HPLC/UV/ELSD

OSM extracts were analysed by HPLC-UV/ELSD each compound present in the sample solution was identified by comparing its retention time with that of... 

Analysis of single-compound libraries by HPLC/UV/MS and, more recently, by HPLC/UV/ELSD/MS techniques, is generally accepted as the most appropriate means of characterization. The major steps of the analysis are the following ... 

J. N. Kyranos, H. Lee, W. K. Goetzinger and L. Y. Li, One-minute full-gradient HPLC/UV/ELSD/MS analysis to support high-throughput parallel synthesis, J. Comb Chem. 6 (2004), 796-804. 

Store the collection plate containing the dry sample or redissolve the sample in dimethylsulfoxide (DMSO) using the Quadra 96 for storage or for purity determination by HPLC/UV/ELSD. 

Purity of the samples extracted by the automated LLE or ion-exchange SPE can be determined by HPLC/UV/ELSD. The UV wavelength in a UV or PDA detector is typically set at 210 nm to observe both strong and weak UV-absorbing components. The ELSD detector is used to monitor non-volatile components that do not contain strong UV-chromophores. 

To avoid bottlenecks in the analysis, each step should be automated. Automation of data acquisition is achieved by automated HPLC/UV/MS/ ELSD instruments, equipped with autosamplers that allow compounds to be batch analyzed in unattended fashion. Recently, fast generic HPLC methods have been implemented for analysis of combinatorial libraries [33 53]. 

As these detection methods are complementary rather than mutually exclusive, multiple detection is recommended for laboratories that routinely perform the synthesis of discrete libraries and can be realized by splitting the eluate of the HPLC/UV system in two or three aliquots that are sent to the mass spectrometer and the CLND and/or the ELSD instrument. Examples of multiple UV/MS/CLND (67) and UV/MS/ELSD (68) show how the different methods of detection are useful in... 

The validation of materials upon entering the compound repository is assured by various analytical and separation techniques. Mass spectrometry is often featured for this application. A recent example of this by Pharmacia researchers [98] details an integrated HPLC system with detectors, including UV, ELSD, and CLND in addition to TOF-MS. More references on the use of hyphenated methods for library-quality assessment can be found in [91]—[97] in an earlier section, where library characterization is described. 

Figure 7.1.4 Analysis of shower gel containing C12-C14 ethoxylated alcohols by CE (A), HPLC-UV (B). (numbers above peaks indicate the degree of ethoxylation). Separation of fatty alcohol ethoxylates and of Cg-Cio polyglucosides by HPLC-ELSD (C). Adapted from Heinig et al (1998) with permission.

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