Universal Anion

Parameter Metrosep anion dual 2 TSK-Gel IC-PW Shimpack IC-Al Polyspher ICAN-1 Universal anion... 

Soap was considered and used as the universal anionic surfactant in both home-laundry and personal-care detergents till the 1940s. 

The Star Ion A300 IC Anion from Phenomenex (Torrance, CA, USA) is a universal anion exchanger with relatively short analysis times for standard anions when using a carbonate/bicarbonate eluent and suppressed conductivity detection... 

Over the past 5 years, Metrohm (Herisau, Switzerland) also developed a number of surface-aminated PS/DVB-based resins. Metrosep A Supp 1 is a medium-capacity universal anion exchanger with a special selectivity in that bromide elutes behind nitrate. It is predominantly used both for anion analysis in samples with large concentration differences and for separating oxyhalide ions such as bromate, chlorite, and chlorate. 

Metrosep A Supp 15 is a mediuni Capacity universal anion exchanger designed for high mechanical and chemical stability. Therefore, this separator column can be used for standard applications as well as for highly complex separation problems. It exhibits a special selectivity to separate glycolate, formate, and acetate to baseline under isocratic conditions being illustrated in Figure 3.10. 

Carbonate/Bicarbonate-Selective Grafted Polymers The most common surface-functionalized, carbonate/bicarbonate-selective grafted polymer is available under the trade name Dionex lonPac AS14. This universal anion exchanger for the analysis of inorganic anions was developed as an advanced successor product of the nanobead-agglomerated lonPac AS12A [23] (see Section 3.4.1.4). 

The macroporous anion exchanger based on hydroxyethylmethacrylate from AUtech (Deerfield, IL, USA), which was known under the trade name Universal Anion [28,29], is no longer available and has been replaced by Allsep Anion... 

Quitasol and Krastins [504] used a polyhydroxyethylmethacrylate (Universal Anion, Grace Alltech, USA) as a stationary phase 5 mmol/L potassium nitrate adjusted to pH 3.5 with nitric acid serving as an eluent. Under these chromatographic conditions, the organic phosphate can be separated to baseline from orthophosphate and orthophosphite within 10 min. Because Quitasol and Krastins determined only the drug component in various pharmaceutical formulations, they used a refractive index detector for the sake of simplicity. This procedure can be validated in terms of precision, accuracy, and linearity without any difficulties. 

Fig. 3 -19. Separation of various inorganic anions on Alltech Universal Anion. - Separator 150 mm X 4.6 mm i. d. Universal Anion eluant 5 mmol/L p-hydroxybenzoic acid, pH 7.9 with LiOH flow rate 1 mL/min detection direct conductivity injection volume 100 pL solute concentrations 10 mg/L fluoride (1),...

When it was introduced, the lonPac AS12A was clearly the most modem latexed anion exchanger for the separation of fluoride, oxyhalides, and mineral acids. The latest development in the field of universal anion exchangers for water analysis is the lonPac ASM discussed in Section 3.4.1, which is based on a support material with a covalently bonded ion-exchange polymer (see Fig. 3-33 in Section 3.4.1). 

By using an anionic collector and external reflux in a combined (enriching and stripping) column of 3.8-cm (1.5-in) diameter with a feed rate of 1.63 ni/n [40 gal/(h ft )] based on column cross section, D/F was reduced to 0.00027 with C JCp for Sr below 0.001 [Shou-feld and Kibbey, Nucl. AppL, 3, 353 (1967)]. Reports of the adsubble separation of 29 heavy metals, radioactive and otheiwise, have been tabulated [Lemlich, The Adsorptive Bubble Separation Techniques, in Sabadell (ed.), Froc. Conf. Traces Heavy Met. Water, 211-223, Princeton University, 1973, EPA 902/9-74-001, U.S. EPA, Reg. 11, 1974). Some separation of N from by foam fractionation has been reported [Hitchcock, Ph.D. dissertation. University of Missouri, RoUa, 1982]. 

Professor D Auria (Basilicata University) summarizes the photochemical isomerization of pentaatomic heterocycles, providing a unified description in terms of the five conceivable mechanisms. R. Alan Aitken and Andrew W. Thomas of the University of St. Andrews, Scotland, summarize the substantial recent progress in heterocyclic acyl and formyl anion equivalents. 

Sodium dodecyl sulfate is the universal analytical standard for the determination of anionic and cationic active matter. It is used to determine the analytical concentration factor of the cationic surfactant in the titration of anionic active matter and as titrant to determine the cationic active matter. 

The method developed by Epton [212,213] became the universally accepted method for the analysis of active matter of anionic and cationic surfactants. Epton s method, also known as the two-phase titration, is based on the titration of the anionic surfactant with cetylpyridinium bromide, a cationic surfactant, in the presence of methylene blue as indicator. A solution of the anionic surfactant is mixed with the indicator dissolved in dilute sulfuric acid, followed by further addition of chloroform, and then it is titrated with the cationic surfactant. Methylene blue forms a complex with the anionic salt that is soluble in chloroform, giving the layer a blue color. As the titration proceeds there is a slow transference of color to the water layer until the equivalence point. At the equivalence point colors of the chloroform and water layers are visually the same. On successive additions of titrant the chloroform layer lightens in shade and finally becomes colorless. 

Metal nanotube membranes with electrochemically suitable ion-transport selectivity, which can be reversibly switched between cation-permeable and anion-permselective states, have been reported. These membranes can be viewed as universal ion-exchange membranes. Gold nanotube molecular filtration membranes have been made for the separation of small molecules (< 400 Da) on the basis of molecular size, eg. separation of pyridine from quinine (Jirage and Martin, 1999). 

Sjogren. A. and Dasgupta, P. K., Two-dimensional conductimetric detection in ion chromatography. Analyte identification, quantitation of very weak acid anions, and universal calibration, Anal. Chem., 67, 2110, 1995. 

Crompton [21] has reviewed the use of electrochemical methods in the determination of phenolic and amine antioxidants, organic peroxides, organotin heat stabilisers, metallic stearates and some inorganic anions (such as bromide, iodide and thiocyanate) in the 1950s/1960s (Table 8.75). The electrochemical detector is generally operated in tandem with a universal, nonselective detector, so that a more general sample analysis can be obtained than is possible with the electrochemical detector alone. 

The nonmetals are poor conductors of electricity and heat, and their surfaces generally are dull. Their atoms tend to acquire one or more electrons and become negatively charged ions, known as anions. Cations and anions combine with each other, forming the myriad of compounds that make up most of the universe. 

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