Acetaminophen (AC) is a frequently used pharmaceutical which has been detected in water systems and is of concern due to its potential environmental impacts. In this study, three quantum dot (QD)-ligand systems, namely L-cysteine (L-cys)-, N-acetyl-L-cysteine (NAC)- and glutathione (GSH)-capped CdSe/ZnS quantum dots, were synthesized and tested for the fluorescence detection of acetaminophen. Among the synthesized aqueous core/shell quantum dots, L-cys-CdSe/ZnS QDs were found to be optimal with high sensitivity for the fluorescence detection of acetaminophen. The L-cys-CdSe/ZnS QDs were of a zinc blende crystal structure and displayed excellent fluorescence intensity and photostability and provided a photoluminescence quantum yield of 77 % . The fluorescence of L-cys-CdSe/ZnS QDs was enhanced by the introduction of AC enabling the development of a fast and simple method for the detection of AC. Under optimal conditions, F-F0 was linearly proportional to the concentration of AC from 3.0-100 nmol L-1 with limits of detection and quantification of 1.6 and 5.3 nmol L-1, respectively. Some related pharmaceutical compounds including epinephrine hydrochloride (EP), L-ascorbic acid (AA), uric acid (UA), dopamine hydrochloride (DA) and 4-aminophenol (4-AP) did not interfere with the sensing of AC. The probe was also successfully applied in the determination of AC in tap and river water matrices.

In this work, a spectrophotometric methodology was applied in order to determine epinephrine (EP), uric acid (UA), and acetaminophen (AC) in pharmaceutical formulations and spiked human serum, plasma, and urine by using a multivariate approach. Multivariate calibration methods such as partial least squares (PLS) methods and its derivates were used to obtain a model for simultaneous determination of EP, UA and AC with good figures of merit and mixture design was in the range of 1.8 - 35.3, 1.7 - 16.8, and 1.5 - 12.1 µg mL-1. The 2nd derivate PLS showed recoveries of 95.3 - 103.3, 93.3 - 104.0, and 94.0 - 105.5 µg mL-1 for EP, UA, and AC, respectively.