Faheem Shah

Cloud point extraction for determination of lead in blood samples of children, using different ligands prior to analysis by flame atomic absorption spectrometry: A multivariate study

The phase-separation phenomenon of non-ionic surfactants occurring in aqueous solution was used for the extraction of lead (Pb(2+)) from digested blood samples after simultaneous complexation with ammonium pyrrolidinedithiocarbamate (APDC) and diethyldithiocarbamate (DDTC) separately. The complexed analyte was quantitatively extracted with octylphenoxypolyethoxyethanol (Triton X-114). The multivariate strategy was applied to estimate the optimum values of experimental factors. Acidic ethanol was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometer (FAAS). The detection limit value of Pb(2+) for the preconcentration of 10 mL of acid digested blood sample was 1.14 μg L(-1). The accuracy of the proposed methods was assessed by analyzing certified reference material (whole blood). Under the optimized conditions of both CPE methods, 10 mL of Pb(2+) standards (10 μg L(-1)) complexed with APDC and DDTC, permitted the enhancement factors of 56 and 42, respectively. The proposed method was used for determination of Pb(2+) in blood samples of children with kidney disorders and healthy controls.

Environmental exposure of lead and iron deficit anemia in children age ranged 1–5 years: A cross sectional study

Iron (Fe) deficiency is the most common nutritional problem among children and lead (Pb) toxicity is the most common environmental health threat to children all over the world. The objective of this study was to determine blood lead (BPb) levels and prevalence of Fe deficient anemia among 1 to 5year old children attending day care clinic in pediatric ward of civil hospital Karachi, Pakistan. A total of 340 children of both genders participating in this study, were screened for anemia. Among them 215 were anemic and 125 non-anemic. The anemic group was further divided in two groups on the basis of % hemoglobin (Hb), mild (Hb <10g/dL) and severe anemic group (Hb <8g/dL), while non-anemic as referent children (Hb >10g/dL). The blood samples were analysed for Pb and Fe, along with hematological parameters. The result indicated that anemic children had a higher mean values of Pb in blood than referent children with Hb >10g/dL. The Pb levels <100μg/L were detected in 40% referent children while 60% of them had >10μg/dL. The BPb concentration in severe anemic children (53%) was found in the range of 100-200μg/L, whereas 47% had >200μg/L. The significant negative correlations of BPb level with % Hb (r=-0.514 and r=-0.685) and Fe contents (r=-0.522, r=-0.762, p<0.001) were observed in mild and severe anemic children respectively. While positive correlation was observed between BPb and age of both group and genders (r=0.69, p<0.01). The BPb levels were significantly associated with biochemical indices in the blood which have the potential to be used as biomarkers of Pb intoxication and Fe deficient anemia.

Simultaneously evaluate the toxic levels of fluoride and arsenic species in underground water of Tharparkar and possible contaminant sources: a multivariate study.

The present study investigated total arsenic (tAs), inorganic arsenic (iAs) species and fluoride ion (F(-)) contamination in underground water of Mithi and Nangarparkar subdistricts of Tharparkar, Pakistan. Statistical parameters, principal component analysis, cluster analysis, sodium absorption ratio and saturation indices (SI) were used to detect interrelation and sources of concentration of tAs, iAs species (As(3+) and As(5+)), F(-) and others physicochemical parameters. The concentration of As(3+) was measured by cloud point extraction using ammonium pyrrolidinedithiocarbamate (APDC) as complexing reagent, while inorganic arsenic (iAs) was determined by solid phase extraction, using titanium dioxide. The positive correlation was observed between F(-) contents with As species and other major ions, found in the underground water of the study area. The resulted data indicated that underground water samples of two areas of Tharparkar were severely contaminated with arsenic (0.100-3.83 mg/L) and fluoride ion (13.8-49.3mg/L), which were exceeded the World Health Organization provisional guideline values, 0.01 mg/L and 1.5mg/L, respectively. The SI of fluorite and calcite in the underground water samples showed that most of the samples were oversaturated with respect to calcite and fluorite.

