Analysts anions

Active matter (anionic surfactant) in AOS consists of alkene- and hydroxy-alkanemonosulfonates, as well as small amounts of disulfonates. Active matter (AM) content is usually expressed as milliequivalents per 100 grams, or as weight percent. Three methods are available for the determination of AM in AOS calculation by difference, the two-phase titration such as methylene blue-active substances (MBAS) and by potentiometric titration with cationic. The calculation method has a number of inherent error factors. The two-phase titration methods may not be completely quantitative and can yield values differing by several percent from those obtained from the total sulfur content. These methods employ trichloromethane, the effects from which the analyst must be protected. The best method for routine use is probably the potentiometric titration method but this requires the availability of more expensive equipment. 

Hu, W. Z., Haddad, P. R., Tanakar, K., and Hasebe, K., Modulation of the separation selectivity of inorganic anions in electrostatic ion chromatography using acidic eluents, Analyst, 125, 241, 2000. 

CE has been used for the analysis of anionic surfactants [946,947] and can be considered as complementary to HPLC for the analysis of cationic surfactants with advantages of minimal solvent consumption, higher efficiency, easy cleaning and inexpensive replacement of columns and the ability of fast method development by changing the electrolyte composition. Also the separation of polystyrene sulfonates with polymeric additives by CE has been reported [948]. Moreover, CE has also been used for the analysis of polymeric water treatment additives, such as acrylic acid copolymer flocculants, phosphonates, low-MW acids and inorganic anions. The technique provides for analyst time-savings and has lower detection limits and improved quantification for determination of anionic polymers, compared to HPLC. 

Westergaard B, Hansen HBC, Borggaard OK. Determination of anions in soil solutions by capillary zone electrophoresis. Analyst 1998 123 721-742. 

Surfactants are surface-active compounds, which are used in industrial processes as well as in trade and household products. They have one of the highest production rates of all organic chemicals. Commercial mixtures of surfactants consist of several tens to hundreds of homologues, oligomers and isomers of anionic, non-ionic, cationic and amphoteric compounds. Therefore, their identification and quantification in the environment is complicated and cumbersome. Detection, identification and quantification of these compounds in aqueous solutions, even in the form of matrix-free standards, still poses the analyst considerable problems. 

Numerous applications have been shown to exist that overcome the general problems of lack of volatility and instability at higher temperatures that principally hamper direct analysis of surfactants by GC methods. Thus, a whole suite of derivatisation techniques are available for the gas chromatographist to successfully determine anionic, non-ionic and cationic surfactants in the environment. This enables the analyst to combine the high-resolution chromatography that capillary GC offers with sophisticated detection methods such as mass spectrometry. In particular, for the further elucidation of the complex mixtures, which is typical for the composition of many of the commercial surfactant formulations, the high resolving power of GC will be necessary. 

Figure 5.5 Scheme illustrating potential reorientation of bonded imidazolium ligands in response to deprotonation of residual silanols. Anion is not shown for clarity. (Adapted from Wang, Q., Baker, G. A., Baker, S. N., and Colon, L. A., Analyst, 131,1000-1005, 2006.)... 

Wu, J., Yu, X., Lord, H., and Pawliszyn, J., Solid phase microextraction of inorganic anions based on polypyrrole film. Analyst, 125, 391-394, 2000. 

The first edition of Food Analysis by HPLC fulfilled a need because no other book was available on all major topics of food compounds for the food analyst or engineer. In this second edition, completely revised chapters on amino acids, peptides, proteins, lipids, carbohydrates, vitamins, organic acids, organic bases, toxins, additives, antibacterials, pesticide residues, brewery products, nitrosamines, and anions and cations contain the most recent information on sample cleanup, derivatization, separation, and detection. New chapters have been added on alcohols, phenolic compounds, pigments, and residues of growth promoters. 

Ding, M., Tanaka, K., Hu, W., Hasebe, K., and Haddad, P. R. (2001) Simultaneous Ion-exclusion Chromatography and Cation-exchange Chromatography of Anions and Cations in Environmental Water Samples on a Weakly Acidic Cation-exchange Resin by Elution with Pyridine-2,6-dicarboxylic Acid, Analyst 126, 567-570. 

J. H. Zou, S. Motomizu, and H. Fukutomi, Reversed-phase ion-interaction chromatorgaphy of inorganic anions with tetraalkylam-monium ions and divalent organic anions using indirect photometric detection, Analyst, 776 1399 (1991). 

Takayanagi, T., Wada, E., and Motomizu, S. Electrophoretic mobility study of ion association between aromatic anions and quaternary ammonium ions in aqueous solution. Analyst 1997, 122, 57-62. 

Hatsis, P. and Lucy, C.A. Ultra-fast HPLC separation of common anions using a monolithic stationary phase. Analyst 2002, 127, 451-454. 

Brunfelt, A. O., Steinnes, E. Determination of lutetium, ytterbium and terbium in rocks by neutron activation and mixed solvent anion-exchange chromatography. Analyst 94, 979 (1969)... 

