Inorganic arsenic speciation in water samples by miniaturized solid phase microextraction using a new polystyrene polydimethyl siloxane polymer in micropipette tip of syringe system

The polymer, polystyrene polydimethyl siloxane was loaded into the micropipette tip of the syringe system as an adsorbent to developed miniaturized solid phase microextraction. Standard solutions of arsenate and arsenite were passed through the adsorbent loaded in micropipette tip to check the adsorption behaviors. It was observed that arsenate adsorbed on the polystyrene polydimethyl siloxane in the pH rang of 6–8, while arsenite was directly passed through the micropipette tip of syringe system. The adsorbed arsenate in micropipette tip of syringe system were eluted by 1.0 M hydrochloric acid. The total inorganic arsenic contents were obtained by the addition of oxidizing agent potassium permanganate into the studied samples before passing to the micropipette tip of syringe system. Arsenite concentration in water samples were measured by subtracting arsenate from total inorganic arsenic concentration. Different characteristics which effect the determination of arsenate specie like amount of adsorbent, adsorption capacity, pH, pulled and pushed cycles for adsorption and desorption, volume of sample, eluent type and it volume were also studied in detail. Enrichment factor and detection limit of arsenate by desired method were 218 and 6.9 ng L-1 respectively. The relative standard deviation was 4.1% (n=10, C=0.12 µg L-1). Accuracy of the desired technique was confirmed by analysis of the CRMs (Lake Ontario Water TM-28.3 and Riverine Water NRCC-SLRS-4). Desired technique was significantly useful for determination of the total arsenic, arsenate, and arsenite contents in different natural water samples. © 2016 Elsevier B.V.The author Jamshed Ali thanks to the Scientific and Technological Research Council of Turkey (TUBITAK) for awarding me “2216 Research Fellowship Program for Foreign Citizens” and providing financial support. The author also would like to thank to Gaziosmanpasa University for providing excellent research laboratory facilities to carry out this research work

Chromium speciation in water samples by loading a new sulfide-containing biodegradable polymer adsorbent in tip of the syringe system

A new adsorbent poly-3-hydroxybutyrate-2-(dodecylthiocarbonothioylthio)-2-methylpropionate triester (PH-DTT-MPT) was first time loaded in a micropipette tip for speciation of chromium in different water samples. Total chromium (Cr), trivalent chromium (Cr III ), and hexavalent chromium (Cr VI ) in different natural water samples were determined by electrothermal atomic absorption spectrometry. Known concentration of Cr III and Cr VI was passed through a biodegradable polymer for investigation of the behavior of the newly used adsorbent. The newly used copolymer absorbed the Cr III on surface of the PH-DTT-MPT at pH 7.0, while Cr VI was not adsorbed in desired pH value. After passing the real and standard solutions through the micropipette, then 2.0 mol L -1 HCl was used for elution of Cr III from the biodegradable polymer. Total Cr was calculated after reducing Cr VI into Cr III by specific concentration of hydroxy ammonium chloride (HONH 2 ·HCl). The concentration of Cr VI in different natural water samples was estimated after back calculation of Cr III from total chromium. Effect of analytical parameters like adsorbent, pH, eluent, sample volume, flow rates, and interfering ions was also studied. The LOD, LOQ, RSD, and EF of the developed method were calculated as 6.1 ng L -1 , 20 ng L -1 , 1.17%, and 90, respectively. Validation of developed method was checked by certified reference materials and spiking addition method. The developed method was successfully applied for determination of total Cr, Cr III , and Cr VI in various natural water ecosystems. © 2019, Springer Nature Switzerland AG.-72120514Funding information Author Jamshed Ali would like to thank the scientific and technological council of Turkey for the provided scholarship. The code of awarded scholarship is TUBITAK-2216 research fellowship program for foreigner citizens. We also thank the Bulent Ecevit University Research Funds (#BEU-2017-72118496-01) for financial support. Dr. Mustafa Tuzen thanks the Turkish Academy of Sciences for financial support

ISSN-1996-918X Pak

Abstract A green analytical procedure based on cloud point extraction (CPE) is proposed for arsenic determination in biological samples (scalp hair). The scalp hair samples were subjected to microwave assisted digestison in a mixture of nitric acid and hydrogen peroxide (2:1 ratio), prior to preconcentration by CPE. Arsenic in digested samples of scalp hair was formed complex with ammonium pyrrolidine dithiocarbamate (APDC), and resulted As-PDC complex was extracted by a non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114), after centrifugation the surfactant-rich phase was diluted with 0.1 mol L −1 HNO 3 in methanol. For optimum recovery of analyte, the influence of the analytical parameters including pH, amounts of complexing and surfactant reagents were investigated. An enrichment factor of 50 was obtained for the preconcentration of As. Limit of detection and quantitation obtained under the optimal conditions were 0.03 and 0.11 µg kg -1 , respectively. The obtained result showed sufficient recovery (> 98%) for As in certified reference material of human hair (BCR 397). The developed method was applied to the determination of As in scalp hair samples of male and female subjects of two villages of Hyderabad, Pakistan

Determination of Total Mercury in Muscle Tissues of Marine Fish Species by Ultrasonic Assisted Extraction Followed by Cold Vapor Atomic Absorption Spectrometry

A simple and rapid ultrasonic assisted extraction procedure (UEP) was developed for the determination of total mercury (Hg) in muscle tissues of marine fish species. For this purpose four fish species were collected from fish markets of Karachi, Pakistan. Total Hg concentration was determined by cold vapor atomic absorption spectrometry (CV-AAS), following UEP. Certified reference material DORM-2 (dogfish muscle) was used to validate the results. No significant difference was observed between the experimental results and the certified values of CRM (paired t-test). The limit of detection (LOD) and limit of quantitation (LOQ) of Hg were 0.133 and 0.445 µg/kg respectively. The Hg concentration in muscle tissues were obtained in the range of 0.721 – 1.41 mg/kg on dry weight. The contribution of the daily intake of Hg, based on the consumption of 250 g fresh fish muscles per day was found in the range of 0.615 – 1.22 µg/kg body weight/ day, which is greater than WHO permissible limit