-containing mobile phase additives are investigated using two QAC probe analytes. In all instances, the quaternary-ammonium-containing mob...

the air quality in shiraz was assessed based on a one-week passive sampling campaign.during the first week of the summer 2003, about 400 passive samplers were used in groups of two andthree, so that 187 sampling stations covered all of shiraz. pollutant gases including so2, no2 and btx(benzene, toluene and xylene) were sampled by diffusive sampling tubes. collected samples wereanalyzed and poll...

phosalone, malathion and diazinon were analyzed in corn oil using solid phase extraction (spe)with lanthanum silicate as a new solid sorbent followed by gas chromatography with nitrogenphosphorus detection (gc-npd). the efficiency of different eluents (methanol, dichloromethane,ethyl acetate, dichloromethane — ethyl acetate (1:1) and ethyl acetate — methanol (1:1)) werecompared for elution of o...

In the different compartments of the environmental chromium occurs mainly in the oxidation states (III) and (VI). Although Cr(III) is an essential trace element for humans, Cr(VI) is highly cancerogenic and mutagenic. It is, therefore, necessary for risk assessment not only to determine total chromium, but also to determine chromium species, especially Cr(VI). Hexavalent chromium can be determi...

A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method is presented for the qualitative screening for 238 drugs in blood samples, which is considerably more than in previous methods. After a two-step liquid-liquid extraction and C(18) chromatography, the compounds were introduced into a triple quadrupole mass spectrometer equipped with a turbo ion spray ion source operating in the p...

This review focuses on the ion chromatographic methods for the analyses of natural waters with high ionic strength. At the beginning a natural diversity in ionic composition of waters is highlighted and terminology clarified. In continuation a brief overview of other review articles of potential interest is given. A review of ion chromatographic methods is organized in four sections. The first ...

We evaluated the use of ion-exclusion chromatographic systems for analyzing the behavior of inorganic ions (e.g., bicarbonate, sulfate, chloride, nitrate, phosphate, dissolved silicate, sodium, ammonium, potassium, magnesium, and calcium ions) in a suburban river located in Jakarta, Indonesia. Carbonate, phosphate, and silicate ion concentrations were determined using ion-exclusion chromatograp...

BACKGROUND In clinical and forensic toxicology, general unknown screening is used to detect and identify exogenous compounds. In this study, we aimed to develop a comprehensive general unknown screening method based on liquid chromatography coupled with a hybrid triple-quadrupole linear ion trap mass spectrometer. METHODS After solid-phase extraction, separation was performed using gradient r...