Franks, M. C., Pullen, D. L. Technique for the determination of trace anions by the combination of a potentiometric sensor and liquid-chromatography with particular reference to the determination of halides. Analyst 99, 503 (1974)... 

Zheng, B., Hinlelmann, H. Hyphenation of high performance liquid chromatography with sector field inductively coupled plasma mass spectrometry for the determination of ultra-trace level anionic and cationic arsenic compounds in freshwater fish. J Anal At Spectrom 2004,19, 191-195. Pergantis, S. A., Heithmar, E. M., Hinners, T. A. Speciation of arsenic animal feed additives by microbore high-performance liquid chromatography with inductively coupled plasma mass spectrometry. Analyst 1997, 122, 1063-1068. 

C.-H. Wu, L. Scampavia, J. Ruzicka, Microsequential injection anion separations using Lab-on-Valve coupled with capillary electrophoresis, Analyst 127 (2002) 898. 

M. Agudo, A. Rios, M. Valcarcel, Continuous liquid—liquid extraction with on-line monitoring for the determination of anionic surfactants in waters, Analyst 119 (1994) 2097. 

S. Motomizu, M. Onoda, M. Oshima, T. Iwachido, Spectrophotometric determination of potassium in river water based on solvent extraction of the complex formed with a crown ether and an anionic azo dye using flow injection, Analyst 113 (1988) 743. 

Bradfield, E. G. and Cooke, D. T., Determination of inorganic anions in water extracts of plants and soils by ion chromatography. Analyst, 110, 1409-1410, 1985. 

Cheam, V. and Chau, S. Y., Automated simultaneous analysis of anions and monovalent and divalent caAons, Analyst, 112, 993-997, 1987. 

A. J. Frend, G. J. Moody, J. D. R. Thomas, and B. J. Birch, Flow Injection Analysis with Tubular Membrane Ion-Selective Electrodes in the Presence of Anionic Surfactants. Analyst, 108 (1983) 1357. 

A. Rios, M. D. Luque de Castro, and M. Valcarcel, New Approach to the Simultaneous Determination of Pollutants in Waste Waters by Flow Injection Analysis. Part I. Anionic Pollutants. Analyst, 109 (1984) 1487. 

Garcia-Vargas, M., Milla, M. and Perez-Bustamante, J.A. (1983). Atomic Absorption Spectroscopy as a Tool for the Determination of Inorganic Anions and Organic Compounds. Analyst. 108, 1417. 

In principle, any ion which can be oxidized or reduced or which will form a stable complex or slightly soluble salt with mercury can be determined polarographically. A survey of the literature indicates that the polarographic behavior of some 80 elements has been described and analytical determinations of most of these have been accomplished. Accordingly, polarography should be useful for determining most of the cations and indeed a number of anions of interest to water analysts. 

ICP-MS offers sensitivity, accuracy, and precision with multi-element capabilities, which is not available with other analytical techniques. The unique qualities of ICP-MS, when coupled with proper chromatographic techniques, provides the analyst with concentration and nature of the elemental species present in their samples. Other elemental techniques, which have been coupled with chromatographic systems, do not exhibit the same robustness as has been demonstrated with the ICP-MS [4,5]. Exploiting this ability, we were able to use ICP-MS coupled with an anionic chromatography separation, to determine ideal conditions for remediation of selenium contamination in various aqueous refinery streams. 

The alternative instrumental assay methods. X-ray fluorescence, atomic spectroscopy and thermotitrimetry, will be compared with the classical methods for precision and ease of measurement. Instrumental methods have greatly extended the ability of the analyst to detect trace cations and anions in soluble silicates. 

Detection of the molecules produced, consumed, and secreted by the cells described here is challenging for two main reasons. First, the cell is dynamic and constantly tries to maintain balance. As such, molecules concentrations or speciation are usually changing. Second, the matrix in which these measurements are typically performed is very complex. Thus, the technique of choice needs to have some built-in feature that enables the analyst to overcome the matrix. To date, a variety of measurements have been employed to learn more about the roles of the cells in the microcirculation. Specifically, fluorescence, chemiluminescence, and amperometry have all been used extensively. Not surprisingly, all three of these detection schemes are readily employed in capillary electrophoresis-based determinations. Therefore, many of the measurements employ technology from the CE field. However, due to the cell matrix complexity, techniques are required to overcome potential interfer-ents. Eor example, Kovarik et al. employed a Nafion coating over a micromolded ink electrode for selectivity in detecting dopamine in the presence of an anion interferent (ascorbate). Eor similar reasons, Ku" ° employed the classic method of multiple standard additions to quantitatively determine the amount of NO released from activated platelets in a flowing stream. 

M.A. Woodland and C.A. Lucy, Altering the selectivity of inorganic anion separations using electrostatic capillary electrophoresis. Analyst, 126, 28—32, 2001. 

F.G.P. Mullins and G.F. Kirkbright, Determination of Inorganic Anions by HPLC using a Micellar Mobile Phase, Analyst, 109 1217 (1984). 

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