Ion-exchange chromatographic

Fou, M. F., A split stream ion exchange chromatographic method for isolating amino acids and peptides, Anal. Biochem., 55, 51, 1973. 

Small, H., Stevens, T. S., and Bauman, W. C., Novel ion exchange chromatographic method using conductimetric detection, Anal. Chem., 47, 1801, 1975. 

Vermillion, W. D. and Crenshaw, M. D., In-line respeciation an ion-exchange chromatographic method applied to the separation of degradation products of chemical warfare nerve agents in soil, /. Chromatogr. A, 770, 253, 1997. 

Materials required Autoclave, ion-exchange chromatograph (Murphy and Aarssen 1995a,b,c,d)... 

An ion-exchange chromatographic procedure utilising Dowex 1X2 has been made the basis of an industrial process for manufacturing neomycin B which is free from neomycin C- -9. ... 

Flow through conductance cells are useful detectors in ion-exchange chromatographic separations where the analytes are ionic when they enter the detector cell. At the low concentrations encountered, conductivity is proportional to the mobility of the ions involved as well as their concentration, and this, together with the background conductivity of the solvent, demands that standards are used. Conductivity increases with an increase in temperature and it is important in such measurements that temperature is monitored and appropriate corrections made when calculating the results. 

Both preconcentration and purification are accomplished with traditional ion exchange chromatographic methods. More than one procedure has been used—the interested reader is referred to relevant publications for analytical details (Barling et al. 2001, Siebert et al. 2001). 

High-Performance Ion-Exchange Chromatographic Separation of Peptides... 

Figure 17.2 Ion-exchange chromatographic separation of mixed aqueous lan-thanide(III) ion.

Gas chromatography (GC) for amino acid analysis is the alternative to HPLC that has found the greatest acceptance. It requires the preseparation derivatization of the amino acids to render them volatile. For this purpose, amino acids are frequently converted into acylated esters. N-Trifluoroacetyl-n-butyl esters and /V-heptafluorobutyrylisobutyl esters are most commonly employed. There have been comparative studies (3,4) that document similar (if not equivalent) analytical results for GC and the classic ion-exchange chromatographic method applied to a variety of food samples. Comparison (5) of GC to the reversed-phase HPLC determination of amino acids (phenylisothiocyanate derivatized) also shows excellent agreement. 

JWG Porter, DR Westgarth, AP Williams. A collaborative test of ion-exchange chromatographic methods for determining amino acids. Br J Nutr 22 437-450, 1968. 

Figure 10.1 Ion-exchange chromatographic separation of main anions found in water using a Dionex HPLC and AS-11 HC column. Conditions column Dionex AS-11 HC 250 X 4 mm solvent Milli-Q water and 3 mM NaOH for 6 mins then to 30 mM NaOH over 15 min flow rate 1.5 ml/min suppressed conductivity detection.

Kim and Kim [6] have described an extremely sensitive determination of nitrite in drinking water (tap water and underground water) and environmental samples (rain, lake water, and soil) by ion exclusion chromatography with electrochemical detection. Potential interferences in the determination of nitrite by the standard spectrophotometric method or by the ion exchange chromatographic method with either conductivity or ultraviolet detection were eliminated. The detection limit was 0.1 pg L 1 without preconcentration. 

An ion exchange chromatographic method has been described [16] for the determination of the various forms of vanadium in fresh water. These include tetravalent cationic, pentavalent anionic and neutral complexed forms of vanadium. Separation is achieved on two columns in series involving the absorption of the sample on Chelex 100 and Dowex 1x8 columns followed by the selective elution of the different vanadium species and their assay by neutron activation analysis. Experiments were carried out using vanadium-48... 

Small et al. [20] have discussed a novel ion exchange chromatographic method for the determination of a wide range of elements in surface waters. 

Araki et al. [21] have described an ion exchange chromatographic technique for determining these elements. Detection was by hydrogen flame ionisation. Cerium and phosphate interfere in this method. 

Sherwood and Johnson [33] have described an ion exchange chromatographic determination of nitrate and amperometric detection at a copperised cadmium electrode. The chromatograms obtained in this procedure resolve nitrate from dissolved oxygen. 

Radiochemical Determination of Plutonium in Water by Ion Exchange Chromatographic... 

Hoebregs, H., Fructans in foods and food products, ion-exchange chromatographic method collaborative study, J. Assoc. Off. Anal. Chem. Int., 80, 1029-1037, 1997. 

This influence of the valence and activity coefficients of the displacer salt on the retention behavior of polypeptides and proteins can be anticipated from theoretical treatments of the ion-exchange chromatographic separation of proteins. According to the nonmechanistic stoichiometric model of protein retention behavior in HP-IEX80,82-85 the influence of a divalent cation salt such as CaCl2 on the retention behavior of a protein in HP-IEC can be evaluated in terms of the following relationships ... 

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