Aslıhan Arslan Kartal

A novel strategy for chromium speciation at ultra-trace level by microsample injection flame atomic absorption spectrophotometry

Simple, robust and novel analytical procedures were developed for the speciation of chromium by carrier element co-precipitation (CECP) and dispersive liquid–liquid microextraction (DLLME) coupled with microsample injection system–flame atomic absorption spectrophotometry (MIS–FAAS). Ammonium pyrrolidine dithiocarbamate (APDC), carbon tetrachloride and ethanol were used as chelating agent, extraction solvent and disperser solvent, respectively for the determination of Cr(VI) by DLLME. For total chromium, Cr(III) was oxidized by Ce(SO4)2 in acidic media (0.07 mol L−1 H2SO4) and the resulting solution was co-precipitated with APDC. The concentration of Cr(III) was estimated by determining the difference between the concentration of total chromium and that of Cr(VI). The maximum recovery of Cr(VI) was obtained with DLLME at optimal conditions of pH 3.0 , 0.25% APDC, 100 μL CCl4, 1.00 mL of CH3CH2OH and 0.01 mg L−1 Cr(VI). Whereas, the optimal conditions for CECP were 40 mL initial volume of water samples, 0.25% APDC, 0.02% Ce(SO4)2 and 0.10 mg L−1 Cr(VI) concentration. The limits of detection and enrichment factor of DLLME and CECP were [0.037 and 2.13] and [400 and 100] μg L−1, respectively with 40 mL initial volumes. The relative standard deviations (RSD, n = 6) were <4%. The proposed method was successfully applied to the chromium speciation at ultra-trace levels in natural drinking water, industrial effluents waste water and an exchangeable fraction of garden soil from Denizli. Moreover, the proposed methods compared well with the literature reported method.

Determination of Chlorophenols in Wastewater with Methyl Chloroformate Derivatization, Solid Phase Extraction, and Gas Chromatography–Mass Spectrometry

The determination of chlorophenols in wastewater with methyl chloroformate derivatization, solid phase extraction, and gas chromatography–mass spectrometry is reported. In order to employ this combined solid phase derivative extraction method, quantitative extraction was performed by the introduction of 100 mL of sample in 1.0 mol L−1 sodium hydroxide into a column containing 500 mg of packed resin at a flow rate of 1.0 mL/min. The chlorophenols were retained and derivatized quantitatively in the column by the introduction of 0.25 mL of methyl chloroformate. The derivatized analytes were eluted with 5.0 mL of hexane before the effluent was dried under a stream of nitrogen. The dried solution was diluted to a volume of 50 µL with hexane followed by analysis by gas chromatography–mass spectrometry. The preconcentration parameters were optimized and under these conditions: limits of detection from 0.010 to 0.423 µg L−1, a preconcentration factor of 2500, and precision values from 4.8 to 7.7% as the relative standard deviation were obtained. The method was employed for the analysis of water samples and the recoveries of the analytes were between 76 and 103%.

Determination of Chlorophenols and Alkylphenols in Water and Juice by Solid Phase Derivative Extraction and Gas Chromatography–Mass Spectrometry

A solid phase derivative extraction method using acetic anhydride was developed for the determination of chlorophenols and alkylphenols in water and fruit juice by gas chromatography–mass spectrometry (GC–MS). The quantitative extraction was performed by passing 100 mL of sample prepared in 0.1 mol L−1 sodium hydroxide through a column packed with 500 mg of a strong anion-exchange resin at a flow rate of 0.75 mL min−1. The retained phenols were quantitatively derivatized in the column by the introduction of 0.25 mL of acetic anhydride. The derivatized phenols were eluted with 3.0 mL of hexane and the effluent was dried under nitrogen. The final volume was diluted to fifty microliters with hexane and analyzed by GC–MS. Under the optimum conditions, preconcentration factors of 2000, limits of detection between 0.005 and 1.796 µg L−1, and relative standard deviations of 2.1% to 6.7% were obtained. The method was successfully applied to wastewater and fruit juice and the recoveries of phenols were between 76% and 111%.

Simultaneous Solid Phase Chelate Extraction for Ultratrace Determination of Copper, Nickel, and Zinc by Microsample Injection System Coupled Flame Atomic Absorption Spectrometry

A simple and accurate solid phase extraction method was developed for the determination of Cu(II), Ni(II), and Zn(II) at trace levels by microsample injection system coupled flame atomic absorption spectrometry. The proposed method is based on the retention of complexes of metal ions with 4-(2-pyridylazo) resorcinol on Amberlite XAD-7 resin and elution with acetone. The possible parameters influencing the preconcentration were optimized. The interferences of coexisting ions were studied. Under the optimal conditions, the detection limits of Cu(II), Ni(II), and Zn(II) were 0.058, 0.013, and 0.027 µg L−1, respectively. The applicability and the accuracy of the proposed method were validated by analysis of BCR 715 wastewater as a certified reference material and spiked real samples. Recoveries in the range of 94–105% were obtained with relative errors less than 7.5% and relative standard deviations less than 3.2%.

