High-performance liquid chromatography detectors used

Bispyribac in water samples can be directly quantifled by high-performance liquid chromatography (HPLC) using an ultravilot (UV) detector without methylation. 

High performance liquid chromatography is used to determine the purity of calcitriol, and to separate it from related compounds. Using a 10 micron silica column of 25 cm length, and a mobile phase of spectroquality heptane ethyl acetate. methanol (50 50 1) at a flow rate of 1.7 ml/ minute, separation and quantitation are achieved. p-Dimethyl-aminobenzaldehyde may be used as an internal standard to compensate for variations in injection technique and instrumental conditions. With a 254 nm ultraviolet absorbance detector, 0.01 ug of calcitriol may be detected (3). 

While lactose may be determined by gas liquid chromatography, high performance liquid chromatography (HPLC), using a refractive index detector, is now usually used. 

Duan et al. reported the use of a rapid and simple method for the determination of acetylcholine and choline in mouse brain by high performance liquid chromatography, making use of an enzyme-loaded post column and an electrochemical detector [144]. Perchloric acid extracts of small brain tissue were injected onto the HPLC system with no prior clean-up procedure. Detection limits for both compounds were 1 pmol, and this method was successfully applied to the measurement of acetylcholine in discrete brain areas of the mouse. 

Westwood, S.A. Games, D.E. Sheen, L. Use of circular dichroism as a high-performance liquid chromatography detector. Chromatography 1981, 204, 103-107. 

Ultramicroelectrode Synonymous with microelectrode. Ultraviolet/visible detector, HPLC Detector for high-performance liquid chromatography that uses ultraviolet/visible absorption to monitor eluted species as they exit a chromatographic column. 

Cmde dextransucrase was reacted with 100 mM sucrose for 1 h at 30 °C and then boiled for 5 min to terminate the enzyme reaction. One unit of dextransucrase activity was defined as that amount of enzyme releasing 1 p.M fructose per min from 100 mM sucrose. The fructose was determined by high-performance liquid chromatography (HPLC) using an Aminex FIPX 87K column (300 7.8 mm) and an HPLC analyzer coupled to a refiactive index detector. The column was maintained at 85 °C and 0.01 M K2SO4 was used as a mobile phase at a flow rate 0.6 ml/min. 

The concept that molecular weight and polarity play a role in determining the composition of an asphaltene fraction is very realistic but does not present any indication of the nature of the polynuclear aromatic systems in the asphaltene fraction of petroleum. Thus, the purpose of this chapter is to present new data that provide indications of the ring-size distribution in petroleum asphaltenes. The evidence is accumulated by asphaltene fractionation and subsequent examination of the fractions by high-performance liquid chromatography (HPLC) using a UV detector. 

The second method uses preconcentration to increase the analyte concentration in the absorption solution to detectable levels prior to analysis. One example is the use of solid-phase extraction with an anion exchange column as a pretreatment technique to remove interference from the sample matrix and to enhance the detection sensitivity prior to determination of the concentrated iodide anion through reversed phase high-performance liquid chromatography (HPLC) using an ultraviolet (UV) detector. The results show more than 90% recovery and good reproducibility for the determination of trace iodine in iodine-enriched eggs. 

High Performance Liquid Chromatography. All separations were performed using an Altex Scientific (1780 Fourth Street, Berkeley, CA 94710) Model 320 Advance Research Chromatograph, consisting of a model lOOA dual piston analytical pump, a Model 153 UV detector, a Model 210 injection valve, and a Model 155 recorder. The columns (600 x7.5mm) evaluated were the Spherogel TSK-SW-2000 and SW-3000 (Altex). Unless otherwise stated, all separations were carried out at 23 - 25 . 

High-performance liquid chromatography (HPLC) with a micellar mobile phase or with a selective pre-column or reaction detection system has also been used to determine alkylenebis(dithiocarbamaes). ° Zineb and mancozeb residues in feed were determined by ion-pair HPLC with ultraviolet (UV) detection at 272 nm. These compounds were converted to water-soluble sodium salts with ethylenediaminetetra-acetic acid (EDTA) and sodium hydroxide. The extracts were ion-pair methylated with tetrabuthylammonium hydrogensulfate (ion-pair reagent) in a chloroform-hexane solvent mixture at pH 6.5-8.S. The use of an electrochemical detector has also been reported. ... 

---