Ghobad Mansori; Mohammad_Bagher - Gholivand; Zarrin - Es'haghi
Abstract
For the first time, an analytical methodology based ondifferential pulse voltammetry (DPV) at a glassy carbon electrode (GCE) assisted by two multivariate calibration (MVC) models including back propagation-artificial neural network (BP-ANN), non-linear class, and partial least squares-1 (PLS-1), classical ...
Read More
For the first time, an analytical methodology based ondifferential pulse voltammetry (DPV) at a glassy carbon electrode (GCE) assisted by two multivariate calibration (MVC) models including back propagation-artificial neural network (BP-ANN), non-linear class, and partial least squares-1 (PLS-1), classical class, thatthey have been constructed on the basis of non-bilinear first order differential pulse voltammetry (DPV) data,was developed and validated for the simultaneous determination of Ascorbic acid, Uric acid, Acetaminophen, and Noradrenalinto identify which approach offers the best predictions.The baselines of the DPV signals were corrected by asymmetric least square spline regression (AsLSSR) algorithm. Before applying the PLS-1,lack of bi-linearity was tackled by potential shift correction using correlation optimised warping (COW) algorithm. The multivariate calibration (MVC) model was developed as a quaternary calibration modelin a blank human serum sample (drug-free) provided by a healthy volunteer to regard the presence of a strong matrix effect which may be caused by the possible interferents present in the serum, and it was validated and tested with two independent sets of analytes mixtures in the blank and actual human serum samples, respectively.According to the obtained results, the PLS-1 was recommended for simultaneous determination of AA, UA, AC, and NA in both blank and actual human serum samples .
Ahmadreza Amraei; Mohammad Hosseini; Rouhollah Heydari; Ali Niazi
Abstract
Simultaneous spectrophotometric determination of some polycyclic aromatic hydrocarbons (PAHs) in wastewater samples after preconcentration by salting-out assisted liquid-liquid extraction was achieved using a doolittle multivariate calibration algorithm (DMCA). The DMCA was applied by lower and upper ...
Read More
Simultaneous spectrophotometric determination of some polycyclic aromatic hydrocarbons (PAHs) in wastewater samples after preconcentration by salting-out assisted liquid-liquid extraction was achieved using a doolittle multivariate calibration algorithm (DMCA). The DMCA was applied by lower and upper (LU) triangular matrix decomposition which is efficient, powerful and easily. Results were shown that DMCA has advantages such as, simplicity, rapidness, avoiding matrix inverting and reducing the orders of matrices. 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 root mean square errors of prediction (RMSEP) for naphthalene, anthracene and pyrene using DMCA model were 0.0367, 0.0331 and 0.0305, respectively.
Ahmadreza Amraei; Ali Niazi; Mohammad Alimoradi; Mohammad Hosseini
Abstract
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 ...
Read More
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.
