Determination Of Zinc In Water Research Articles

Efficiency enhancement of the spectrophotometric determination of Zinc in water, food and pharmaceutical preparations samples using Cloud Point Extraction

Efficiency enhancement of the spectrophotometric determination of Zinc in water, food and pharmaceutical preparations samples using Cloud Point Extraction

Comprehensive Assessment of Flow and Other Analytical Methods Dedicated to the Determination of Zinc in Water.

An original strategy to evaluate analytical procedures is proposed and applied to verify if the flow-based methods, generally favorable in terms of green chemistry, are competitive when their evaluation also relies on other criteria. To this end, eight methods for the determination of zinc in waters, including four flow-based ones, were compared and the Red–Green–Blue (RGB) model was exploited. This model takes into account several features related to the general quality of an analytical method, namely, its analytical efficiency, compliance with the green analytical chemistry, as well as practical and economic usefulness. Amongst the investigated methods, the best was the flow-based spectrofluorimetric one, and a negative example was that one involving a flow module, ICP ionization and MS detection, which was very good in analytical terms, but worse in relation to other aspects, which significantly limits its overall potential. Good assessments were also noted for non-flow electrochemical methods, which attract attention with a high degree of balance of features and, therefore, high versatility. The original attempt to confront several worldwide accepted analytical strategies, although to some extent subjective and with limitations, provides interesting information and indications, establishing a novel direction towards the development and evaluation of analytical methods.

Automated analytical procedure using multicommuted flow analysis and organic solvent extraction controlled by an Arduino Due board for photometric determination of zinc in water

In this study, an automated analytical procedure that utilizes solvent extraction for the photometric determination of zinc in water is described. The procedure involved the reaction of diphenylthiocarbazone (dithizone) with Zn(II) in the alkaline medium and extraction with chloroform. The instrumental setup, combined with flow-batch and multicommuted flow analyses approaches, was designed to facilitate microextraction without using a dispersant organic solvent. Fluid propulsion occurred through two mini peristaltic pumps and a homemade syringe pump. Photometric detection was performed using a homemade LED-based photometer equipped with a flow cell (50 mm in length). The control of the instrumental setup, analytical procedure, and data acquisition algorithm was achieved using an Arduino Due board along with a software developed for this study. After determining the optimal values of the control variables using Zn(II) standard solutions, the effectiveness of the proposed method was evaluated. For this purpose, a set of water samples was analyzed. For assessing accuracy, the samples were also analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES). By comparing the paired t-test results of the two analyses, it was observed that at 95% confidence level, there is no significant difference. Other advantageous results of the proposed method were as follows: the linear response range was 10–100 µgL−1 (r2 = 0.9934), the limit of detection was 8.3 µgL−1, the coefficient of variation was 3.3% (n = 9), the consumption of chloroform and dithizone was 200 µL and 4 µg, respectively, per determination, and the sampling rate was 19 determinations per hour.

Solid Phase Extraction Utilization for Colorimetric Determination of Zinc in Waters, Food, Milk, and Biological Samples

Solid Phase Extraction Utilization for Colorimetric Determination of Zinc in Waters, Food, Milk, and Biological Samples

Solid Phase Extraction Utilization for Colorimetric Determination of Zinc in Waters, Food, Milk, and Biological Samples

A highly rapid, sensitive, and selective method for the determination of zinc based on the reaction of zinc(II) with 5-amino-2-(phenyldiazenyl)phenol (ACDP) and/or 5-amino-2-(p-tolyldiazenyl)phenol (ATDP) and the solid phase extraction of the Zn(II)- ACDP and/or ATDP complex with Amberlite XAD-2000 was developed, in the presence of pH = 5.6 and 6.2 using ACDP and ATDP, respectively, and Triton X-114 medium. ACDP and/or ATDP reacts with zinc to form a violet complex with a molar ratio of 2:1 (ACDP and/or ATDP to zinc). This complex was enriched by the solid phase extraction with Amberlite XAD-2000. An enrichment factor of 500 was obtained by elution of the complex from the resin with a minimal amount of isopentyl alcohol (0.2 ml). In isopentyl alcohol medium, the molar absorptivity of the complex is 1.13 × 10⁶ and 1.37 × 10⁶ L/mol cm at 647 and 662 nm using ACDP and ATDP, respectively, against a reagent blank prepared in a similar way without zinc. Beer's law is obeyed in the range of 5.0-160 ng/ml in the measured solution. The relative standard deviation for 10 replicate samples of 50 ng/ml level is 1.26 and 1.47%, respectively. The detection and quantification limits reaches 1.5 and 4.7 ng/ml in the original samples. The presented procedure was successfully applied for determination of zinc content in real samples such as waters, food, milk, and biological samples with satisfactory results.

Solid Phase Extraction Utilization for Colorimetric Determination of Zinc in Waters, Food, Milk, and Biological Samples

Solid Phase Extraction Utilization for Colorimetric Determination of Zinc in Waters, Food, Milk, and Biological Samples

On-line Determination of Zinc in Water and Biological Samples after Its Preconcentration onto Zincon Anchored Polyurethane Foam.

