Vortex-Assisted Modified Dispersive Liquid-Liquid Microextraction of Trace Levels of Cadmium in Surface Water and Groundwater Samples of Tharparkar, Pakistan, Optimized by Multivariate Technique.

A simple vortex-assisted modified dispersive liquid-liquid microextraction procedure is proposed for the enrichment of cadmium (Cd+2) in surface (stored rainwater) and groundwater of the Tharparkar district in Pakistan, before analysis by flame atomic absorption spectrometry. Ammonium pyrrolidinedithiocarbamate was used as a ligand to make a hydrophobic complex of Cd+2, which was extracted in an ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate), and the nonionic surfactant Triton X-114 was applied as a dispersing medium. The contents of tubes were shaken for different time intervals on a vortex mixer to enhance extraction efficiency. A multivariate strategy was used to simultaneously evaluate seven factors including, concentration of the complexing reagent, pH, amounts of ionic liquid and Triton X-114, vortex shaking time, centrifugation time and extracting solution for their influence on the percentage recovery of the analyte. The important variables were further optimized by central composite design. The preconcentration factor and LOD were observed as 76.9 and 0.048 µg/L, respectively. The Certified Reference Material SRM1643e was used to check the validity of the developed method, and the RSD was found to be 4.02%. The proposed technique was successfully applied for the enrichment of Cd+2 in groundwater and surface water samples from the southeastern part of Pakistan. The observed results revealed that the concentration of Cd+2 in groundwater was higher than the World Health Organization recommended value of 3 µg/L for drinking water. For adults weighing approximately 60 kg, consumption of groundwater for drinking and other domestic purposes would provide levels of Cd+2 that are 2- to 3-fold higher than the provisional maximum tolerable daily intake.

Ultrasonically Dispersed Ionic Liquid-Based Microextraction of Lead in Biological Samples of Malnourished Children Prior to Analysis by Flame Atomic Absorption Spectrometry.

In the present study, a simple ultrasonically dispersed modified liquid-phase microextraction method was developed for the extraction of lead (Pb) from blood and scalp hair samples of malnourished children (MNC). The complexation of Pb was executed by means of the complexing agent, ammonium pyrrolidinedithiocarbamate (APDC), whereas extraction was carried out through the ionic liquid (IL), 1-butyl-3-methylimidazolium hexafluorophosphate. Ultrasound energy was used for the dispersion and extraction of the metal complex into an IL because it enhances the extraction of the metal complex into infinite IL drops at a temperature range of 40-80°C for 1-5 min. After sonication, the enriched analyte phase was separated by centrifugation. Nitric acid (HNO3; 0.5-2 mol/L) was added to the IL-enriched phase to back-extract the analyte into the acidic aqueous phase and analyzed by flame atomic absorption spectrometry. Various experimental parameters that affect the efficiency of the proposed method, such as volume of IL, concentration of the complexing agent, pH, ultrasonication time and temperature, and concentration of HNO3, were optimized. The enhancement factor was calculated as 70. The LOD for Pb ions was found to be 0.19 µg/L, with an RSD of <5%. Accuracy was ensured by applying the procedure to a certified reference material for whole blood and scalp hair. The developed procedure was successfully applied for the analysis of the concentration of Pb ion in whole-blood and scalp hair samples of MNC from different areas of Sindh, Pakistan. The concentration of Pb among MNC was 2-fold higher than the referent.

Interaction of Lead with Calcium, Iron, and Zinc in the Biological Samples of Malnourished Children.

Interaction between toxic and essential elements is of particular interest, because the deficiency of essential element can dramatically increase the absorption rate of toxic metals inside the body. This study was conducted to evaluate the possible correlation of lead (Pb) with calcium (Ca), iron (Fe), and zinc (Zn) in biological samples (whole blood and scalp hair) of malnourished children (MNC). For comparative purposes, age-matched, well-nourished children (WNC) were selected. The concentrations of understudy elements were analyzed by atomic absorption spectrophotometry after microwave acid digestion. The accuracy of the methodology, as well as its its validity and efficiency, was checked through certified reference material of whole blood and scalp hair. The result indicates that the MNC have a twofold higher level of Pb, while the levels of essential elements (Ca, Fe, and Zn) were onefold to twofold lower as compared to the WNC (p < 0.05). Significant negative correlations of Pb with Ca, Fe, and Zn were found in the studied malnourished population at p < 0.05. Further research studies are required to elucidate the role of these metals and the mechanism of interaction inside the body.

Application of ultrasonically modified cloud point extraction method for simultaneous enrichment of cadmium and lead in sera of different types of gallstone patients.

A novel and greener ultrasonically assisted/modified cloud point extraction procedure for the simultaneous preconcentration of lead and cadmium in serum samples of different types of gallstone patients was developed. The chelates of the under study metals, formerly formed with 8-hydroxyquinoline, were extracted in the micelles of a nonionic surfactant prior to analysis by flame atomic absorption spectrometer (FAAS). After the arrival of the cloud point, the critical micellar mass produced was homogenously dispersed in the aqueous phase with the help of ultrasound energy. The reliability of the developed procedure was tested by relative standard deviation (% RSD), which was found to be <5%. The performance of the proposed procedure was checked by applying to certified reference material and spiking standard in real samples. All the experimental parameters were optimized. The developed procedure of Um-CPE was applied successfully for the analysis of the target heavy metals in serum samples of different types of gallstone patients and referents. The higher levels of the understudy metals were observed in the patients as compared to the referents but the levels of the both metal were found to be considerably higher in patients with pigmented gallstones.