High pressure liquid chromatography HPLC --continued

Since ISEs can be used in continuous flow systems or in flow systems with sample injection (flow injection analysis, FIA)21 their application is wide, not limited to discrete samples. Analysis time becomes shorter, with faster recycling. Additionally, in flow systems the experimental assembly and data analysis can be controlled automatically by microcomputer, including periodic calibration. Another development is the use of sensors for the detection of eluents of chromatographic columns in high-pressure liquid chromatography (HPLC). Miniaturization has permitted an increase in the use of sensors in foods, biological tissues, and clinical analyses in general. 

For some experiments the gas exiting from the photoreactor was continuously bubbled in hquid acetomtrile. The resulting solution was analyzed by high pressure liquid chromatography (HPLC) (Varian 9050) in order to detect... 

Reusability of the Electrode. Reusability of the microbial electrode was examined with the sample solution containing 125 r /mi of phenyl acetyl-7ADCA. The results obtained are shown in Figure 6. The cephalosporin determination was performed several times a day. However, no decrease of the potential difference was observed for a week. This system was applied to the determination of cephalosporins in a fermentation broth. Cephalosporin C in the cephalospolium acremonium broth was determined by the conventional method using high pressure liquid chromatography (HPLC) (13) and the electrochemical method. The results obtained are shown in Table 1. The relative error of the determination by the microbial electrode was within 10 %. Therefore, this system can be used for the continuous determination of cephalosporin in a fermentation broth. 

Nitrobenzene oxidation was carried out by adding 50 mg of dry soda lignin into a mixture of 7 mL of 2 M NaOH and 4 ttiL of nitrobenzene in a 15 ttiL steel autoclave. Then, the antoclave was heated to 165°C for 3 hours in a preheated thermostat oil bath. After the autoclave was cooled to room temperature, the mixture was then transferred to a liqnid-hquid extractor for continuous extraction with chloroform (5 x 20 mL) in order to remove any nitrobenzene reduction product and excess nitrobenzene. The oxidation mixtnre was then acidified by concentrated HCl to pH 3 and further extracted with chloroform (5x15 mL). The solvent from the second chloroform solution was then removed using a rotary evaporator at 40°C under reduced pressure in order to obtain the nitrobenzene oxidation mixture. The mixture was then dissolved into dicloromethane and made up to 10 luL. This mixture was then used as a stock solution for high performance liquid chromatography (HPLC) analysis [6]. 

The fact that the ionization occurs at atmospheric pressure in a continuous fashion, coupled with the high sensitivity of the technique, enables interfacing the mass spectrometer to column-based purification systems such as high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE).10,11... 

Packed bed, process scale high performance liquid chromatography (HPLC) equipment was first introduced by Millipore and Elf Aquitaine in 1982 [105] Since then, several companies, listed in Table 20, have entered the large scale HPLC market. The systems use packed beds at moderate pressures (30-140 bar). While there are substantial time-savings in using these systems compared to other purification techniques, the short life of the packing material and its high cost continue to restrict this technique to applications that warrant the 100/kg separation cost. 

HPLC. High-performance column liquid chromatography, performed under high pressure with narrow-bore columns containing small-diameter packings and continuous-flow detectors. 

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