Simultaneous Spectrophotometric Determination of Some Polycyclic Aromatic Hydrocarbons Using Chemometrics Methods after Their Preconcentration by Salting-Out Assisted Liquid-Liquid Extraction

Document Type: Original research article


1 Department of Chemistry, Faculty of Science Islamic Azad University, Arak Branch, Arak, Iran

2 Department of Chemistry, Central Tehran Branch, Islamic Azad University, Tehran, Iran

3 Department of Chemistry, Faculty of Science Lorestan University, Poldokhtar Branch, Poldokhtar, Iran


A rapid, powerful, satisfactory and modified signal-pre-processing method that is a hybrid of the wavelet transform with orthogonal signal correction (OSC) is used for pre-processing of spectrophotometric data of naphthalene, anthracene and pyrene as analytes after their preconcentration by salting-out assisted liquid–liquid extraction (SALLE) method. Water-miscible extraction solvent (1.0 mL of acetonitrile) and a suitable amount of salt (1.0 g of (NH4)2SO4) are added into the aqueous solution (4.0 mL) and dissolved using a vortex leading to the occurrence of phase separation. The target analytes in the sample was extracted into the water-miscible extraction solvent. After extraction, the absorbance of the analytes mixture was measured in the wavelength range of 200-400 nm. The wavelet orthogonal signal correction (WOSC) was established for denoising and reduction of spectrophotometric data and hybrid with partial least squares (PLS) regression method for simultaneous determination of the studied analytes after the SALLE procedure. The influence of various parameters, such as extraction solvent and volume, type and amount of salt, vortex time and sample pH were studied and optimized. The net analyte signal (NAS) method was used for calculating figures of merit. Linear range (LR) of calibration graphs for naphthalene, anthracene and pyrene were between 0.20 - 2.00, 0.10 - 1.50 and 0.07 -1.00 µg mL-1, respectively. The obtained model showed good prediction capability with root mean square error of prediction (RMSEP) of 0.030, 0.024 and 0.013 µg mL-1 for naphthalene, anthracene and pyrene, respectively. The simple WOSC-PLS method has been successfully applied for the simultaneous determination of these analytes in the spiked wastewater samples.


[2] M. Onozato, A. Nishigaki, S. Ohshima, The Fate and Behavior of Polycyclic Aromatic Hydrocarbons (PAHs) Through Feeding and Excretion of Annelids, Polycycl Aromat Compd 30 (2010) 334-345.

[4] L. Gao, S. Ren, Prediction of nitrophenol-type compounds using chemometrics and spectrophotometry, Anal. Biochem. 405 (2010) 184-191.

[7] R. Heydari, S. Zarabi, Development of combined salt- and air-assisted liquid–liquid microextraction as a novel sample preparation technique, Anal. Methods 6 (2014) 8469-8475.

[10] A. Cañas, P. Richter, G.M. Escandar, Chemometrics-Assisted Excitation-Emission Fluorescence Spectroscopy on Nylon-Attached Rotating Disks. Simultaneous Determination of Polycyclic Aromatic Hydrocarbons in the Presence of Interferences, Anal. Chim. Acta 852 (2014) 105-111.

[11] A. Amraei, A. Niazi, Partial Least Square and Parallel Factor Analysis Methods Applied for Spectrophotometric Determination of Cefixime in Pharmaceutical Formulations and Biological Fluid, Iran. J. Pharm. Res. 17 (2018) 1191-1200.

[14] A. Amraei, A. Niazi, M. Alimoradi, M. Hosseini, Cloud Point Extraction and Simultaneous Spectrophotometric Determination of Allura Red and Carmoisine using Wavelet Orthogonal Signal Correction–Partial Least Squares Method,  J. Anal. Chem. 2 (2019) 93-99.

[15] R.N. Feudale, Y. Liu, N.A. Woody, H. Tan, S.D. Brown, Wavelet orthogonal signal correction, J. Chemom. 19 (2005) 55-63.

[17] S.J. You, N. Park, E.D. Park, M.J. Park, Partial least squares modeling and analysis of furfural production from biomass-derived xylose over solid acid catalysts, J. Ind. Eng. Chem. 21 (2015) 350-355.

[18] P. Geladi, B.R. Kowalski, Partial least-squares regression: a tutorial, Anal. Chim. Acta 185 (1986) 1-17.

[28] H.T.K. Britton, R.A. Robinson, Universal buffer solutions and the dissociation constant of veronal, J. Chem. Soc. (1931) 1456-1462.
[29] A. Gure, F.J. Lara, D.M. González, N. Megersa, M.D. Olmo-Iruela, A.M. García-Campaña, Salting-out assisted liquid–liquid extraction combined with capillary HPLC for the determination of sulfonylurea herbicides in environmental water and banana juice samples, Talanta 127 (2014) 51-58.

[30] A. Lorber, K. Faber, B.R. Kowalski, Net Analyte Signal Calculation in Multivariate Calibration, Anal. Chem. 69 (1997) 1620- 1626.

[31] A. Espinosa-Mansilla, M.I. Acedo Valenzuela, A. Muñoz de la Peña, F. Salinas, F. Cañada Cañada, Comparative study of partial least squares and a modification of hybrid linear analysis calibration in the simultaneous spectrophotometric determination of rifampicin, pyrazinamide and isoniazid, Anal. Chim. Acta. 427 (2001) 129-136.

[32] A. Amraei, A. Niazi, M. Alimoradi, Wavelength region selection and spectrophotometric simultaneous determination of naphthol isomers based on net analyte signal, Iran. Chem. Commun. 5 (2017) 207-216.

[35] A. Saleh, Y. Yamini, M. Faraji, M. Rezaee, M. Ghambarian, Ultrasound-assisted emulsification microextraction method based on applying low density organic solvents followed by gas chromatography analysis for the determination of polycyclic aromatic hydrocarbons in water samples, J. Chromatgr. A 1216 (2009) 6673-6679.