New Analytical Methodology for Sb(III) Traces Quantification as Emergent Contaminant in Drinks Packaged PET Samples by Solid Surface Fluorescence

Emerging contaminants constitute a set of substances that are released into the environment for which regulations are currently not established for their environmental monitoring, being antimony one of them. A new methodology for Sb(III) traces monitoring by solid surface fluorescence is proposed. The metal was complexed with alizarine (Az) as fluorosphore reagent in alcaline medium in presence of the bile salt sodium cholate. To isolate the analyte of matrix constituents, a preconcentration/separation strategy on filter paper was introduced prior to determination step. The solid surface fluorescence was measured λem = 450 nm and λexc = 363 nm using a solid sampler holder. Under optimal conditions, the limits of detection and quantification of proposed methodology were 0.08 and 0.24 μg·L-1, respectively, showing a linear range from 0.24 to 304.4 μg·L-1 with good sensitivity and adequate selectivity. It was applied to the Sb(III) traces determination present in drinking water and beverages samples packaged in polyethylene terephthalate (PET) bottles widely consumed in Argentina. The combination of a preconcentration step on common filter paper and the inherent sensitivity of photoluminescent methods have permitted to achieve sensitivity similar to atomic spectroscopies using a lower price instrument typical in control laboratories. Precision and accuracy were tested with excellent agreement. Results were truenessed by ETAAS with satisfactory concordance.

Direct Cadmium Monitoring in Cigarette Filters Leachate by Molecular Fluorescence

This work proposes a new direct flourimetric methodology for cadmium traces quantification based on its association with azo-reagent SPADNS and rhodamine B dye. Experimental variables that influence on fluorimetric sensibility were optimized using uni-variation assays. The calibration graph using zeroth order calibration was linear from 0.192 to 1.26 104 μg.L-1, with a correlation coefficient of 0.99. Under the optimal conditions, it was obtained a limit of detection of 0.057 μg.L-1 and a limit of quantification of 0.192 μg.L-1. The method showed good sensitivity, adequate selectivity with good tolerance to foreign ions, and was applied to the determination of trace amounts of cadmium in filters leachates coming from unsmoked, automatically smoked and smokers smoked cigarettes with satisfactory results. The proposed method represents an innovative application of luminescence to metal analysis comparable in sensitivity and accuracy to atomic spectroscopies.

Green Photoluminescent Methodology for Aluminium Traces Quantification in 24-Hour Urine of Subjects with Different Exposition to Tobacco Smoke

The aim of this work has been to evaluate the aluminium (Al(III)) traces contents in 24-hour urine samples from subjects with different tobacco smoke expositions using a new methodology with 1,4-dihydroxy-9, 10-anthraquinone (Quinizarine, QZ) as a fluorosphore. Biological samples were tested using commercial reagent strips and clinical parameters. Al(III) was determined complexing with QZ followed by a solid phase extraction step using Nylon membranes as a solid support. The analyte was subsequently quantified by solid surface fluorescence (SSF, λem= 573, λexc= 490) with a detection limit of 0.88 μg L-1 and quantification limit of 2.69 μg L-1. The calibration curve was linear from 2.69 to 499.13 μg L-1 Al(III) (R2 = 0.9973). Urine samples were successfully analysed with an average recovery close to 100%. Solid phase extraction step showed efficacy to eliminate foreign ions and the highly fluorescent matrix own of urine. Results were validated by electrothermal atomic absorption spectrometry (ETAAS) with an adequate concordance. The new methodology has low operation cost with simple instrumentation and without organic solvent.