Determination of trace amounts of lead by adsorptive cathodic stripping voltammetry with L-3-(3,4-Dihydroxyphenyl)alanine

2009 ◽  
Vol 74 (4) ◽  
pp. 599-610 ◽  
Author(s):  
Mohammad Bagher Gholivand ◽  
Alireza Pourhossein ◽  
Mohsen Shahlaei

A sensitive and selective procedure is presented for the voltammetric determination of lead. The procedure involves an adsorptive accumulation of lead L-3-(3,4-dihydroxyphenyl)alanine (LDOPA) on a hanging mercury drop electrode, followed by a stripping voltammetric measurement of reduction current of an adsorbed complex at –0.15 V (vs Ag|AgCl). Optimum conditions for lead analysis include pH 8.5, 80 μM LDOPA and accumulation potential –0.15 V (vs Ag|AgCl). The peak currents are proportional to the lead concentration 1–300 nmol l–1 with a detection limit of 0.6 nmol l–1 and accumulation time 60 s. The method was used for the determination of lead in blood, dry tea and also in waters.

2013 ◽  
Vol 78 (5) ◽  
pp. 717-724 ◽  
Author(s):  
Foroozan Hasanpour ◽  
Hossein Teimori ◽  
Masoud Fouladgar ◽  
Masoumeh Taei

A sensitive and selective procedure is presented for voltammetric determination of cobalt. The procedure involves an adsorptive accumulation of cobalt pyrogallol red (PGR) complex on stationary mercury drop electrode, followed by cathodic stripping voltammetry measurement of reduction current of adsorbed complex at -1.17 V (vs. Ag/AgCl). The optimum conditions for determination of cobalt include pH 11.0, 35 ?M pyrogallol red, an accumulation potential of -0.9 V (vs. Ag/AgCl) and scan rate 80 mVs-1. The peak current is proportional to the concentration of cobalt over the concentration range of 5.0 to 280 ng mL-1 with a detection limit of 1 ng mL-1 with an accumulation time of 140 s. The method was applied for the determination of cobalt in analytical grade NaCl and water samples.


2012 ◽  
Vol 5 (2) ◽  
pp. 100
Author(s):  
Deswati ◽  
Hamzar Suyani ◽  
Umiati Loekman ◽  
Nilam Sari

A selective and sensitive adsorptive stripping voltammetric (AdSV) method for simultaneous determination of lead(II) and cadmium(II) were proposed. The aim of this study was to get the optimum condition for simultaneuos determination of lead(II) and cadmium(II). The parameters were studied such as: variation of accumulation potential, accumulation time, pH, and variation ofcalcon concentration. In this case, the optimum conditions were reached at accumulation potential –0.7 V, accumulation time 80 s, concentration of 0.12 mM calcon, and pH 7.0. At the optimumconditions the relative standard deviation were 2.90% and 1.46% for Pb(II) and Cd(II) respectively for eight replicates (n = 8) measurements. The method was applied for the direct determination of Pb(II) and Cd(II) in sea water around Bungus, Padang City. Concentration Pb(II) and Cd(II) insample were 9.918 μg/L – 27.320 μg/L for Pb(II) and 7.997 μg/L - 32.521 μg/L for Cd(II), with recovery of 99.48%, and 103.28 for Pb(II), and Cd(II) respectively.


2015 ◽  
Vol 3 (1) ◽  
pp. 22
Author(s):  
Deswati ◽  
Hamzar Suryani ◽  
Imelda ◽  
Yulia

 ABSTRACT Study of optimation chromium (VI) in sea water by adsorptive stripping voltammetry has been done. The aim of this method to get optimum conditions for determination of Cr(VI). Adsorptive stripping voltammetry (AdSV) has been used for the ultra trace determination of chromium using 2,2’- bipyridin as ligand. Parameters were done, like accumulation time, concentration of ligand, pH, accumulation potential, electrolyte concentration and catalyst concentration. In this case, the optimum conditions were reached in accumulation time 80 second, pH 5.0, concentration of 2,2’- bipyridin 10 μM, accumulation potential -0,6 Volt and electrolyte concentration (NH4Cl) 0,1 M. In the optimum conditions, a linear calibration graph was obtained with correlation coefficient of 0.9971, the relative standard deviation was 15.06 % for eight replicates (n = 8) measurements of 10 μg/L of Cr(VI). The detection limit method was 0.1692 μg/L. The method was applied to the direct determination of Cr(VI) in sea water around Muara Padang water. Concentration Cr(VI) in sample was equal to 0.9684 μg/L with recovery of 90.23 %. Keywords : optimation, chromium, adsorptive, stripping, voltammetry


