Computer vision-based analytical chemistry applied to determining iron in commercial pharmaceutical formulations.

Two different computer vision-based analytical chemistry (CVAC) methods were developed to quantify iron in the commercial pharmaceutical formulations Ferbisol® and Ferro sanol®. The methods involve using a digital camera or a desktop scanner to capture a digital image of a series of Fe2+ standard solutions and the unknown sample upon reaction with o-phenanthroline. The images are processed with appropriate software (e.g., the public domain programme ImageJ, from NIH) to obtain a numerical value (analytical signal) based on colour intensity. The fact that such a value is proportional to the analyte concentration allows one to construct a calibration graph from the standards and interpolate the value for the sample in order to determine its concentration. The results thus obtained were compared with those provided by a spectrophotometric method and the US Pharmacopoeia's recommended method. The differences never exceeded 2%. The two proposed methods are simple and inexpensive; also, they provide an effective instrumental alternative to spectrophotometric methods which can be especially beneficial in those cases where purchasing and maintaining a spectrophotometer is unaffordable.

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

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.