(1028-A) Analysis of scopolamine and butylscopolamine in different matrices using microchip electrophoresis with integrated contactless conductivity detection

Abstract: The number of cases of robberies and sexual assaults facilitated by drugs has increased significantly in recent decades, with reports in the literature using scopolamine (SCO) for this purpose. Linked to this, there is a concern about obtaining scopolamine through the degradation by heating of butylscopolamine (BSCO) – an active ingredient in Buscopan® – a drug sold without a medical prescription. Various analytical techniques have been employed to determine BSCO and SCO in various types of matrices; among these techniques, the use of microchip electrophoresis (ME) devices coupled with contactless conductivity detection (C⁴D) is advantageous due to its miniaturization, portability, and cost-effective analysis. In this study, a mixture containing SCO and BSCO was separated and identified using a running buffer composed of 40 mmol L⁻¹ of butyric acid and 25 mmol L⁻¹ of sodium hydroxide (pH 5.0). The separation was performed within approximately 115 s with a resolution of 1.3 and separation efficiencies of 1.4 x10⁵ and 1.5x10⁵ theoretical plates m⁻¹ for SCO and BSCO, respectively. The achieved detection limit values were 1.1 μmol L⁻¹ for both species. Additionally, recovery tests were conducted at three different concentration levels, yielding values ranging from 102% to 104%. The developed methodology revealed satisfactory repeatability, with relative standard deviation (RSD) values for forty-eight injections between 4.8% and 9.4% for peak areas and less than 3.3% for migration times. Furthermore, inter-day precision was evaluated for sixteen injections (a sequence of four injections performed over four days), and RSD values were less than 6.6% for peak areas and 2.2% for migration times. Six drinks were chosen (cachaça, vodka, whiskey, beer, Coke, and grape juice) to evaluate the matrix effect. In all analyzed beverages, it was possible to detect and separate SCO and BSCO, achieving recoveries ranging from 95% to 114%. In artificial urine samples, the recovery values ranged from 95% to 107%. Both in beverage and urine samples, doping was simulated at concentration levels of 50 µmol L⁻¹ and 100 µmol L⁻¹. The Buscopan® dosage test was also conducted, yielding a result of 10.3 mg of BSCO, which closely matches the theoretical value of 10 mg of BSCO. Finally, through the heating of Buscopan®, it was possible to observe the conversion of BSCO into SCO, confirmed through analysis in capillary electrophoresis coupled to mass spectrometry (CE-MS). Based on the reported results, the use of ME-C⁴D devices has demonstrated significant potential for applications in the forensic chemistry field. It's worth noting that this study represents the first instance in the literature of separating and detecting scopolamine and butylscopolamine in beverages, urine, and pharmaceutical formulations using ME-C⁴D.