Monitoring of praseodymium(III) ions in aqueous solutions, soil and sediment samples by a PVC membrane sensor based on a furan-triazole derivative

A furan-triazole derivative has been explored as an ionophore for preparation of a highly selective Pr(III) membrane sensor. The proposed sensor exhibits a Nernstian response for Pr(III) activity over a wide concentration range with a detection limit of 5.2×10-8 M. Its response is independent of pH of the solution in the range 3.0-8.8 and offers the advantages of fast response time. To investigate the analytical applicability of the sensor, it was applied successfully as an indicator electrode in potentiometric titration of Pr(III) solution and also in the direct and indirect determination of trace Pr(III) ions in some samples

Preparation of a Modified Octadecyl Silica Membrane Disk for Solid Phase Extraction of Lead(II) Ions in Different Real Samples and their Determination with ICP-AES

A solid phase extraction and inductively coupled plasma atomic emission spectrometry (ICP-AES) for the determination of lead(II) ions with octadecyl-bonded silica membrane disks modified by 4-methyl-N-{2-(4-methylbenzothioyl)aminoethyl}benzenecarbothioamide (MMAB) was studied. Extraction efficiency, and the effects of parameters such as flow rate, pH, type and the least amount of acid for stripping of lead(II) from the modified disks andbreak through volume were examined. The maximum capacity of the membrane disks modified by 4.0 mg of MMAB used was found to be 527 ± 4 µg of lead(II) ions. The preconcentration factor is 440 (for 2200 mL water sample and flow rate of 12 mL min-1) and detection limit of the proposed method is 85.4 ng mL-1. The developed method was successfully applied to the determination of lead(II) ions in blood, spinach, bean, hair, milk, pepper and various water samples

Supramolecular based membrane sensors

Abstract: Supramolecular chemistry can be defined as a field of chemistry, which studies the complex multi-molecular species formed from molecular components that have relatively simpler structures. This field has been subject to extensive research over the past four decades. This review discusses classification of supramolecules and their application in design and construction of ion selective sensors

Ultra-trace monitoring of copper in environmental and biological samples by inductively coupled plasma atomic emission spectrometry after separation and preconcentration by using octadecyl silica membrane disks modified by a new schiff's base

Ultra-trace amounts of Cu(II) were separated and preconcentrated by solid phase extraction on octadecyl-bonded silica membrane disks modified with a new Schiff,s base (Bis- (2-Hydroxyacetophenone) -2,2-dimethyl-1,3-propanediimine) (SBTD) followed by elution and inductively coupled plasma atomic emission spectrometric detection. The method was applied as a separation and detection method for copper(II) in environmental and biological samples. Extraction efficiency and the influence of sample matrix, flow rate, pH, and type and minimum amount of stripping acid were investigated. The concentration factor and detection limit of the proposed method are 500 and 12.5 pg mL-1, respectively

Evaluation of the Slope of Amplitude Growth Function Changes of the Electrically Evoked Action Potential in Three Months after Receiving the Device in Children with Cochlear Implant

Objective: In neural response telemetry, intracochlear electrodes stimulate the auditory nerve and record the neural responses. The electrical stimulation is sent to the auditory nerve by an electrode and the resulted response, called electrically evoked compound action potential, is recorded by an adjacent electrode. The most important clinical applications of this test are evaluation and monitoring the intra and postoperative responses of auditory nerve and help to primary setting of speech processor. The aim of this study was evaluating the potential's slope of amplitude growth function changes three monthes after receiving the devise in pediatric cochlear implant recipients. Materials & Methods: This longitudinal study evaluated the potentials' slope of amplitude growth function changes in four given electrodes in four sessions after receiving the devise by approximately one month's intervals in all of the children who implanted in Amir Alam and Hazrat-e-Rasoul hospitals in 2007, July to December. Friedman test was used to analyse the results. Results: Electrically evoked compound action potential's mean slope of each electrode was more in later sessions relative to first session, while there was significant difference between the 1st and the other electrodes’ responses in every session (P<0.05). Conclusion: The reliabiliy of the responses results in more assurance of clinician to fit the speech processor for along time. Better responses in apical electrodes may lead to develope an effective coding strategy