Principle of Sample Preparation for PCP

The sample preparation was carried out in accordance with the scheme in Fig. 9-6 [4]. 

This sample preparation method (Method 1) is the result of several experiments. An attempt was also made to extract the deproteinated sample with alkali (Method 2) without previously extracting with toluene. As a comparison, an experiment was carried out in which the toluene phase was evaporated to dryness and then acetylated (Method 3). The results are given in Table 9-5. The criterion was again the recovery rate. 

The differences in the recovery rates are due firstly to the polarity of PCP and secondly to its volatility. It is therefore important to cover the phase with isooctane 

Each point on the graph corresponds to 5 individual measurements 

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