I believe that there are

I believe that there are Pacritinib FLT3 other reasons as well for the persistence and prevalence of UV/DAD. Firstly the use of derivative UV/Vis spectroscopy facilitates the determination of one or more wavelengths where the compound of interest absorbs. Thus, the compound can be analyzed with negligible absorption from excipients/matrix. In one of the articles in this journal, I see the use of isobestic point in a bi-component sample analysis. Also, the widespread replacement of conventional (and very limited) UV/Vis detectors with DAD allows for simultaneous multi-component analysis, once certified or reference standards are available. DAD detectors are equipped with the software to perform peak purity assessment, thus providing an extra level of quality control to the LC�CUV/DAD analysis.

Unknown components in a sample are unlikely to be a problem in the pharmaceutical industry as they may be in, for example, the field of natural products chemistry. Even in the event that a drug preparation contains an alien component, there are many consultancy laboratories that will provide analyte identification quickly and economically, thus negating the need for an organization to invest in very elaborate and costly technologies. LC�CUV/DAD does, however, require that three conditions are met: The molecule must possess a chromophore or be tagged with a UV absorbing group. There has to be reasonable resolution between the target analyte and co-eluting impurities. The target compound and co-elutant must absorb at different wavelengths.

Once these criteria are fulfilled, the LC�CUV/DAD technology is more than capable of fulfilling the requirement of the regulatory authorities. There is also, I think personally, a growing awareness that MS technology is not the panacea that it once seemed; for example, it is prone to ion suppression/enhancement effects which can compromise its quantitative ability. Many published papers fail to investigate whether or not their method is susceptible to this phenomenon. Ion suppression results in the presence of low volatile interferences (salts, ion pairing agents, and drug components amongst others have been identified as culprits) in the sample matrix that hinders droplet formation and evaporation at the ionization interface. This then affects the amount of charged ion in the gas that reaches the detector.

In fact, ion suppression may not be evident during method development and emerges Anacetrapib only in the sample analysis stage. There are also many published papers which emphasize that LC�CMS requires little or no sample clean up. There are papers that have even gone so far as to say that chromatographic resolution of co-elutants is unnecessary. This may be the case for qualitative analysis where, for example, multiple reaction monitoring (MRM) may be deployed but is a gravely insufficient and misleading strategy for method validation.

Leave a Reply

Your email address will not be published. Required fields are marked *


You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>