Semiqualitative analysis

The objective of an analytical measurement can be qualitative or quantitative. For example, the presence of pesticide in fish is a topic of concern. The questions may be Are there pesticides in fish If so, which ones An analysis designed to address these questions is a qualitative analysis, where the analyst screens for the presence of certain pesticides. The next obvious question is How much pesticide is there This type of analysis, quantitative analysis, not only addresses the presence of the pesticide, but also its concentration. The other important category is semiqualitative analysis. Here... 

The literature relating to the effects of storage and processing on the retention of tocopherols in foods is limited, controversial, and inadequate. Most of the published data must be considered to be qualitative, or at most semiqualitative, for the methods of analysis for total tocopherols have only recently become precise. Even so, accurate data on the total tocopherol content of a food or tissue are not pertinent because the several natural tocopherols they contain differ greatly in vitamin E activity. 

Although band separation is not as critical for CLS as it is with OLS, unremoved and/ or varying backgrounds can devastate a CLS prediction. Possibly the most difficult to meet requirement of CLS or OLS is that the calibration set must represent all the expected components in one or more samples. Any unexpected component will introduce a bias into the prediction of the components which were included in the calibration. Few articles have explicitly used CLS for analysis of Raman spectra. One example can be found in a semiqualitative study of neurotransmitters in which CLS is compared to neural networks [63]. 

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