Micro-Scale UV/Vis Spectrometric Batch Procedures by Use of an Internal Standard–A Green Chemistry Approach

ABSTRACT

One approach to minimize environmental impact of laboratory-based activities is the reduced use of potentially harmful substances. Regarding UV/Vis spectrophotometric procedures, they typically consist of several steps and may include solvent extraction or evaporation, dilution, chemical derivatization, and so on. To assure reliable analytical results, classical batch procedures are performed in volumetric vessels and require considerable amounts of different reagents and solvents. Quite importantly, many official analytical methods are based on UV/Vis spectrophotometric measurements and, to the best of our knowledge, no micro-scale batch procedure has been accepted so far. In order to enhance the performance of such micro procedures, the use of internal standard method (IS) had been proposed. The most important feature of IS in UV/Vis spectrophotometry is that less rigorous procedures become possible and, from the green chemistry point of view, the micro-scale batch procedures can be used without sacrificing the results quality. In this article, the general requirements for an IS in UV/Vis spectrophotometry and its applications in the procedures involving many-fold dilution or extraction/preconcentration of the analyte are presented, highlighting two aspects: (i) analytical performance and (ii) environmentally friendly protocols.

KEYWORDS:

• internal standard
• mirco-scale procedures
• UV/Vis spectrophotometry

Notes

DL––detection limit expressed as mg of Bi in 1 ml of sample digest; CV––variation coefficient for 5 replicates.

An invited paper submitted to a special issue on Green Spectroscopy and Analytical Techniques, organized by Professor Miguel de la Guardia, of the Department of Chemistry, University of Valencia, Spain, and Professor Arabinda Kumar Das, of the Department of Chemistry, University of Burdwan, West Bengal, India.