Evaluation of arsenic levels in grain crops samples, irrigated by tube well and canal water

The aim of this study was to evaluate the uptake of arsenic (As) by grain crops (wheat, maize and sorghum) grown on agricultural soil irrigated with tube well water (SIT) as test samples and for comparative purposes, same grain crop samples grown on agricultural soil irrigated with fresh canal water (SIC) were marked as control samples, collected simultaneously from three sub-districts of Khairpur, Pakistan. Moreover, this paper demonstrated the total and EDTA (0.05 M) extractable As in both understudied soils that correlate with the respective total As in the edible parts of the studied grain crops. A significantly high accumulation of As was found in grains grown on SIT as compared to those grown on SIC. This study highlights the increased danger of growing food crops in the agricultural land continuously irrigated by As contaminated ground water.

Multivariate optimization of cloud point extraction procedure for zinc determination in aqueous extracts of medicinal plants by flame atomic absorption spectrometry.

Cloud point extraction method has been developed for preconcentration of trace quantities of zinc (Zn) in aqueous extract of medicinal plants and blood samples of liver cancer patients using flame atomic absorption spectrometry. The Zn in aqueous extracts of medicinal plants (MPs) was complexed with 2-methyl-8-hydroxyquinoline (quinaldine) and 1-(2-pyridylazo)-2-naphthol (PAN) separately and entrapped in a non-ionic surfactant Triton X-114. After centrifugation, the surfactant-rich phase was diluted with 0.25mL acidic ethyl alcohol. The multivariate strategy was applied to estimate the optimum values of experimental variables (pH, time temperature, ligands and surfactant concentrations). Interactions between analytical factors and their optimal levels were investigated by two level factorial designs. Students t-test on the results of factorial design with 16 runs for Zn extraction, demonstrated that the factors, ligands concentrations, pH and temperature were statistically significant. The accuracy was assessed by analysis of certified reference materials, namely, BCR 101 (spruce needles), Clincheck control-lyophilized human whole blood. Enhancement factor of 30 and 26 were achieved for the preconcentration of Zn by 2-methyl-8-hydroxyquinoline (L1) and 1-(2-pyridylazo)-2-naphthol (L2), respectively. The relative standard deviation for six replicate determinations of Zn at 10μg/L level using 2-methyl-8-hydroxyquinoline (L1) and 1-(2-pyridylazo)-2-naphthol (L2) were <4% and >5%, respectively.

Cloud point extraction of vanadium in pharmaceutical formulations, dialysate and parenteral solutions using 8-hydroxyquinoline and nonionic surfactant.

A cloud point extraction (CPE) method has been developed for the determination of trace quantity of vanadium ions in pharmaceutical formulations (PF), dialysate (DS) and parenteral solutions (PS). The CPE of vanadium (V) using 8-hydroxyquinoline (oxine) as complexing reagent and mediated by nonionic surfactant (Triton X-114) was investigated. The parameters that affect the extraction efficiency of CPE, such as pH of sample solution, concentration of oxine and Triton X-114, equilibration temperature and time period for shaking were investigated in detail. The validity of CPE of V was checked by standard addition method in real samples. The extracted surfactant-rich phase was diluted with nitric acid in ethanol, prior to subjecting electrothermal atomic absorption spectrometry. Under these conditions, the preconcentration of 50 mL sample solutions, allowed raising an enrichment factor of 125-fold. The lower limit of detection obtained under the optimal conditions was 42 ng/L. The proposed method has been successfully applied to the determination of trace quantity of V in various pharmaceutical preparations with satisfactory results. The concentration ranges of V in PF, DS and PS samples were found in the range of 10.5-15.2, 0.65-1.32 and 1.76-6.93 microg/L, respectively.

Simultaneous preconcentration of toxic elements in artificial saliva extract of smokeless tobacco product, mainpuri by cloud point extraction method.

