Detectors Method development detection

Parameters that should be tested in HPLC method development are flow rate, column temperature, batch and supplier of the column, injection volume, mobile phase composition and buffer pH, and detection wavelength [2], For GC/GLC methods, one should investigate the effects of column temperature, mobile phase flow rate, and column lots or suppliers [38], For capillary electrophoresis, changes in temperature, buffer pH, ionic strength, buffer concentrations, detector wavelength, rinse times, and capillaries lots and supplier should be studied [35, 36], Typical variation such as extraction time, and stability of the analytical solution should be also evaluated [37],... 

With the development of sophisticated ionization techniques including electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI), HPLC-MS techniques have been successfully applied to the online analysis of ginsenosides in extracts and biological fluids (Fuzzati, 2004). In terms of sensitivity and specificity, an MS detector is better than UV or ELSD. Among the various MS methods, the HPLC-MS-MS (or just LC-MS-MS) technique is to date the most sensitive method for detection and quantification of ginsenosides. 

A diode array detector is well suited to achieve these goals. Full range spectra should be collected for the method development samples and evaluated with two-dimensional or three-dimensional visualization to determine the best detection wavelength. 

Analytical Method Development for TRIS. The detection of brominated compounds of very low volatility such as TRIS posed special analytical problems. Since TRIS has no recognizable chromophore, the detection systems which are commonly used with high performance liquid chromatography (hplc), such as refractive index or short wavelength (<220 nm) uv detectors, are too non-specific to be of much practical use for the analysis of environmental samples. Furthermore, the sensitivities available with these detection methods are generally inadequate. 

The chapter is divided into 10 parts devoted to individual groups of antimicrobial agents. The text is focused mainly on sample pretreatment, new achievements in method development, comparison with other techniques, and the factors limiting chromatographic analysis. The sample pretreatment and detection conditions (especially for MS detectors) are presented only in the main features, to make the text more concise. 

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