Development of analytical method for illegal substances in sweat and comparison of the effectiveness of sweat collection materials

Abstract

Purpose: Sweat analysis can yield valuable information in forensic investigations, diagnosis and treatment. The purpose of this study was to develop a validated gas chromatography-mass spectrometric method for the detection of illegal substances in sweat after optimizing the method by chemometric approach. This study also investigated the effectiveness of alternative sweat-collecting materials.

Methods: Plackett-Burman screening design was employed to determine the effect of seven process factors on this new method. Then, central composite design (CCD) was used to optimize the method. The method was validated according to the international guidelines. The effectiveness of alternative sweat-collecting materials (cosmetic pads and swabs) was compared with a commercially available collecting device (DrugWipe5A).

Results: Sample pH, ultrasonic bath time, and liquid-liquid extraction (LLE) shaking time were determined as the most significantly effective three parameters with the Plackett- Burman screening design. The validation procedure was successfully performed after optimizing this method. The comparison study demonstrated that cosmetic pads, swabs, and DrugWipe5A can be used interchangeably.

Conclusions: Our results suggested that the statistical optimum strategy was an effective tool for the optimization of process parameters. Combined with the sensitivity and selectivity of our method, the analysis of sweat collection materials proved to be a useful tool for physicians and health care professionals.

Keywords: Chemometry; DrugWipe5A; Gas Chromatography–Mass Spectrometry; Illegal substance analysis; Sweat testing.