2013 ◽  
Vol 13 (3) ◽  
pp. 236-241 ◽  
Author(s):  
Deswati Deswati ◽  
Hamzar Suyani ◽  
Safni Safni ◽  
Umiati Loekman ◽  
Hilfi Pardi

A selective and sensitive adsorptive stripping voltammetric (AdSV) procedure for the simultaneous determination of cadmium, copper and lead in the sea water was conducted. The aim of this research is to get optimum condition for simultaneous determination of cadmium, copper and lead. Adsorptive stripping voltammetry has been used for determination of trace amount of Cd(II), Cu(II) and Pb (II) by using calcon as a complexing agent. The parameters studied were variation of calcon concentration, pH, accumulation potential and accumulation time. In this study, the optimum conditions were calcon concentration of 0.6 mM, pH = 4.0, accumulation potential of -0.7 V and accumulation time of 80 sec. At the optimum conditions, the relative standard deviation were 8.78%, 3.12%, and 4.02% for Cd(II), Cu(II) and Pb(II) respectively for eight replicates (n = 8) measurements of 10 μg/L mixed standard solution of Cd(II), Cu(II) and Pb(II). The method was applied to the direct simultaneous determination of Cd(II), Cu(II) and Pb(II) in sea water around Bungus, Padang City. Concentration of Cd(II), Cu(II) and Pb(II) in samples were equal to 1.8 μg/L for Cd(II), 38.6 μg/L for Cu(II) and 0.7 μg/L for Pb(II) with recovery of 87.03%, 98.80%, and 95.73%, respectively.


2015 ◽  
Vol 3 (2) ◽  
pp. 122
Author(s):  
Deswati Deswati ◽  
Hamzar Suyani ◽  
Citra Buhatika

  ABSTRACT Study of optimation cadmium(II) by adsorptive stripping voltammetry has been done. The aim of this study to get optimum conditions for determination of Cd(II). Parameters were done : potential accumulation, time accumulation, pH, supporting electrolite concentration and optimum of complex concentration. In this case, the optimum conditions were reached in potential accumulation -0.7 V, time accumulation 60 second, pH 7.0, NH4Cl 0.12 M, calcon concentration 0.12 mM. In the optimum condition was obtained with the relative standard deviation was 4.61% for eight replicates, measurements of 0.01 ppm. The method was applied to the direct determination of Cd(II) in water around Batang Air Dingin Lubuk Minturun and Muara Padang. Concentration Cd(II) in sample was equal to 7.359 μg/L and 3.659 μg/L with recovery of 99.04%. Keywords: cadmiun, adsorptive, stripping, voltammetry


2014 ◽  
Vol 2 (6) ◽  
pp. 691-700 ◽  
Author(s):  
Tarik Attar ◽  
Yahia Harek ◽  
Lahcene Larabi

 A selective and sensitive method for determination of copper in blood by adsorptive differential pulse cathodic stripping voltammetry is presented. The method is based on adsorptive accumulation of the complexes of Cu (II) ions with benzenesulfonyl hydrazide onto hanging mercury drop electrode (HMDE), followed by the reduction of the adsorbed species by differential pulse cathodic stripping voltammetry. The effect of various parameters such as supporting electrolyte, concentration of benzenesulfonyl hydrazide, accumulation potential, accumulation time and stirring rate on the selectivity and sensitivity were studied. The optimum conditions for determination of copper include perchloric acid 0.03 M, concentration of benzenesulfonyl hydrazide 7.5×10-5 M, the accumulation potential of -350 mV (vs. Ag/AgCl), the accumulation time of 50 s, and the scan rate of 50 mV s-1. Under optimized conditions, linear calibration curves were established for the concentration of Cu (II) in the range of 0.62-275 ng mL-1, with detection limit of 0.186 ng mL-1 for Cu (II). The procedure was successfully applied to the determination of copper ion in whole blood samples.


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