A Rapid and Simple Spectrophotometric Determination of Traces of Chromium (VI) in Waste Water Samples and in Soil samples by using 2-Hydroxy, 3-Methoxy Benzaldehyde Thiosemicarbazone (HMBATSC)
A rapid and simple Spectrophotmetric method has been developed for the determination of microgram amount of Chromium (VI) in aqueous dimethyl formamide (DMF). Chromium (VI) forms a yellowish green coloured M:L complex with 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone in the acidic buffer medium (pH=6.0) at room temperature. The complex shows maximum absorption at 385nm. Beer's law is obeyed in the range 0.260 to 2.60 
Chromium Monitoring in Water by Colorimetry Using Optimised 1,5-Diphenylcarbazide Method
Chromium contamination of drinking water has become a global problem due to its extensive use in industry. The most commonly used methods for chromium detection in water are laboratory-based methods, such as atomic absorption spectroscopy and mass spectroscopy. Although these methods are highly selective and sensitive, they require expensive maintenance and highly trained staff. Therefore, there is a growing demand for cost effective and portable detection methods that would meet the demand for mass monitoring. Microfluidic detection systems based on optical detection have great potential for onsite monitoring applications. Furthermore, their small size enables rapid sample throughput and minimises both reagent consumption and waste generation. In contrast to standard laboratory methods, there is also no requirement for sample transport and storage. The aim of this study is to optimise a colorimetric method based on 1,5-diphenylcarbazide dye for incorporation into a microfluidic detection system. Rapid colour development was observed after the addition of the dye and samples were measured at 543 nm. Beer’s law was obeyed in the range between 0.03–3 mg·L−1. The detection limit and quantitation limit were found to be 0.023 and 0.076 mg·L−1, respectively.
Determination of silver with the thiosemicarbazone of picoline-2-aldehyde
Abstract Picoline-2-aldehyde thiosemicarbazone forms a stable complex with silver in the pH range 5.0 to 6.0. The complex has the metal:ligand ratio of 1:1. Complexation with silver at pH 5.5 in the presence of EDTA allows a selective determination to be performed. Of 21 cations studied, 1-fold molar ratio of mercury(II), 2-fold molar ratios of titanium and uranium, 5-fold molar ratios of copper (II) and hafnium and 8-fold molar ratio of scandium caused interference in the determination of 1.0 μmole of silver. Amongst 12 anions, a 1-fold ratio of bromide, iodide, and cyanide; 3-fold molar ratio of chloride; and 50-fold molar ratio of molybdate caused low results.