Application of Response Surface Modeling and Chemometrics Methods for the Determination of Ofloxacin in Human Urine Using Dispersive Liquid-Liquid Microextraction Combined with Spectrofluorimetry

Abstract

Dispersive liquid-liquid microextraction (DLLME) and spectrofluorimetry, coupled with chemometrics methods, are proposed in this work for the pre-concentration and determination of ofloxacin concentration in spiked human urine. Chloroform and acetonitrile were selected as the extraction and dispersive solvents by the one-variable-at-a-time process. The Box-Behnken design was used to optimize the other variables, including the volume of extraction and dispersion solvents, solution pH, and ionic strength. A linear calibration curve was obtained in the 5.0-120.0 ng mL -1 range under optimal conditions with a detection limit of 1.61 ng mL -1 and correlation coefficient of 0.9948. A relative standard deviation (RSD) of 1.13% was obtained for seven consecutive replicates. Parallel factor analysis (PARAFAC) and partial least square (PLS) modeling were applied for the multivariate calibration of the spectrofluorimetric data. To pre-process the data matrices and predict the model results, the orthogonal signal correction (OSC) was used, and the analysis results were statistically compared. The methods accuracy values for ofloxacin determination, evaluated by the root mean square errors of prediction (RMSEP) and relative standard error of prediction (RSEP), were 0.82 and 1.12 using OSC-PLS, and 0.31 and 0.42 using OSC-PARAFAC models, respectively. Ofloxacin can be reliably determined in human urine samples through the proposed procedure, according to the results.

Recent applications of microextraction sample preparation techniques in biological samples analysis

“…In this study analytes were detected with LODs ranging from 0.2 to 2 ng/ml (Odoardi et al, 2015). Assadian and Niazi (2017) One year later Kaykhaei et al (2018) demonstrated DLLME combined with microvolume spectrophotometry to study iodine in urine samples. They used toluene as an extracting phase and ethanol as a dispersive solvent.…”

Determination of fenthion in environmental water samples by dispersive liquid–liquid microextraction coupled with spectrofluorimetric and chemometrics methods

“…Due to the low concentration of the analytes and the complex matrix of the samples, a preliminary sample preconcentration and a separation technique are required. Thus, different extraction processes have been used for separation and pre-concentration of trace pesticide residues, such as solid phase extraction method (SPE) [8][9][10][11], solid phase microextraction (SPME) [12], [13], single drop microextraction (SDME) [14] and dispersive liquid-liquid microextraction (DLLME) [15][16][17].…”

“…One of the most popular LPME techniques is dispersive liquid-liquid microextraction (DLLME) which is widely used as a preconcentration method [18][19][20][21]. DLLME was developed by Assadi and co-workers [16]. By consisting of the formation of a cloudy solution promoted by the fast addition in the aqueous sample of a mixture of extractor and dispersive solvents.…”

“…Response surface methodology (RSM) is powerful multivariate technique that used for building empirical model via collection of mathe-matical and statistical method. The main advantage of RSM is that it reduces the number of experiment because several factors can be varied simultaneously for optimization and as a result saves time, energy, and chemicals [16,37,38]. Box-Behnken design is the most common and efficient design used in RSM.…”

“…Box-Behnken design is a second order multivariate technique based on three level partial factorial designs. Box-Behnken is a spherical, rotatable or nearly rotatable that consists of a central point and with the midpoints of the edges of the variable space [15][16][17], [33,34]. Two dimensional excitation emission (EEM) fluorescence data can be obtained by measuring the emission spectra at various excitation wavelengths.…”