It has been extensively investigated that smokeless tobacco chewing can lead mainly to inflammation of oral cavity. In present study, the total and artificial saliva extracted toxic elements, arsenic, cadmium, nickel and lead were estimated in smokeless tobacco product, mainpuri. Cloud point extraction has been used for the preconcentration of arsenic, cadmium, nickel and lead in artificial saliva extract, using complexing reagent, ammonium pyrrolidinedithiocarbamate. Total and extractable toxic elements were measured by electrothermal atomic absorption spectrometry. The chemical variables of cloud point extraction were optimized. The validity of methodology was tested by simultaneously analyzing certified reference material (Virginia tobacco leaves) and spike recovery test. The artificial saliva extractable levels of arsenic, cadmium, nickel and lead ranged from 15-22, 45-70, 35-58, and 18-32%, respectively, of total elemental contents in mainpuri samples. It was estimated that intake of 10g of different brands of mainpuri contributing the 5.88, 55.0, 45.0 and 40.3% of the provisional maximum tolerable daily intake for arsenic, cadmium, nickel and lead, respectively for adults of ~60kg.

Single step in-syringe system for ionic liquid based liquid microextraction combined with flame atomic absorption spectrometry for lead determination

A simple, novel and quick single step in-syringe system for ionic liquid based liquid microextraction (SSLME) has been presented in this paper. The objective of this study is to present a novel extraction alternative which avoids the centrifugation step, thermal dispersion and usage of hazardous organic solvents. In this procedure, the hydrophobic Pb–dithizone complex was extracted into the fine droplets of 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] within a syringe including Triton X-114 (TX-114) as dispersant. Several variables including pH of sample, [C4mim][PF6] volume, TX-114 volume, ligand concentration, incubation time and diluents nature were considered to be studied. At optimum experimental values of significant variables, detection limit and the enhancement factor were observed to be 0.281 μg L−1 and 82.6, respectively. The repeatability of the proposed method expressed as RSD (n = 5) was 3.51%. The validity of the developed method was checked out by Pb determination in certified reference material (TMDA-54.4 fortified lake water) and the results were found in good agreement with the certified values. The method was applied satisfactorily for the preconcentration of Pb in real samples.

Vortex-assisted liquid–liquid microextraction coupled to flame atomic absorption spectrometry for lead determination: ionic liquid based microextraction using Triton X-100 as dispersant

A simple liquid–liquid microextraction termed as vortex-assisted liquid–liquid microextraction (VLLME) coupled to flame atomic absorption spectrometry for lead (Pb) determination is achieved through phase-partitioning phenomena of ionic surfactants in aqueous solution. In this procedure, the hydrophobic chelate of Pb with 1-(2-pyridylazo)-2-naphthol (PAN) was extracted into the fine droplets of 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6], while using Triton X-100 (TX-100) as dispersing medium. Several variables including [C4mim][PF6] volume, pH of sample, TX-100 volume, concentration of PAN, centrifugation time and rate were considered to be studied. At optimum experimental values of significant variables, detection limit (LOD) and the enhancement factor (EF) were observed to be 0.307 μg L−1 and 54.2, respectively. The relative standard deviation (RSD) of 10 μg L−1 Pb was 4.09%. The coexisting ions showed no obvious negative outcome on Pb preconcentration. Validation of the developed method was carried out by Pb determination in “NIST-SRM 1515 Apple leaves” standard reference material and the results were found in good agreement with the certified values. The method was applied satisfactorily for the preconcentration of Pb in acid digested samples.

Preconcentration of lead from aqueous solution with activated carbon cloth prior to analysis by flame atomic absorption spectrometry: a multivariate study

In this work, the preconcentration of lead (Pb) was carried out by complexation with 2-(5-bromo-2-pyridilazo)-5-(diethylamino)phenol (5-Br-PADAP) and adsorption on an activated carbon cloth (ACC) prior to analysis by flame atomic absorption spectrometry (FAAS). The surface morphology of the ACC was studied by scanning electron microscopy and the adsorption capacity was determined by batch adsorption experiments. To evaluate the effects of several variables at once, the Plackett–Burman experimental design was used as a multivariate strategy. Important variables affecting the adsorption and preconcentration such as pH, ligand concentration, flow rate, eluent concentration and volume were investigated. No obvious negative effect of coexistent ions was observed. Validation was carried out by analyzing certified reference materials; sewage sludge (BCR 144R), human urine and whole blood. The proposed method was applied in the determination of Pb in tap water, urine and blood samples.