Separation and identification of antidepressants by acrylate-based monolithic column capillary electrochromatography with UV detection.

This paper details a method for separation and identification of six antidepressant compounds using an acrylate-based porous monolithic capillary. Detection takes place using CEC coupled with UV or mass spectrometric detection. The CEC-UV method provides an effective and efficient method for the separation and identification of the analytes. Spiked urine samples were utilized to check method capability, and a liquid-liquid extraction procedure was developed to perform sample extraction. Detection limits ranged from 10 to 30 ng/mL.

Chiral separation of 12 cathinone analogs by cyclodextrin-assisted capillary electrophoresis with UV and mass spectrometry detection.

In this study, a rapid chiral separation of 12 cathinones analogs has been developed and validated using cyclodextrin-assisted CE with UV and TOF-MS detection. Optimum separation was obtained on a 57.5 cm × 50 µm capillary using a buffer system consisting of 10 mM ß-cyclodextrin (ß-CD) in a 100 mM phosphate buffer for CE-UV, and 0.6% v/v highly sulfated-γ-cyclodextrin (HS-γ-CD) in a 50 mM phosphate buffer for CE-MS. In the CE-MS experiment, a partial filling technique was employed to ensure that a minimum amount of cyclodextrin entered the mass spectrometer. All analytes were separated within 18 min in the CE-UV separation and identified by TOF-MS. Ten compounds were enantiomerically separated using ß-CD in the UV mode and an additional two more were enantiomerically separated using HS-γ-CD in the MS mode. Detection limits down to 1.0 ng/mL were obtained. The method was then applied to examine seized drugs.

Effects of electron beam irradiation on proteins and exopolysaccharide production and changes in Microcystis aeruginosa.

Purpose:Microcystis aeruginosa often threaten human health and safety for the toxin and unpleasant odor and removal difficulties during water treatment process. In order to remove it, a novel method high energy was studied in this research.Materials and methods: The electron beam generated by an accelerator was applied to irradiate M. aeruginosa at various doses of 1, 2, 3, 4 and 5 kGy. The effects of irradiation on M. aeruginosa characteristics and mechanism have been researched through surveying the changes in pH and conductivity, changes of algae cell community structure and respiration rate, and changes of protein and exopolysaccharides production were also detected.Result: The data showed that exposure to 2-5 kGy radiation could make pH decrease. Microcystis aeruginosa increased through its own photosynthesis and physiological regulation. The increasing damage to algal cells led to the exosmosis of the contents, which increased the electrical conductivity of algae liquid and decreased the area of algae cells colony. 2-5 kGy irradiation decreased protein content and destroy the antioxidant system and thus reduced the secretion of extracellular polysaccharidesConclusions: 2-5 kGy radiation could control the algae growth and produced obvious effect. The respiration rate decreased obviously that made M. aeruginosa lose activity in a short time. The results proved that irradiation could change the algae growth and affect its life characteristic efficiently in a short time.

A rapid method for separation and identification of microcystins using capillary electrophoresis and time-of-flight mass spectrometry.

This paper demonstrates a method for the rapid separation and identification of four microcystin (MC) variants commonly found in aquatic environments. The procedure utilizes capillary electrophoresis (CE) coupled to UV absorbance and time-of-flight mass spectrometric (TOF-MS) detectors. All four analytes were effectively separated within 6min using phosphate buffer in 50-µm ID capillaries with an applied electric field of 400V/cm. The separation of the individual compounds was optimized through the adjustment of buffer, pH, and ß-cyclodextrin content. Ultimately it was determined that, at a sufficiently high pH, all 4 compounds could be separated without the need for added cyclodextrins. The results provided accurate molecular information, assisting in the determination of compound identity. The method was then applied to environmental samples using solid phase extraction for isolation and pre-concentration. The results were comparable to those obtained by LC/MS, but with a shorter run time and lower sample and eluent consumption.

A novel fluorogenic coumarin substrate for monitoring acid phosphatase activity at low pH environment.

This article described the synthesis and application of 6-chloro-8-fluoro-4-methylumbelliferone phosphate (CF-MUP) in analyzing acid phosphatase activity. Compared to the existing MUP, the new coumarin phosphate, CF-MUP, demonstrateed much higher sensitivity and was more robust for detecting the activity of acid phosphatase than the classic substrate 4-methylumbelliferone phosphate (MUP). The product of enzyme reaction, 6-chloro-8-fluoro-4-methylumbelliferone (CF-MU) possesses strong fluorescence at approximately 450 nm with low pKa (4.7), high fluorescence quantum yield and pH independence in the physiological pH range. This new fluorescence dye, CF-MU, is a convenient tool for assays with buffer pH between 4.5 and 8.