A fast and sensitive on-line procedure for the determination of zinc in water and biological samples was developed. Zinc was preconcentrated in a mini-column packed with polyurethane foam (PUF) chemically modified with zincon via -N=N- bonding. The optimal conditions for preconcentration were pH 8.5 and sample flow rate of 4.0 mL min(-1). Quantitative desorption of Zn(II) was obtained by 0.1 mol L(-1) hydrochloric acid and subsequent spectrophotmetric determination using 4-(2-pyridylazo)-resorcinol at 498 nm. The obtained detection limit was found to be 3.0 ng mL(-1), precision (RSD) was 4.8 and 6.7% at 20 and 110 ng mL(-1), respectively, for 60 s preconcentration time and enrichment factor was 31. The linearity range was from 10 to 120 ng mL(-1) and maximum sample throughput was 20 h(-1). Finally, the method was successfully applied to the determination of zinc in tap water, Nile River water and human urine samples with RSD in the range of 1.1 - 8.3%.

Determination of Trace Zinc in Water by Flame Atomic Absorption Spectrometry After Preconcentration by Modified Organobentonite with 1-(2-Pyridylazo)-2-naphthol

Determination of Trace Zinc in Water by Flame Atomic Absorption Spectrometry After Preconcentration by Modified Organobentonite with 1-(2-Pyridylazo)-2-naphthol

Modified ionic liquid cold-induced aggregation dispersive liquid-liquid microextraction followed by atomic absorption spectrometry for trace determination of zinc in water and food samples

We report on a new method for the microextraction and determination of zinc (II). The ion is accumulated via ionic-liquid cold-induced aggregation dispersive liquid-liquid microextraction (IL-CIA-DLLME) followed by flame atomic absorption spectrometry (FAAS). The ionic liquid (IL) 1-hexyl-3-methylimidazolium hexafluorophosphate is dispersed into a heated sample solution containing sodium hexafluorophosphate as a common ion source. The solution is then placed in an ice-water bath upon which a cloudy solution forms due to the decrease of the solubility of the IL. Zinc is complexed with 8-hydroxyquinoline and extracted into the IL. The enriched phase is dissolved in a diluting agent and introduced to the FAAS. The method is not influenced by variations in the ionic strength of the sample solution. Factors affecting the performance were evaluated and optimized. At optimum conditions, the limit of detection is 0.18 μg L−1, and the relative standard deviation is 3.0% (at n = 5). The method was validated by recovery experiments and by analyzing a certified reference material and successfully applied to the determination of Zn (II) in water and food samples.

A novel microextraction technique based on 1-hexylpyridinium hexafluorophosphate ionic liquid for the preconcentration of zinc in water and milk samples

A simple dispersive liquid–liquid microextraction methodology based on the application of 1-hexylpyridinium hexafluorophosphate [HPy][PF 6] ionic liquid (IL) as an extractant solvent was proposed for the preconcentration of trace levels of zinc as a prior step to determination by flame atomic absorption spectrometry (FAAS). Zinc was complexed with 8-hydroxyquinoline (oxine) and extracted into ionic liquid. Some effective factors that influence the microextraction efficiency such as pH, oxine concentration, amount of IL, ionic strength, temperature and centrifugation time were investigated and optimized. In the optimum experimental conditions, the limit of detection (3 s) and the enhancement factor were 0.22 μg L −1 and 71, respectively. The relative standard deviation (RSD) for six replicate determinations of 13 μg L −1 Zn was 1.92%. In order to validate the developed method, a certified reference material (NIST SRM 1549) was analyzed and the determined values were in good agreement with the certified values. The proposed method was successfully applied to the trace determination of zinc in water and milk samples.

Application of Box–Behnken design in the optimization of a magnetic nanoparticle procedure for zinc determination in analytical samples by inductively coupled plasma optical emission spectrometry

This article describes the development of a procedure for zinc determination in water and biological samples after extraction by magnetic nanoparticles by inductively coupled plasma optical emission spectrometry (ICP-OES). The optimization strategy was carried out by using two level full factorial designs. Results of the two level full factorial design (2 4) based on an analysis of variance demonstrated that only the pH, amount of extractant and amount of nanoparticles were statistically significant. Optimal conditions for three variables: pH of solution, amount of extractant ( E), and amount of nanoparticles ( N) for the extraction of zinc samples were obtained by using Box–Behnken design. These values were 3.8, 3.1 and 3.3 mg, for pH of solution, amount of nanoparticles and amount of extractant, respectively. Under the optimized experimental conditions, the detection limit of the proposed method followed by ICP-OES was found to be 0.8 μg L −1. The method was applied to the determination of zinc in water and biological samples.

