A simple and low cost dual-wavelength β-correction spectrophotometric determination and speciation of mercury(II) in water using chromogenic reagent 4-(2-thiazolylazo) resorcinol

A H Al-Bagawi; W Ahmad; Z M Saigl; H Alwael; E A Al-Harbi; M S El-Shahawi

doi:10.1016/j.saa.2017.06.044

A simple and low cost dual-wavelength β-correction spectrophotometric determination and speciation of mercury(II) in water using chromogenic reagent 4-(2-thiazolylazo) resorcinol

Spectrochim Acta A Mol Biomol Spectrosc. 2017 Dec 5:187:174-180. doi: 10.1016/j.saa.2017.06.044. Epub 2017 Jul 1.

Authors

A H Al-Bagawi¹, W Ahmad², Z M Saigl², H Alwael², E A Al-Harbi³, M S El-Shahawi⁴

Affiliations

¹ Department of Chemistry, Faculty of Science, Hail University, Hail, Saudi Arabia.
² Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia.
³ Department of Chemistry, Faculty of Science, Taibah University, Al-Madinah Al-Minawara, Saudi Arabia.
⁴ Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia. Electronic address: malsaeed@kau.edu.sa.

PMID: 28686919
DOI: 10.1016/j.saa.2017.06.044

Abstract

The most common problems in spectrophotometric determination of various complex species originate from the background spectral interference. Thus, the present study aimed to overcome the spectral matrix interference for the precise analysis and speciation of mercury(II) in water by dual-wavelength β-correction spectrophotometry using 4-(2-thiazolylazo) resorcinol (TAR) as chromogenic reagent. The principle was based on measuring the correct absorbance for the formed complex of mercury(II) ions with TAR reagent at 547nm (lambda max). Under optimized conditions, a linear dynamic range of 0.1-2.0μgmL^-1 with correlation coefficient (R²) of 0.997 were obtained with lower limits of detection (LOD) of 0.024μgmL^-1 and limit of quantification (LOQ) of 0.081μgmL^-1. The values of RSD and relative error (RE) obtained for β-correction method and single wavelength spectrophotometry were 1.3, 1.32% and 4.7, 5.9%, respectively. The method was validated in tap and sea water in terms of the data obtained from inductively coupled plasma-optical emission spectrometry (ICP-OES) using student's t and F tests. The developed methodology satisfactorily overcomes the spectral interference in trace determination and speciation of mercury(II) ions in water.

Keywords: 4-(2-Thiazolylazo) resorcinol; Dual-wave β-correction spectrophotometry; Interference; Mercury(II) determination; Method validation; Water samples.