UV–vis spectrophotometry is a mature analytical technique applied to many thousands of determinations owing to its simplicity, flexibility, low cost and convenience [4]. Due to the widespread use of UV–vis spectrophotometers for routine analysis and as a result of the greatdemandto decrease the sample volume needed to perform a measurement, microvolume spectrophotometers have been commercialized. Despite these systems have been developed especially for molecular biology, biochemistry, and microbiology, they are useful in other science areas, among them, in combination with miniaturized sample preparation techniques used in analytical chemistry, as has been demonstrated in recent publications
[5–9].