The colorimetric determination of cadmium, chromium, copper, iron, lead, manganese, nickel and zinc in sewage and industrial wastes

Abstract

The more commonly occurring metallic salts in industrial effluents are those of cadmium, chromium, copper, iron, lead, manganese, nickel and zinc, and their determination in concentrations as low as 0.1 p.p.m. is necessary. Various simple colorimetric procedures were tested, and the amount of interference caused by other metal ions was noted and, if possible, eliminated. As well as being suitable for measurement in photo-electric absorptiometers, the colours can be measured in visual colorimeters or by visual comparison with a row of standards in Nessler tubes.The method finally recommended is given in full only if it differs from published procedures; if a simple amendment suffices or if the published method is completely satisfactory, the reference to the original publication is considered sufficient. Methods published for cadmium,2 lead by the mono-colour dithizone procedure3 and nickel by dimethylgly~xime~ were found to be satisfactory for the types of sample concerned, and are not dealt with further in this paper.Procedures are recommended for chromium, copper, iron, manganese and zinc and, although the methods are not original, they are set out in some detail, as no one reference could be found to incorporate all the modifications required.

Corrosion process of stainless steel in natural brine as a source of chromium and iron – the need for routine analysis

“…The chloride matrix may disturb the reaction of Cr( vi ) with DPCI, leading to the formation of the Cr( iii )–DPCO complex. 40 It also interferes with the oxidation of chromium by KMnO 4 as Cl − ions are oxidized to Cl 2 . A preliminary study was performed based on spectrophotometric determination of Cr in diluted therapeutic brine spiked with Cr( vi ) standard to obtain the final concentration of 0.1 μg mL −1 .…”

Luminometric Label Array for Quantification and Identification of Metal Ions

“…Methods generally suffer from the interfering metal ions and need for different assay protocols, modified synthesized ligands, and absorption wavelengths. Thus, each metal ion requires its own assay protocol, incubation times, and reagents. − Fluorometric methods utilize specific fluoroionophores containing a receptor with metal binding site and fluorescent reporter. The fluoroionophores − based on the receptors, such as cryptands, , (aza-)­crown ethers, EDTA-derivatives, BAPTA, , nitrilotriacetic acid, or dipicolylamine, − have been developed as selective for each analyte metal ion.…”