Array detectors formats

The dehydrogenation reaction was generally monitored by taking samples for reversed phase H PLC analysis. Diode array detectors for H PLC were relatively new at that time and proved valuable for quickly getting structural information on products of the reaction produced under different conditions. Key reaction parameters for adduct formation, overall concentration, BSTFA, TfOH, and DDQ charges, were optimized using a thermostated HPLC autosampler to sample reactions directly for analysis. Comparison of reaction profiles provided rate and reaction time information that was used to select a more limited number of reaction conditions that were scaled up to compare yields. 

Imaging with large format array detectors... 

Large format array detectors consist of numerous, small detection elements arranged in a two-dimensional grid. Array detectors are akin to the ubiquitous modern digital camera in that they are passive recording devices that simply record the incident intensity of the entire FOV at a specified time. Hence, they can be incorporated... 

The commercial softwares, initially developed by instrament manufacturers for open-access operation, were adapted to enable unattended data acquisition and automated data processing for large series of samples from an autosampler supporting the 96-well microtitre plate format, which is the sample format of choice in combinatorial synthesis. Initially, mainly Gilson 215 or 233 XL autosamplers were used, but other systems have become available from other instrument manufacturers. The complete system is under control of the MS data system. It consists of a 96-well-plate autosampler, an LC pumping system, eventually a UV-photodiode-array detector (DAD) in series and/or evaporative hght scattering (ELSD) detector in parallel, and the mass spectrometer eqnipped with ESI, APCI, and/or atmospheric-pressure photoionization (APPI). 

Rapid quantification of products and substrates in a fermentation process is essential for process development and optimization. Most fermentation laboratories have access to HPLC equipment with possibilities to couple them to quite inexpensive diode-array-detectors, and this equipment could be used for quantitative monitoring of the process. Because HPLC can allow multi-component analyses, i.e., several analytes in the same sample can be determined virtually simultaneously, and since it is often necessary to monitor more than one substance at a time, this technique is an important tool for bioprocess monitoring. HPLC coupled to expensive MS does not represent standard equipment at fermentation laboratories. Even if mass spectrometers are available, DAD is often sufficient for quantification because product concentrations are relatively high, so the MS could be used for other issues. In paper II the goal was to develop and validate a method for analytical quantification of both the product and the substrate to enable the proper characterization of the kinetics of the process i.e., the determination of the values of substrate conversion and product formation. 

Substrate depletion and product formation were also followed by HPLC with an HP1090 Series II hquid chromatograph with a diode-array detector. A 10% methanol-water mixture was used as eluent. 

Tacrine and seven metabolites (e.g., 2-hydroxy-, 4-hydroxy-, and 1-hydroxy-tacrine) wbre resolved on a phenyl colunm (photodiode array detector, X = 230-360 ran or UV at 2 = 325 ran) using a 70/30 acetonitrile/Avater (ammonium formate pH 3.1) mobile phase [1549]. The analysis required 25 min. Preparative LC was conducted with identical mobile phase conditions and a preparative-scale phenyl column. 

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