Method For Determination Of Iodide Research Articles

Electrocatalytic response of chitosan modified multiwall carbon nanotube paste electrode toward iodide: A facile voltammetric method for determination of iodide in biological sample

Herein we report, a simple operable, sensitive, and highly selective, voltammetric method for the determination of iodide (Iˉ) using chitosan modified multiwall carbon nanotube paste electrode (chit-MWCNTPE). It is established that chit-MWCNTPE exhibited a pronounced response toward Iˉ oxidation. The peak potential of Iˉ is recorded at 0.69 V vs SCE. The conditions such as scan rate (V.s−1), accumulation time (ta), and pH are thoroughly optimized for the voltammetric determination of Iˉ. A wide range linear response is observed between oxidation peak current and Iˉ concentration (0.1–100 μM). The limit of detection (LOD) for Iˉ on chit-MWCNTPE is found to be 0.03 μM. The developed method is highly selective for Iˉ detection in the presence of various interfering ions. The method is successfully applied for the determination of Iˉ in urine samples. The method has high selectivity for Iˉ detection at comparably low potential as well as amiable LOD and Linear range.

Determination of iodide and total iodine in estuarine waters by cathodic stripping voltammetry using a vibrating silver amalgam microwire electrode

Iodide in natural waters is an important nutrient to aquatic organisms and its determination is of relevance to marine aquaculture. For this reason it is of interest to have a simple analytical method for determination of iodide in water samples. Iodide in seawater can be determined electrochemically by cathodic stripping voltammetry (CSV) with a mercury drop electrode which has environmental drawbacks. In an attempt to minimise the use of mercury in voltammetry, a vibrating silver amalgam microwire electrode is used here for the determination by CSV of iodide speciation in natural waters including seawater. Microwire electrodes were made from silver wires (diameter: 12.5µm) and electrochemically coated with mercury. The electrode surface was stable for extended periods of analyses (at least one week) and was then replaced. The optimised conditions include a pH 8, a frequency of 500Hz and a deposition time of 60s, among others. The microwire was reactivated between scans using a conditioning potential at −3 V for 1s. The detection limit for iodide in seawater was found to be 0.7nM I- at a deposition time of 60s. The response increased linearly with the concentration of iodide in seawater up to 100nM I-. The method was successfully applied to various samples from the estuary of the river Mersey (Liverpool Bay). An existing procedure for iodine speciation was modified to enable determination of iodate and total iodine as well as iodide in estuarine waters.

Determination of Inorganic Anions by Capillary IC Using Hexadimethrine Bromide-Modified Silica Stationary Phases

A simple, rapid and highly sensitive capillary ion chromatographic method for direct determination of iodide and thiocyanate is reported. Separation was achieved on a laboratory-made capillary column (100 mm × 0.32 mm i.d.) packed with silica gel, followed by modification with 20 mM hexadimethrine bromide. Sodium perchlorate–methanol (95:5, v/v) was used as the eluent and analyte anions were detected at 225 nm. Iodate, bromate, nitrate, iodide and thiocyanate were eluted within 8 min, with relative standard deviations of the retention time, peak area and peak height smaller than 2.4%. Effects of the eluent composition on the retention behavior were also investigated. The limit of detection (S/N = 3) of iodide was 6.5 μg L−1, whereas that of thiocyanate was 16.2 μg L−1. The method was successfully applied to the rapid and direct determination of iodide in powdered milk and thiocyanate in human saliva without any pre-concentration. The modified column could be used for about 1 month (8 h operation per day) without loss of hexadimethrine bromide.

A Simple and Selective Flow-Injection Potentiometric Method for Determination of Iodide Based on a Coated Glassy Carbon Electrode Sensor

A Simple and Selective Flow-Injection Potentiometric Method for Determination of Iodide Based on a Coated Glassy Carbon Electrode Sensor

Fast and simple method for determination of iodide in human urine, serum, sea water, and cooking salt by capillary zone electrophoresis.

For the determination of iodide in urine, where 80-90% of consumed iodine is excreted, a fast, simple, and sensitive method of capillary zone electrophoresis was elaborated and tested also for additional complex matrices such as human serum, cooking salt, and seawater. Several approaches were examined for the separation of iodide from other macro- and microcomponents in the tested matrices, and the best results were obtained when host-guest interaction with alpha-cyclodextrin or ion-pairing with polyethylenimine was employed. In both cases comparable resolution and sensitivity were reached. Due to the relatively high price of cyclodextrin only the method with polyethylenimine was further optimized and a simple procedure enabling the determination of iodide in untreated human urine, serum, cooking salt, and seawater was elaborated. The samples were injected for 20 s at 0.5 psi (3.45 kPa) into a fused-silica capillary (0.18 mm ID, 50 cm effective length) coated with polyacrylamide (electroosmotic flow < 2 x 10(-9) m(2)V(-1)s(-1)) and filled with the optimized background electrolyte composed of 20 mM KH(2)PO(4) and 0.7% m/v polyethylenimine. For detection, UV absorption at 200 and 230 nm was measured. Concentration limits of detection reached at 230 nm were for human urine 0.14 microM, for human serum 0.17 microM, for seawater 0.17 microM, and for cooking salt 89 nM. Relative standard deviations of iodide peak area and height in all matrices ranged within 0.93 to 4.19%.

Simple and selective method for determination of iodide in pharmaceutical products by flow injection analysis using the iodine-starch reaction.

This work exploited the well-known iodine-starch reaction for development of a simple flow-injection (FI) method for determination of iodide in pharmaceutical samples. Iodide in an injected zone was oxidized to iodine. A gas diffusion unit enables selective permeation of iodine through a hydrophobic membrane. Detection was made very selective for elemental iodine by employing formation of the I(3)(-)-starch complex. The detection limit (3 S/ N) of the system was 1 mg I L(-1). For a liquid patent medicine used for asthma treatment we suggested modification of the system. Direct injection of this sample, which contains a particularly high concentration level of iodide (ca. 9000 mg I L(-1)), can be achieved by coupling a dialysis unit to the FI system. This has increased the working range to 6000-10,000 mg I L(-1) without employing complicated nanoliter injection.

A Radiometric Method for Determination of Iodide in Natural Waters.

A Radiometric Method for Determination of Iodide in Natural Waters.