Chromatographic screening, automate

Method development remains the most challenging aspect of chiral chromatographic analysis, and the need for rapid method development is particularly acute in the pharmaceutical industry. To complicate matters, even structurally similar compounds may not be resolved under the same chromatographic conditions, or even on the same CSP. Rapid column equilibration in SFC speeds the column screening process, and automated systems accommodating multiple CSPs and modifiers now permit unattended method optimization in SFC [36]. Because more compounds are likely to be resolved with a single set of parameters in SFC than in LC, the analyst stands a greater chance of success on the first try in SFC [37]. The increased resolution obtained in SFC may also reduce the number of columns that must be evaluated to achieve the desired separation. 

The greatest advantage of the spectrophotometric method is that it is direct and rapid, requires no sample workup, and allows for continuous assays of lipase activity compared to the multiple fixed-time-point analyses incumbent within Basic Protocols 1 and 2. The spectrophotometric method can also be done using very small volumes (as small as 1 ml) and is suitable for following the course of purification (such as in chromatographic fractions) or adaptable to 96-well plates (and subject to automation, if available). Thus, it is the method of choice for screening several samples or preparations for lipase (esterase) activity. 

Sadeg N, Francois G, Petit B, Dutertre-CateUa H, Dumontet M. Automated liquid-chromatographic analyzer used for toxicology screening in a general hospital 12 months experience. Clin Chem 1997 43 498-504. 

Yuen et a1. (62) developed an automated system that permits DTA, TG, DTG, and mass specirometry (MS) measurements to be performed simultaneously on a single sample in inert or oxidative atmospheres. A Hewlett-Packard 5992 quadrupole mass spectrometer was used to obtain the MS data. Software programs were developed for (1) continuous MS monitoring of volatiles, (2) screening of the acquired MS data, (3) tabulation of mass spectra, (4) subtraction of mass spectra acquired at two different times, and (5) TA curves and mass ion profiles. This system was modified by the addition of a gas chromatograph so that it had GC/MS capability (62) as well as the aforementioned TA techniques. 

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