The determination of zinc in water by flame atomic absorption spectrometry after its separation and preconcentration by malachite green loaded microcrystalline triphenylmethane

A new method for the separation and preconcentration of zinc using microcrystalline triphenylmethane loaded with malachite green was developed prior to the determination by FAAS. The effects of different parameters, such as the amounts of malachite green, NH 4SCN and triphenylmethane, stirring time and various metal ions on the enrichment yield of zinc have been studied to optimize the experimental conditions. Under the optimum conditions, zinc can be adsorbed on the surface of microcrystalline triphenylmethane loaded with malachite green. The possible reaction mechanism for the preconcentration of zinc was discussed in detail in this paper. Zn(II) can be completely separated from Pb(II), Ni(II), Co(II), Cd(II), Mn(II), Cr(III), Cu(II), Fe(III) and Al(III) in the solution. The detection limit of this proposed method for zinc is 0.05 μg L −1 with preconcentration factor of 200. The recovery is in the range of 96.5–105%. The relative standard deviation is 1.0–3.1%. Analytical results obtained with this novel method are very satisfactory. The proposed method was successfully applied to the determination of trace zinc in various water samples by FAAS after preconcentration using microcrystalline triphenylmethane.

Atomic-absorption determination of zinc in water with micellar-extraction preconcentration with phases of nonionic surfactants

Effects of various factors on the extraction of zinc with carboxylic acids and their mixtures with amines into a micellar phase of a nonionic surfactant at the cloud point were studied. The conditions for the atomic-absorption determination of zinc preconcentrated into an OP-10 phase on heating with capric acid and n-octylamine were developed.

Online Flow-Injection Determination of Trace Zinc in Natural Waters

A procedure for the flow-injection determination of trace zinc in natural waters with sorption preconcentration is developed. The procedure provides the determination of zinc in the concentration range from 5 to 100 μg/L with RSD no higher than 25%. A single determination of zinc in water at the lower limit of analytical range takes 15 min.

Application of Doehlert matrix and factorial designs in the optimization of experimental variables associated with the on-line preconcentration and determination of zinc by flow injection inductively coupled plasma atomic emission spectrometry

A simple and rapid method is described for the preconcentration and determination of zinc in waters. The method employs on-line preconcentration of zinc on a 3 cm × 3 mm column packed with silica gel functionalized with 1,5-bis(di-2-pyridyl)methylene thiocarbohydrazide (DPTH-gel) and placed in the injection valve of a simple flow manifold. Five variables (sample flow rate, eluent flow rate, eluent concentration, pH and buffer concentration) were considered as factors in the optimization process. Interactions between analytical factors and their optimal levels were investigated using two level factorial and Doehlert matrix designs. The optimum conditions established were applied to the determination of zinc by flow injection inductively coupled plasma atomic emission spectrometry. The proposed method has a linear calibration range from 2 to at least 500 ng ml−1 of zinc, with a detection limit of 1.7 ng ml−1 (S/N = 3) and a throughput of 40 samples h−1 using a 60 s preconcentration time.Validation was carried out against certified reference water samples, and by determining the analyte content in sea water and synthetic sea water. The results showed good agreement with the certified values and sufficiently high recoveries.

On-line preconcentration system for flame atomic absorption spectrometry using unloaded polyurethane foam: determination of zinc in waters and biological materials

An on-line procedure for the preconcentration and determination of zinc in waters and biological materials was developed. Zinc is preconcentrated from acidic medium (pH 3.0) as its thiocyanate complex onto a polyurethane foam mini-column placed in the loop of a four-way valve. The elution step is performed with a stream of 30% acetone in 2% HNO3 and the zinc displaced is introduced directly into the nebuliser of a flame atomic absorption spectrometer. The system was operated under two different preconcentration times since the concentration of zinc in the two types of samples was different. For biological samples, 1 min was used and a detection limit of 3.0 µg L–1 was achieved with a throughput of 40 samples per hour. At a concentration of 20 µg L–1, an RSD of 2.5% was obtained. For the determination of zinc in natural water, a preconcentration time of 3 min was employed and a detection limit of 0.85 µg L–1 was obtained. In this case, the system was slower with a throughput of 17 samples per hour. The RSD at 10 µg L–1 was 6.0%. The continuous flow system was applied to the analysis of several biological reference materials and natural water samples.

Colorimetric Determination of Zinc in Water by Zincon

The methods which have been used for the determination of zinc in water are not adequate in the sensibility and procedure. It was found that the application of zincon (2-carboxy-2'-hydroxy-5-sulfoformazyl-benzene) introduced by Yoe and Rush is most suitable for the determination of zinc in water. Copper also forms a blue complex with zincon. Good result was obtained by the addition of 1 g of thiourea for masking 100 μg of copper presented with 10μg of zinc. In the presence of much iron (III), aluminium, copper and mercury (II), it is necessary to extract zinc from a weakly ammonical solution with dithizon-CCl4 solution, and to shake the extract with dilute HCl (0.02 N) to bring zinc into the aqueous phase.