ABSTRACT
Metals may be released from toys via saliva during mouthing, via sweat during dermal contact, or via gastric and intestinal fluids after partial or whole ingestion. In this study, we determined the lead migration from toys bought on the Portuguese market for children below 3 years of age. The lead migration was performed according to the European Committee for Standardization EN 71-3, which proposes a 2-hour migration test that simulates human gastric conditions. The voltammetric determination of migrated lead was performed by anodic stripping voltammetry (ASV) at a bismuth film electrode (BiFE). For all the analyzed toys, the values of migrated lead did not exceed the limits imposed by the European Committee for Standardization EN 71-3 (90 mg kg-1) and by the EU Directive 2009/48/EC (13.5 mg kg-1) on the safety of toys.
Subject(s)
Environmental Pollutants/analysis , Lead/analysis , Play and Playthings , Bismuth/chemistry , Child, Preschool , Electrochemical Techniques , Electrodes , Humans , Infant , Infant, Newborn , PortugalABSTRACT
An automatic system was developed to determine ofloxacin in biological fluids and pharmaceutical formulations. Drug detection was carried out by a potentiometric membrane sensor based on [bis(trifluoromethyl)phenyl]borate as molecular-recognition material. The tubular shaped detector system was solidly attached to the manifold, creating a high-throughput stable setup (50 samples per hour) appropriate for routine antibiotic assessment. Under the optimized flow conditions, the sensor displayed a mean detection limit of 1 × 10(-5) M, a linear response over the concentrations of 2 × 10(-5) to 5 × 10(-3) M (slope of 57.4 mV decade(-1)) and a wide working pH range (2.1 - 6.6). The procedure was successfully applied to ofloxacin analysis in pharmaceuticals (relative deviation lower than 6%) and biological fluids at levels usually found after drug administration of clinical doses (recoveries between 91 and 106%). No significant interference from common excipients found in commercial formulations and inorganic ions usually present in biological fluids was noticed.
Subject(s)
Ofloxacin/blood , Ofloxacin/urine , Pharmaceutical Preparations/chemistry , Potentiometry , Automation/instrumentation , Humans , Molecular Structure , Ofloxacin/analysis , Potentiometry/instrumentationABSTRACT
Two quasi-independent methods for potentiometric and optical determination of chloride were simultaneously implemented in a flow system, providing real-time assessment of the quality of results. A potentiometric and an optical polymeric membrane doped with the same indium(III) octaethyl-porphyrin were used as sensor ionophore. The working mechanism and the analytical characteristics of these porphyrin-based sensors with respect to dynamic range, selectivity, repeatability and lifetime are discussed. These sensors, utilised as detectors in a flow system, were applied for the analysis of chloride in pharmaceutical solutions. The quality of the results obtained was evaluated by comparison with those provided by the reference method and no significant statistical differences at the 95% confidence level were observed. The simultaneous attainment of two measurements permitted the standardisation of results in real time and the detection of failures in the procedure.
Subject(s)
Chlorides/analysis , Ion-Selective Electrodes , Membranes, Artificial , Metalloporphyrins/chemistry , Calibration , Flow Injection Analysis/methods , Ionophores , Pharmaceutical Preparations/chemistry , Polyvinyl Chloride , Potentiometry/methods , Reference Standards , Reproducibility of Results , Sensitivity and Specificity , Spectrophotometry, Ultraviolet/methodsABSTRACT
Two almost independent potentiometric methods were implemented in a multi-task flow system based on the concept of sequential injection analysis for the analytical control of potassium clavulanate in pharmaceutical formulations. In addition to in-line preparation of the solutions submitted to the analysis, the system simultaneously detected the clavulanate anion and the potassium cation using two potentiometric detectors selective to each of the species referred. For the two determinations, the system developed presented an analytical range of 2 mM-0.1 M. Relative standard deviations of 0.5 and 0.6%, respectively, for clavulanate and potassium, were calculated from the signals obtained for 10 consecutive injections of a solution of 5x10(-3) M potassium clavulanate. The frequency of sampling was 53 samples h(-1). The quality of results supplied was evaluated by comparison with the reference procedure revealing relative errors less than 2% for the two determinations. The simultaneous attainment of two measurements permitted the standardisation of results in real time, the detection of faults in the procedure and monitoring the chemical stability of clavulanate.
