Ion-interaction reagent

Gennaro, M. C., Bertolo, P. L., and Marengo, E., Determination of aromatic amines at trace levels by ion interaction reagent reversed-phase high-performance liquid chromatography. Analysis of hair dyes and other water-soluble... 

In particular, the priority pollutant phenols (PPP), identified by EPA since the 1970s are widespread water pollutants that must receive the greatest attention due to their recognized toxicity. For the separation of eleven PPP, an ion-interaction reagent (HR) RP HPLC/UV method has been developed that allows limits of detection lower than 30 J,g in river waters, after LLE in dichlo-romethane and a 500-fold pre-concentration [82]. Through on-line SPE followed by both UV and electrochemical detection [83], 16 priority phenols have been determined in water samples with the LOD value for chlorophenols lower than 1 ng L [84]. LODs at ng L levels were obtained for all the PPPs in samples of river water, employing a relatively small volume of sample through an on-line SPE HPLC/MS method with an APCI source. 

An overview and discussion is given of literature methods published after 1989 devoted to the ion-interaction chromatographic determination of inorganic anions. Seventy references are quoted. Ion-interaction chromatography makes use of commercial reversed-phase stationary phase and conventional high-performance liquid chromatography instrumentation. The basis of the technique, the modification of the stationary phase surface, the choice of the ion-interaction reagent as well as the dependence of retention on the different variables involved are discussed. Examples of application in the fields of environmental, clinical and food chemistry are presented. The experimental conditions of stationary phase, of mobile phase composition as well as detection mode, detection limit and application are also summarized in tables. 1997 Elsevier Science B.V. 

Modification of the reversed-phase stationary phase choice of the ion-interaction reagent detection. 190... 

The mobile phase is an aqueous or hydro-organic solution of a suitable ion-interaction reagent. 

M. C. Gennaro, Separation of water-soluble vitamins by reversed-phase ion-interaction-reagent high-performance liquid chromatography Application to multivitamin pharmaceuticals, J. Chromatogr. Sci., 29 410(1991). 

Figure 5.20 Response surface ( two-dimensional window diagram ) for the separation of a mixture of nine acidic solutes by RPLC. Variables are pH and the concentration of an ion interaction reagent (NOA = n-octylamine). The vertical axis represents the lowest value of a observed for any combination of two solutes in the sample (ffmin). Figure taken from ref. [559J. Reprinted with permission.

Cecchi, T., Pucciarelli, F., and Passamonti, P. Ion interaction chromatography of zwitterions fractional charge approach to model the inflnence of the mobile phase concentration of the ion-interaction reagent. Analyst 2004, 129, 1037-1042. 

Cecchi, T. et al. The fractional charge approach in ion-interaction chromatography of zwitterions influence of the stationary phase concentration of the ion interaction reagent and pH. J. Liq. Chromatogr. Rel. Technol. 2005, 28, 2655-2667. 

Cecchi, T. Pucciarelli, F. Passamonti, P. Ion-Interaction Chromatography of Zwitterions. The Fractional Charge Approach to Model the Influence of the Mobile Phase Concentration of the Ion-Interaction Reagent The Analyst. 2004, 129, 1037-1046. (article B404721D available DOI 10.1039/b404721d http //www.rsc.org/is/joumals/current/ analyst/ anlpub.htm). 

Gennaro (51) proposed a method for the separation of water-soluble vitamins by means of the ion interaction reagent using octylamine < -phosphate or octylamine salicylate buffer (at pH 6.4) as the interaction reagent and the mobile phase at a flow rate of 1 mL/min, and a 2.5-p.m Spherisorb ODS C18 column (250 X 4.6 mm) as the stationary phase. The column effluent was monitored at 210 nm. Retention times of pantothenic acid obtained with octylamine t)-phos-phate and octylamine salicylate were 64.0 and 9.8 min. The method was used for the determination of pantothenic acid in a model mixture of water-soluble vitamins and also in a commercial multivitamin isotonic salt dietetic drink (Fig. 9). 

It could be demonstrated that the ionic liquids are useful as mobile phase additives in reversed phase chromatography of phenothiaz-ine derivatives. A very important feature of these additives is their ability to decrease the peak width. In the absence of such strong ion-ion interaction reagents, wide peaks for cationic analytes are usually observed (28). 

Fluoride, perchlorate, chloride, nitrite, phosphite, arsenate, nitrate, chlorate, sulphate, chromate, borofluoride, glycol-late, acetate,lactate, propionate, aceto-acetate, hydroxy-butyrate, chloro-acetate, isobutyrate and butyrate Ruthenium (ll-l). 10 phenanth- roline and ruthenium (1 l)-2,2 bi- pyridine mobile phases Ruthenium in 1 1 complexes used as ion interaction reagents Indirect spectrofluoro- metric [331]... 

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