Scott test paper: A solvent-free, portable presumptive method for cocaine detection in field forensic applications

Presumptive colorimetric tests are widely used in forensic field investigations. However, the conventional liquid Scott test has important operational drawbacks for patrol officers, including limited portability, higher costs, user exposure to hazardous chemicals, and the generation of chemical waste. In this context, this study aimed to develop a Scott test paper (STP) by immobilizing a cobalt thiocyanate reagent in glycerin onto a paper matrix. Evaluation with authentic street cocaine samples showed a limit of detection (LOD) of 4 mg·mL⁻¹ and 100% agreement with the conventional Scott test. Overall, the STP proved to be a safe and effective tool for the qualitative detection of cocaine in seized samples, both in solid form and in solution. It is contamination-free and compatible with standard police field equipment. Importantly, the STP overcomes key limitations of the conventional method by improving portability, reducing operator exposure to hazardous reagents, and minimizing chemical waste generation. As with the conventional Scott test, the STP retains known selectivity limitations and positive results require confirmatory laboratory analysis.