Perchlorate-selective membrane electrode based on a new complex of uranil

Perchlorate Solid-Contact Ion-Selective Electrode Based on Dodecabenzylbambus[6]uril

Dodecabenzylbambus[6]uril (Bn12BU[6]) is an anion receptor that binds the perchlorate ion the most tightly (stability constant ~1010 M−1) of all anions due to the excellent match between the ion size in relation to the receptor cavity. This new bambusuril compound was used as an ionophore in the ion-selective membrane (ISM) to develop ion selective electrodes (ISEs) for determination of perchlorate concentration utilizing the poly(3,4-ethylenedioxythiophene) (PEDOT) polymer film as a solid-contact material. Variation of the content of Bn12BU[6] and tridodecylmethylammonium chloride (TDMACl) in the plasticized poly(vinyl chloride)-based ISM was also tested. All the prepared solid-contact ISEs and their analytical performance were characterized by potentiometry, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronopotentiometry. The ISEs showed rapid response and a sub-Nernstian slope (~57 mV/decade) during potentiometric measurements in perchlorate solutions in the concentration range from 10−1 to 10−6 M simultaneously with their high stability and sufficient selectivity to other common inorganic anions like bromide, chloride, nitrate and sulphate. The function of the ISE was further verified by analysis of real water samples (lake, sea, and mineral water), which gave accurate and precise results.

Perchlorate occurrence in foodstuffs and water: Analytical methods and techniques for removal from water - A review

Perchlorate (ClO₄^-), a type of contaminant with high diffusivity and durability, has been widely detected in water and foodstuffs, arousing a global concern. It can interfere with normal function of the human thyroid gland, affecting human health. Therefore, determination of perchlorate in water and foodstuffs, and removal from water are important. This review focuses on the occurrence of perchlorate, mainly in water and foodstuffs, and provides an overview of analytical methods for determination of perchlorate over the last two decades. In addition, merits and drawbacks of the various methods have been considered. This review also highlights the most commonly used approaches for removal of perchlorate from water. Finally, current trends and future perspectives in determination of perchlorate and removal from water are proposed. This review provided a comprehensive understanding of perchlorate occurrence and its removal from water, and had practical significance in reducing the harm of perchlorate to human.

Luminescence sensing of weakly-hydrated anions in aqueous solution by self-assembled europium(iii) complexes

Perchlorate anions in water could be sensed by luminescence decrease of europium(iii) using a self-assembly system.

Perchlorate-selective polymeric membrane electrode based on bis(dibenzoylmethanato)cobalt(II) complex as a neutral carrier

A synthesized bis(dibenzoylmethanato)Co(II) complex (Co(DBM)(2)), has been used as a ionophore for the preparation of a new perchlorate ion-selective electrode. The electrode exhibits a Nernstian response over the perchlorate concentration range of 8.0x10(-7)-1.0x10(-1)M with a slope of 60.3+/-0.5 mV per decade of concentration. The limit of detection as determined from the intersection of the extrapolated linear segments of the calibration plot is 5.6x10(-7)M. The electrode shows good selectivity towards perchlorate with respect to many common anions. The response time of the sensor is very fast (< or = 5s), and can be used for at least 2 months in the pH range of 2.0-9.0. The electrode was used to determine perchlorate in water and human urine. The interaction of the ionophore with perchlorate ions was demonstrated by UV-vis spectroscopy.

Developments in the Field of Conducting and Non-conducting Polymer Based Potentiometric Membrane Sensors for Ions Over the Past Decade

Many research studies have been conducted on the use of conjugated polymers in the construction of chemical sensors including potentiometric, conductometric and amperometric sensors or biosensors over the last decade. The induction of conductivity on conjugated polymers by treating them with suitable oxidizing agents won Heeger, MacDiarmid and Shirakawa the 2000 Nobel Prize in Chemistry. Common conjugated polymers are poly(acetylene)s, poly(pyrrole)s, poly(thiophene)s, poly(terthiophene)s, poly(aniline)s, poly(fluorine)s, poly(3-alkylthiophene)s, polytetrathiafulvalenes, polynapthalenes, poly(p-phenylene sulfide), poly(p-phenylenevinylene)s, poly(3,4-ethylenedioxythiophene), polyparaphenylene, polyazulene, polyparaphenylene sulfide, polycarbazole and polydiaminonaphthalene. More than 60 sensors for inorganic cations and anions with different characteristics based on conducting polymers have been reported. There have also been reports on the application of non-conducting polymers (nCPs), i.e. PVC, in the construction of potentiometric membrane sensors for determination of more than 60 inorganic cations and anions. However, the leakage of ionophores from the membranes based on these polymers leads to relatively lower life times. In this article, we try to give an overview of Solid-Contact ISE (SCISE), Single-Piece ISE (SPISE), Conducting Polymer (CP)-Based, and also non-conducting polymer PVC-based ISEs for various ions which their difference is in the way of the polymer used with selective membrane. In SCISEs and SPISEs, the plasticized PVC containing the ionophore and ionic additives govern the selectivity behavior of the electrode and the conducting polymer is responsible of ion-to-electron transducer. However, in CPISEs, the conducting polymer layer is doped with a suitable ionophore which enhances the ion selectivity of the CP while its redox response has to be suppressed.

Matrix interference free determination of perchlorate in urine by ion association–ion chromatography–mass spectrometry

Quantitative measurement of perchlorate in biological fluids is of importance to assess its toxicity and to study its effects on the thyroid gland. Whenever possible, urine samples are preferred in toxicologic/epidemiologic studies because sample collection is non-invasive. We present here a pretreatment method for the determination of perchlorate in urine samples that lead to a clean matrix. Urine samples, spiked with isotopically labeled perchlorate, are exposed to UV to destroy/decompose organic molecules and then sequentially treated with an H+-form cation exchange resin to remove protolyzable compounds, with ammonia to raise the pH to 10-11 and finally passed through a mini-column of basic alumina to remove the color and other organic matter. After filtration through a 0.45 microm syringe filter, the sample thus prepared can be directly injected into an ion chromatograph (IC). We use ion association-electrospray ionization-mass spectrometry (ESI-MS) to detect and quantify perchlorate. The proposed sample preparation method leads to excellent limits of detection (LOD's) for perchlorate since there is essentially no dilution of sample and the matrix effects are eliminated. Results of urine samples from both men and women volunteers are reported for perchlorate, as well as for iodide and thiocyanate, which are generally present at much higher concentrations and for which a "dilute and shoot" approach is adequate. The limit of detection (S/N=3) for iodide, thiocyanate and perchlorate by the present method was 0.40, 0.10 and 0.080 microg l(-1), respectively.