Molecular connectivity as a new and relevant tool to predict the analytical behaviour: A survey of chemiluminescence and chromatography

We present a critical presentation and discussion on molecular connectivity applied to analytical fields, giving special attention to predicting the chemiluminescent behavior of pharmaceuticals and pesticides. Molecular connectivity has been largely applied to predict the therapeutic effects of pharmaceuticals and rarely to predictions in analytical chemistry-basically to chromatographic processes and recently to liquid-phase chemiluminescence. (c) 2005 Elsevier Ltd. All rights reserved.Catalá Icardo, M.; Lahuerta Zamora, L.; Antón-Fos, GM.; Martínez Calatayud, J.; Duart, MJ. (2005). Molecular connectivity as a new and relevant tool to predict the analytical behaviour: A survey of chemiluminescence and chromatography. Trends in Analytical Chemistry. 24(8):782-791. doi:10.1016/j.trac.2005.01.015S78279124

Theoretical prediction of the chemiluminescence behaviour of the ergot alkaloids. Direct flow injection chemiluminescence determination of ergotamine tartrate

The present manuscript is dealing with the application of molecular connectivity calculations to predict the chemiluminescent behaviour of ergot alkaloids when they react with common strong oxidants in liquid phase. Twenty compounds were theoretically studied by means of a discriminant equation formerly published, being 19 of them predicted as chemiluminescent with a high probability. Empirical confirmation of the chemiluminometric behaviour is performed with the few soluble and commercially available ergot alkaloids. On the basis of these results, a new FIA-direct chemiluminescent method is proposed for the determination of the ergot presenting the higher light emission, the pharmaceutical ergotamine. The method is based on the oxidation of the drug by K3[Fe(CN)6] in sodium hydroxide medium, at seventy degrees and enhanced by the presence of dioxane. The studied calibration up to 5.0 mg l−1, revealed a linear dynamic graph up to 0.5 mg l−1. The reproducibility between days resulted in a rsd (in slope %) of 8.9 (n, 5) and the repeatability with a %R.S.D. (n = 20) of 1.9 and 0.6 for 0.3 and 4.0 mg l−1, respectively. LOD (s/n = 3) of 6 × 10−7 mg l−1 and sample throughput of 73 h−1. The influence of foreign compounds is also tested and the optimised flow-assembly is applied to other compounds of the ergot alkaloids family. © 2004 Elsevier B.V. All rights reserved.Polo Martí, E.; Catalá Icardo, M.; Lahuerta Zamora, L.; Antón Fos, GM.; Martínez Calatayud, J. (2004). Theoretical prediction of the chemiluminescence behaviour of the ergot alkaloids. Direct flow injection chemiluminescence determination of ergotamine tartrate. Analytica Chimica Acta. 527(2):177-186. doi:10.1016/j.aca.2004.07.026S177186527

QSPR studies on the photoinduced-fluorescence behaviour of pharmaceuticals and pesticides

<p>Fluorimetric analysis is still a growing line of research in the determination of a wide range of organic compounds, including pharmaceuticals and pesticides, which makes necessary the development of new strategies aimed at improving the performance of fluorescence determinations as well as the sensitivity and, especially, the selectivity of the newly developed analytical methods. In this paper are presented applications of a useful and growing tool suitable for fostering and improving research in the analytical field. Experimental screening, molecular connectivity and discriminant analysis are applied to organic compounds to predict their fluorescent behaviour after their photodegradation by UV irradiation in a continuous flow manifold (multicommutation flow assembly). The screening was based on online fluorimetric measurement and comprised pre-selected compounds with different molecular structures (pharmaceuticals and some pesticides with known ‘native’ fluorescent behaviour) to study their changes in fluorescent behaviour after UV irradiation. Theoretical predictions agree with the results from the experimental screening and could be used to develop selective analytical methods, as well as helping to reduce the need for expensive, time-consuming and trial-and-error screening procedures.</p