Colorimetric 3D microPAD for Multiplexed Detection of Paracetamol and Aspirin in Urine and Saliva

In this work, a novel 3D μPAD cellulose-based colorimetric chemosensor for multiplexed detection of paracetamol and aspirin in biological samples is proposed. The easy availability of analgesics such as paracetamol and non-steroidal anti-inflammatory drugs such as aspirin, over-the-counter drugs that can be acquired without medical prescription, can entail a health problem if they are administered incorrectly. The development of analytical procedures for the rapid, sensitive, and accurate determination of such drugs in clinical samples is of utmost importance. Different parameters involved in the design of the 3D μPAD system and the colorimetric reaction conditions have been optimized. Under optimal conditions, detection limits of 0.004 mM and 0.013 mM were obtained for paracetamol and aspirin, respectively. The proposed procedure was validated against two certified reference materials and applied to the analysis of several synthetic urine and saliva samples. Synthetic urine and saliva samples were spiked at two concentration levels, showing recoveries in the range of 98–103% with a relative standard deviation of 3–6% (n = 6).