RESUMEN
Falsified medicines and healthcare supplements provide a major risk to public health and thus early identification is critical. Although a host of analytical approaches have been used to date, they are limited, as they require extensive sample preparation, are semi-quantitative and/or are inaccessible to low- and middle-income countries. Therefore, for the first time, we report a simple total analysis system which can rapidly and accurately detect falsified medicines and healthcare supplements. We fabricated a poly-lactic acid (PLA) pestle and mortar and using a commercial 3D printer, then made carbon black/PLA (CB/PLA) electrodes in the base of the mortar using a 3D printing pen to make an electrochemical cell. The pestle and mortar were able to crush and grind the tablets into a fine powder to the same consistency as a standard laboratory pestle and mortar. Using melatonin tablets to characterise the device, the 3D-printed pestle and mortar was able to detect the concentration of melatonin in the presence of insoluble excipients. The calibration plot showed a linear response from 37.5 to 300 µg/mL, where the limit of detection was 7 µg/mL. Electrochemical treatment was able to regenerate the CB/PLA working electrode allowing for repeated use of the device. In a blinded study, the device was able to accurately determine falsified melatonin tablets with recovery percentages between 101% and 105%. This was comparable to HPLC measurements. Overall, these findings highlight that our 3D-printed electrochemical pestle and mortar is an accessible and effective total analysis system that can have the ability to identify falsified medicines and healthcare supplements in remote locations.