A Simple and Highly Structured Procaine Hydrochloride as Fluorescent Quenching Chemosensor for Trace Determination of Mercury Species in Water

An ultrasensitive, simple and highly selective spectrofluorometric strategy for quantifying traces of mercury(II) in environmental water has been established using the fluorescent probe procaine hydrochloride (PQ+.Cl-). The procedure was based upon the formation of the ternary ion associate complex [(PQ+)2.(HgI4)2-] between PQ+.Cl- and mercury(II) in iodide media at pH 9.0-10.0 with its subsequent extraction onto dichloromethane accompanied by a change in fluorescence intensity at ?ex/em = 268/333 nm. The developed strategy exhibited a linear range of 1-114 ?g L-1 with lower limit of detection (LOD) and quantification (LOQ) of mercury(II) 1.3 and 3.98 nM, respectively. Intra and inter-day laboratory accuracy and precision for trace analysis of mercury(II) in water were performed. Complexed mercury(II) in environmental water, chemical speciation and successful literature comparison was performed. The proposed system offered excellent selectivity towards mercury(II) ions examined in the presence of competent ions in excess, relevant to real water samples. The method was applied for analysis of mercury(II) in tap water samples. Statistical comparison (Student's t and F tests) of the proposed method with the reference ICP-OES method revealed no significant differences in the accuracy and precision.