Alternative Dynamic Calibration Procedures

It is not the purpose of this chapter to provide an exhaustive account of gas calibration techniques. However, we note that other techniques have been developed for calibrating 

PTR-MS systems, some of which are variants of the techniques already described above. These alternative methods aim for portability, a reasonable cost and applicability to many volatile compounds. 

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Two procedures for improving precision in calibration curve-based-analysis are described. A multiple curve procedure is used to compensate for poor mathematical models. A weighted least squares procedure is used to compensate for non-constant variance. Confidence band statistics are used to choose between alternative calibration strategies and to measure precision and dynamic range. 

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