Chemiluminescent nitrogen detection CLND

Relative purity measurement and the relative purity-based reaction optimization have long been used in combinatorial synthesis. In order to make high-through-put purification a success, the yield-based optimization is essential. Chemiluminescent nitrogen detection (CLND) [4] with HPLC determines the quantitative yield after each reaction step during the library feasibility and rehearsal stages. The yield of each synthetic step provides guidance for the final library synthesis. 

Gradient RP-HPLC separation with 0.1% formic acid and methanol as mobile phase components (0.25 mL/min) combined either with ESI-time-of-flight [23] MS detection or with chemiluminescence nitrogen detection (CLND) was used to identify and, respectively, quantify illicit drugs in seized material without primary reference standards [24], The method exploits the accurate mass measurement provided by TOE MS, enabling the unequivocal identification of molecular formula of the unknown analyte, and the CNLD equimolar response to nitrogen. 

In LC/MS analysis of combinatorial libraries, the MS determines the product identity and its purity is determined by other on-line detection techniques such as UV, evaporative light scattering detection (ELSD), and chemiluminescent nitrogen detection (CLND).17-20 UV detection is used here to assess product purity based on the assumption of similar absorption coefficients at 214 nm for the desired product and the side-products. 

The physical quality of samples is assessed via analytical methods. Liquid chromatography with mass spectrometry (LC-MS) is the most common instrumentation used to determine sample presence and purity (Kerns et al., 2005). Chemiluminescent nitrogen detection (CLND), charged aerosol detection (CAD) and other techniques have also been used to determine concentration (Popa-Burke et al., 2004 Gamache et al., 2003). 

Since the UV response as a measure of purity and quantity determination is questionable due to the different extinction coefficients of individual components of a crude preparation, alternative detection systems were advocated, such as the evaporative light scattering detector (ELSD) and the chemiluminescent nitrogen detector (CLND). " In addition, NMR techniques were adopted that allowed structural confirmation, purity characterization, compound solubility, solution stability, and biological testing from a single DMSO stock solution. The quality control process for descriptions of chemical library members was discussed by Yan in 2004. ... 

SPTD short-path thermal desorption unit CLND chemiluminescent nitrogen detector CL peroxyoxalate chemiluminescence detection CELL continuous liquid-liquid extraction. 

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