Determination of Cr(VI) concentration in diluted samples based on the paper test strip method

Abstract

At present, there are many methods for Cr(VI) concentration determination in diluted samples, however, these methods have their own inherent drawbacks, such as long response time, complicated pretreatment, expensive equipment etc. In this paper, a paper-based test strip method specific for determination of diluted Cr(VI) samples was developed. In this method, Aliquat 336, as an anion exchanger was loaded into filter paper to form a test strip. This test strip was used to pre-concentrate Cr(VI) when contacting with the diluted Cr(VI)-containing solution. The Cr(VI)-containing test strip was then immersed into a diphenylcarbazide (DPC) solution (a color forming solution), and the color intensity was correlated to the Cr(VI) concentration. The detection range of the present method was found to be 0.02-1.50 mg/L. The results also showed that the method gave a high selectivity for Cr(VI) in the diluted samples to be tested. The method was applied to synthesized samples and the results, which were compared to those from a reference method, showed that the developed method is an effective, reliable way for Cr(VI) determination in diluted samples.

Teaching the properties of chromium's oxidation states with a case study method

“…Chromium is one of the most frequently detected soil and groundwater contaminants due to its widespread use in industrial applications, such as leather tanning, metallurgy, electroplating, and refractory, which have resulted in chromium contamination of natural water (Oktor et al, 2008;Kumar and Riyazuddin, 2011). Chromium usually occurs in two oxidation states, trivalent chromium and hexavalent chromium (represented as Cr(III) and Cr(VI) respectively), which have different toxicities, mobility and bioavailability (Kong and Ni, 2009).…”

From kirigami to three-dimensional paper-based micro-analytical device: cut-and-paste fabrication and mobile app quantitation

“…33,34 The detection of Cr(VI) was traditionally based on the colorimetric reaction between 1,5diphenylcarbazide (DPC) and Cr(VI), which generates a magenta product [Cr(III)DPCO] (3Àn)+ . [35][36][37] While the NO 2 À concentration in water samples was quantitated with the Griess reaction, which also generates a magenta product (the principle of colorimetric reaction were shown in Fig. S6 †).…”

“…These values are comparable with the detection limits obtained with other colorimetric assays reported in literature. 34,37 Nevertheless, these calibration curves and the deduced equations for the signal-concentration correlations were incorporated to the kPAD_DET app that can be directly applied for the quantitation of unknown samples (vide infra).…”

Rapid Detection of Transition Metals in Welding Fumes Using Paper-Based Analytical Devices

“…In the presence of Cr(VI), the colorimetric reagent 1,5-DPC becomes oxidized to diphenylcarbazone, reacting with trivalent Cr to produce an intensely purple-hued complex (Fig. 1b) (Kong, 2009; Kong and Ni, 2009). …”