Lindane sample preparation

In the quantitative determination of lindane and PCP from the matrix blood, the sample preparation process is an essential step for ensuring that the results will be of good quality. In this process, interfering substances contained in the matrix are removed, and the substances to be determined are converted into a chemical form that enables them to be measured by GCZMS. 

PCP and lindane are chemically different, and appropriate methods of sample preparation must be used. Lindane can be measured by GC without derivatization, but PCP contains a polar functional group and must first be converted into a form in which it readily vaporizes in the injector. For this, a derivatization step is necessary. 

Conventional liquid-liquid extraction for the determination of lindane has been used very frequently up to the present time. However, this classical method of sample preparation has disadvantages, e.g. emulsion formation, poor phase separation, high consumption of solvent, and the labor-intensive nature of the process and its unsuitability for automation. It was important to find ways of... 

Figure 9-3 shows the calibration line of lindane. This line was used to determine the recovery rates. For this, the peak area of a standard was determined. The standard was then added in known concentration to a sample of pooled blood and the sample preparation method described above was applied. The recovery rate can be found from the peak area of the standard and that of the blood with the added standard. Each calibration point shown in Fig. 9-3 represents the mean of five individual measurements from the matrix blood. 

Figure 9-4 shows full-scan and SIM spectra of 1 pg lindane added to blood and subjected to sample preparation using the method described above. 

This high and reproducible percent recovery for the isolation and recovery of lindane from water strongly suggests that RP-SPE is very appropriate as a sample preparation method for this analyte. Lindane is of continued interest to environmental and toxicological scientists. One such study, discussed next, taken from the author s work, involves the isolation and recovery of lindane from homogenized myometrial tissue suspended in an aqueous matrix. 

In addition to a tabular format for the determination of lindane in each of the myometrial tissue samples submitted, a method summary should be included. A one paragraph method summary serves to inform the reader as to how the samples were handled once they arrive in the analyst s laboratory. The summary should also provide a brief overview of the sample preparation and a brief description of the determinative technique used. The following report illustrates these concepts. 

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