Ion-exchange cartridges

Ion-exchange cartridges have also been used. Moriyasu et al. (40) used Bond Elut SCX in the purification of aspartame using a mixture of methanol 15% sodium chloride (1 1, v/v). Bond Elut SCX connected to Bond Elut C18 was used in the purification of aspartame and diketopiperazine, which were eluted with 20% acetonitrile (40,80). Ibe et al. (81) adsorbed aspartame on Amberlite CG-120 and eluted with a 2 N HC1 methanol (1 1, v/v) mixture. 

BenzylpenicUlin (PCG), phenoxymethylpeniciUin (PCV), oxacillin (MPIPC), cloxaciUin (MCIPC), nafcillin (NFPC), and dicloxacillin (MDIPC), aU of which are representative weakly acidic penicUlins, are widely used as veterinary drugs for livestock. We have reported, in our previous studies, the applicability of sample cleanup with an ion-exchange cartridge, in combination with ion-pair HPLC, for the analysis of ionizable compounds. We therefore applied the same technique to develop an analytical method for the quantitative determination of these residual penicillins in bovine muscle, kidney, and liver. ... 

It is desirable to use the same solution for HPLC mobile phase and for the elution solvent from the cleanup cartridges to assure good reproducibility of the HPLC determination of the penicillins. After the investigation of the selected ion-exchange cartridges using 2 mL of the above-described mobile phase as the elution solvent, Sep-Pak Accell Plus QMA (QMA) produced the best results with all of the penicillins being completely eluted. 

Ito, Y. Ikai, Y. Oka, H. Matsumoto, H. Kagami, T. Takeha, K. Application of ion-exchange cartridge clean-up in food analysis, in. Determination of henzylpenicillin, phenox3methylpenicilhn, oxacillin, cloxacillin, nafcillin, and dicloxacillin in hovine hver and kidney hy liquid chromatography with ultraviolet detection. J. Chromatogr., A 2000, 880, 85-91. 

Reverse phase cartridges should be washed with 6-10 holdup vol of acetonitrile or methanol. Ion-exchange cartridges should be washed with 6-10 vol of methanol (optional). Normal phase columns do not require a wash step. 

In addition to drinking water and environmental applications, water purity is critical to many industries. Conductivity detectors are used in semiconductor and chip fabrication plants, to monitor cleanliness of pipelines in the food and beverage industry, to monitor incoming water for boilers to prevent scale buildup and corrosion. Any process stream with ions in it can be analyzed by conductometry. Conductivity detectors are part of commercial laboratory deionized water systems, to indicate the purity of the water produced and to alert the chemist when the ion-exchange cartridges are exhausted. The detector usually reads out in resistivity theoretically, completely pure water has a resistivity of 18 MO cm. 

Analytical quantification of BAs may be difficult due to the complexity of some food matrices and the low concentrations of BAs generally encountered in the majority of foodstuffs. In addition, the low volatility of these compounds and the lack of chromophores for most of the BAs, does not allow the rapid direct detection by ultraviolet and visible (UV and vis) spectrometric or fluorimetric (FL) methods. In general, in order to obtain an optimal analysis, extraction, clean-up, concentration, and derivat-ization procedures are required. Extraction methods usually based on liquid-liquid or solid-phase extraction with C18 or ion-exchange cartridges can be applied to improve selectivity and sensitivity (Giannotti et al., 2008 Pena-Gallego, Hemdndez-Orte, Cacho, Ferreira, 2009). Alternative approaches, such as solid-phase microextraction... 

Sun XH, Liu JF, o WD, Yang XR, Wang EK, Fung YS (2002) Capillary electrophoresis with electrochemiluminescence detection of procyclidine in human urine pretreated by ion-exchange cartridge. Anal Chim Acta 470(2) 137-145. doi 10.1016/s0003-2670(02)00780-8... 

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