Dispersive Liquid–Liquid Microextraction of Nickel Prior to Its Determination by Microsample Injection System-Flame Atomic Absorption Spectrometry

A sensitive and simple method for the determination of trace nickel was developed by the combination of dispersive liquid–liquid microextraction (DLLME) and microsample injection system–flame atomic absorption spectrometry (MIS–FAAS). Trace nickel was preconcentrated as the 8-hydroxyquinoline chelate by DLLME, and the conditions were optimized by a Plackett-Burman design. Quantitative recovery of nickel (98 ± 1%) was obtained by a sample volume of 7.5 mL at a pH of 6.0. The enrichment factor was 52.5, and the limits of detection and quantitation were 0.1 µ g L−1 and 3.0 µ g L−1, respectively. The method was validated by the analysis of a wastewater standard reference material, water samples, and a wire sample. The reported method has superior analytical figures of merit compared with similar methods reported in the literature.

Synthesis and characterisation of novel chelating resin for selective preconcentration and trace determination of Pb(II) ions in aqueous samples by innovative microsample injection system coupled flame atomic absorption spectrometry

Expanded polystyrene (EPS) foam waste (white pollutant) was utilised for the synthesis of novel chelating resin i.e. EPS-N = N-α-Benzoin oxime (EPS-N = N-Box). The synthesised resin was characterised by FT-IR spectroscopy, elemental analysis, and thermogravimetric analysis. A selective method for the preconcentration of Pb(II) ions on EPS-N = N-Box resin packed in mini-column was developed. The sorbed Pb(II) ions were eluted with 5.0 mL of 2.0 mol L−1 HCl and determined by microsample injection system coupled flame atomic absorption spectrometry (MIS-FAAS). The average recovery of Pb(II) ions was achieved 95.5% at optimum parameters such as pH 7, resin amount 400 mg, flow rates 1.0 mL min−1 (of eluent) and3.0 mL min−1 (of sample solution). The total saturation capacity of the resin, limit of detection (LOD) and limit of quantification (LOQ) of Pb(II) ions were found to be 30 mg g−1, 0.033 μg L−1 and 0.107 μg L−1, respectively with preconcentration factor of 300. The accuracy, selectivity and validation of the method was checked by analysis of sea water (BCR-403), wastewater (BCR-715) and Tibet soil (NCS DC-78302) as certified reference materials (CRMs). The proposed method was applied successfully for the trace determination of Pb(II) ions in aqueous samples.

Determination of Pesticides in Soil by Mechanical Stirring-Assisted Extraction Coupled with Gas Chromatography-Mass Spectrometry

This work describes the development of an analytical method for determining the mobility of some organophosphorus and azole group pesticides. The chromatographic and mass spectrophotometric parameters were optimized. The target pesticides were recovered quantitatively (79.3–95.6%) with a relative standard deviation less than 8.5% at the optimum conditions of the extraction. The limits of detection of the target pesticides were found to be in the range of 0.16 to 1 . 14 µ g kg − 1 with a correlation coefficient ( r) > 0 . 9955 . The method was validated in the target environmental matrices by the analysis of a spiked soil sample. The proposed method was successfully applied for the determination of pesticides in vineyard soil samples and statistically evaluated.

Schiff base-functionalised styrofoam resin for preconcentration of metal ions in wastewater and wastewater-irrigated vegetables samples

Polystyrene (PS) was extracted from styrofoam waste and functionalised with schiff base, N,N-bis(salicylidene)cyclohexanediamine (SCHD) through an azo spacer. The resin was characterised and used for preconcentration of Pb(II), Ni(II) and Cd(II) ions prior to their trace determinations by microsample injection system–coupled flame atomic absorption spectrometry (MIS-FAAS). The recoveries of studied metal ions were achieved ≥96.0% with relative standard deviation (RSD) ≤4.5 at optimum parameters: pH 8; resin amount 300 mg; flow rates 3.0 mL min−1 of sample solution; and 2.0 mL min−1 of eluent (2.0 mol L−1 HNO3). The limits of detection (LODs) and limits of quantification (LOQs) were found to be 0.32, 0.23 and 0.21 and 1.10, 0.78 and 0.69 μg L−1, respectively, with preconcentration factors (PFs) of 500, 800 and 1000, respectively. The linear ranges of the method were 1–40, 1–25 and 1–20 μg L−1 for Pb(II), Ni(II) and Cd(II) ions, respectively. The accuracy and validation of the method were evaluated by analysis of certified reference materials (CRMs). The method was successfully applied for preconcentration of studied metal ions in wastewater and wastewater-irrigated vegetable samples.

Development of Dispersive Liquid-Liquid Microextraction for Determination of Some Chlorophenols in Water Samples by Gas Chromatography-Mass Spectrometry

Abstract A dispersive liquid-liquid microextraction (DLLME) procedure coupled with gas chromatography-ion trap mass spectrometric detection was developed for determination and preconcentration of some chlorophenols (CPs) from aqueous solutions. A Plackett-Burman experimental design was employed to evaluate the influence of those parameters to be controlled in DLLME. Under the optimum experimental conditions found from this statistical evaluation (sample volume, 10 mL; extraction solvent: chloroform, volume, 150 μL; disperser solvent: acetone, volume, 1000 μL; pH, 2; extraction time: 5 min.), the figures of merit of the proposed method were evaluated. A broad linear range (150–1200 μgL-1) was obtained with a good linearity (r2=0.999). The limits of detection varied between 0.010 and 0.226 μgL-1 for the CPs. Relative standard deviations obtained by extracting aqueous sample spiked at 150 μgL-1of each the CPs were almost 6.0 %. The relative recoveries of real water samples spiked with different concentrations of CPs were in the range of 60–113 %. The proposed DLLME method was successfully applied to the rapid and convenient determination of CPs in water samples.