Taj Muhammad Jahangir

Background: 5-Fluorouracil (5-FU) is correlated as a structural derivative of the nucleobase uracil; it is widely used as an anti-cancer drug in

The work examines the determination of gold from environmental samples by dispersive liquid–liquid microextraction (DLLME) method. The method was developed for the separation and determination of Au (III) ions after chelating with bis (salicylaldehyde) ethylenediimine (H₂SA₂en) Schiff-base as derivatizing reagent. Flame atomic absorption spectrometry (FAAS) and inductively coupled plasma-optical emission spectrometry (ICP-OES) techniques were used for quantitation of Au (III). These techniques are sensitive and rapid for the determination of gold concentrations in ore, water and sediment samples. The influence of factors such as pH, reagent concentration, solvents (extracting) (disperser) and solvent volumes on extraction efficiency of Au (III) ions were studied and optimized by univariate and multivariate techniques. The linearity of the method was in the range of 2 to 12 µg/L with R² = 0.997. The limit of detection was 1 µg/L, and the limit of quantification was 3 µg/L. The preconcentration factor and enrichment factor values were 44 and 47. The repeatability (the intra-day) and reproducibility (the inter-day) precisions (n = 3) were found to be 0.417–3.56%. The proposed method was successfully applied for the determination of gold in sediment samples of the Indus River, Kori Barrage, goldsmith water, acidic solution of goldsmith and ornament samples collected from Goldsmith Labs and shops. The results found from FAAS were compared with those obtained from ICP-OES technique, and a good correlation with comparable selectivity and sensitivity was specified.

Sanghar District is located in the central part of Sindh Province and shares a boarder with India to the east. This work examines the water quality of the groundwater of three subdistricts, Sanghar, Khipro, and Jan Nawaz Ali, mostly used for human consumption, cattle farming, and irrigation. A total of 74 representative samples were collected and analyzed for 26 different parameters, including anions, cations, trace, and toxic elements. The total dissolved salts (TDSs) contained in 41 samples (55.4%), the major cations, K, Na, Mg, and Ca, in 44.6–93.2% of samples, and the major anions, Cl, HCO₃, and SO₄, in 68.6–81.0% of samples were within the permissible guidelines of the World Health Organization (WHO). The samples containing elements Cr (24.0%), Pb (29.7%), Ni (39.2%), Cd (40.5%), As (10.8%), and F (39.18%) were above the permissible limits of the WHO. The groundwater samples were examined for water quality index (WQI), contamination index (C_d), chronic daily intake indices (CDIs), hazard quotient indices (HQ), principal component analysis (PCA), piper diagrams, Gibbs diagrams, and cluster analysis to ascertain nature of the groundwater present in the study area. The samples were also examined for suitability for irrigation by sodium percentage (Na%), sodium adsorption ratio (SAR), Kelly’s index (KI), permeability index (PI), and Wilcox diagrams. Samples in the range of 0 to 58.33% were inappropriate for irrigation.

The dispersive liquid–liquid microextraction methods were developed, based on the enrichment and separation of copper after complexation with bis(salicylaldehyde)ethylenediamine (H₂SA₂en) from environmental samples. The quantitation was made by the flame atomic absorption spectrometric methods. The effect of parameters pH, derivatising reagent (H₂SA₂en) concentration, the volume, extracting solvent, disperser solvent, centrifugation time and temperature on analytical signals and the extraction efficiency of metal ion was examined and optimised using univalent and multivalent (factorial design) techniques. The linearity of calibration curve was in the range of 5–30 ng/ml with R² = 0.9907. Limit of detection was 2.0 ng/ml and limit of quantification was 6.0 ng/ml, and the enrichment factor (21.5), repeatability (n = 4) and robustness of the determination were also evaluated. Method was effectively employed for the estimation of copper from the samples of water and sediments. Samples were collected from Darawat Dam and River Indus. The results obtained were matched with reported methods, and comparable sensitivity and selectivity was indicated.