Inductively coupled plasma mass spectrometry (ICP/MS) is utilized as a detector for several organotin species separated by high-performance liquid chromatography. Detection limits obtained by ICP/MS are 3 orders of magnitude lower than those obtained with inductively coupled plasma atomic emission spectrometry (ICP/AES) detection under the same chromatographic conditions. Chromatographic detection limits are higher than conventional solution nebulization for the same compound by a factor of 20. Ion-exchange chromatography yields linear response over 3 orders of magnitude, while ion pair chromatography gives a linear response of only 2 orders of magnitude as a result of poor resolution. The relative standard deviation for the injection of 20 ng of tin compounds is less than 10%.

Helium microwave-induced plasma mass spectrometry has been utilised as an element selective detector for capillary gas chromatography. Several trialkyltin and tetraalkyltin compounds were separated via capillary gas chromatography using a DB-1701 stationary phase. Two different tangential flow torches were evaluated. The major difference between the two torches is the use of a tantalum injector which extends through the microwave cavity and provides a means of introducing the effluent from the capillary column directly into the helium plasma. The optimum signal to noise ratio for the tantalum injector torch was obtained at a microwave power of 70 W with a plasma gas flow-rate of about 3 I min-I. Detection limits obtained with the tantalum injector torch ranged from 0.09 to 0.35 pg of Sn, while those achieved using the standard tangential flow torch ranged from 1 to 4 pg of Sn for the organotin species investigated. The relative standard deviation (RSD) of peak-height reproducibilities ranged from 2.4 to 4.3% for manual injection using the tantalum injector torch for 50 pg of Sn. The manual injection of 1 ng of compound resulted in an RSD of ca. 7% for peak height using the standard tangential flow torch. Linear dynamic ranges were over at least three orders of magnitude,

ABSTRAK Metoda selektif dan sensitif penentuan Cd(II), Cu(II), Pb(II) dan Zn(II) dalam air laut secara voltammetri stripping adsorptif telah dilakukan. Tujuan dari penelitian ini adalah untuk mendapatkan kondisi

This work describes a procedure for the simultaneous determination of cadmium in fruit and vegetable samples using adsorptive stripping voltammetry of complexes with calcon at a hanging mercury drop electrode (HMDE) has been optimized using central composite design (CCD). The selection of the experimental conditions was made using experimental of the influence of several parameters were studied : variations of calcon concentration, pH, accumulation potential and accumulation time. The design experiment was a central composite design with 4 factors/variables, 3 levels and 31 treatment combinations. From analysis of variance, it was decided to accept the second-order model and the independent variable, concluded that a significant effect on the response variable (peak current). Based on data analysis with central composite design, the determination of cadmium obtained optimum conditions were : calcon concentration 0.8435 mM, pH 8.0047, accumulation potential -0.6346 Volt and accumulation time 81.85 seconds with a maximum peak current 61.8146 nA. At the optimum condition were obtained relative standard deviation 0.84%, recovery 98.88%, the linear range up to 110 µg/L, limit of detection 1.009 µg/L and LOQ 3.363 µg/L. The procedure was successfully applied to the determination of cadmium in fruit and vegetable samples without prior treatment.

A selective and sensitive adsorptive stripping voltammetric (AdSV)

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%.

Inductively coupled plasma mass spectrometry has been used as a detector for several organotin compounds which were separated with the use of micellar liquid chromatography. Trimethyltin chloride, triethyltin bromide, and tripropyltin chloride were separated with a 0.1 M sodium dodecyl sulfate (SDS) micellar mobile phase and C-18 stationary phase. Detection limits for the three were 27, 51, and 111 picograms tin, respectively. A 0.02 M SDS mobile phase was used to separate monomethyltin trichloride, dimethyltin dichloride, and trimethyltin chloride. Detection limits for these compounds were 46, 26, and 126 picograms tin, respectively. Preliminary separation of those five organotin compounds was obtained by gradient elution. Calibration curves were linear over 3.5 orders of magnitude. The relative standard deviation for ten 100-μL injections containing 4 ng tin ranged from 1.3 to 1.9% with a 0.1 M SDS mobile phase and from 3.4 to 4.8% with a 0.02 M SDS mobile phase.

No abstract