Dispersive Micro-solid Phase Extraction Method Research Articles

Determination of insecticide residues in beverages based on MIL-100(Fe) dispersive solid-phase microextraction in combination with dispersive liquid-liquid microextraction followed by HPLC-MS/MS

A novel dispersive solid-phase microextraction method based on a metal-organic framework (MIL-100(Fe)) combined with a dispersive liquid-liquid microextraction technique was proposed for the extraction and enrichment of four insecticides in beverages. The qualitative and quantitative analysis of these insecticides was conducted using HPLC-MS/MS. To optimize the extraction process, several parameters were investigated, and the main variables were optimized using CCD-based RSM. The developed method displayed a wide linear range of 1.000–1000 ng/L and R2 values >0.993 for all four calibration curves. The method demonstrated high sensitivity, with LODs and LOQs of 0.3–0.6 ng/L and 0.8–1.0 ng/L, respectively. In addition, the greenness of the proposed method was assessed using the Complex GAPI tool, and the results showed that the proposed method exhibits benefits, such as minimal usage of organic solvents and negligible matrix influence, making it a suitable method for the detection of insecticide residues in beverages.

Development of a dispersive micro-solid phase extraction method based on using cobalamin as a green adsorbent for the extraction of Cd(II) and Pb(II) from oil samples

ABSTRACT A dispersive micro-solid phase extraction procedure using cobalamin as a green sorbent has been developed for the extraction of Cd(II) and Pb(II) ions from oil samples. At first, a desired amount of oil sample was dissolved in chloroform. Then, the specified amount of cobalamin was added and vortexed. After centrifuging, the separated solid particles were dissolved in nitric acid solution. Finally, the analytes were analysed by flame atomic absorption spectrometry. Effects of different analytical parameters such as amounts of sample and cobalamin, vortex time, complexing agent amount, type and volume of dissolving solvent, and temperature on the extraction efficiency of Pb(II) and Cd(II) ions were investigated and optimised. Under optimised conditions, calibration curves were established with the linear ranges of 1.5–150 μg Kg−1 for Cd(II) and 1–150 μg Kg−1 for Pb(II). The detection limits were found to be 0.48 and 0.34 µg Kg−1 along with extraction recoveries of 89.1% and 94.8% for Cd(II) and Pb(II) ions, respectively. The proposed method demonstrated good repeatability, with the relative standard deviation ranging from 3.8% to 4.1% (n = 6, C = 10 μg Kg−1 of each cation). Finally, the method was successfully applied to determine the concentrations of Cd(II) and Pb(II) ions in various oil samples.

Simultaneous and rapid determination of three organophosphorus pesticides from vegetable and cereal samples with a magnetic dispersive solid-phase microextraction method by gas chromatography-mass spectrometry

ABSTRACT A straightforward and fast magnetic dispersive solid-phase microextraction method (MDSPME) as a sample preparation procedure coupled with gas chromatography/mass spectroscopy (GC/MS) was developed to measure three organophosphorus pesticides (OPPs), including ethion, diazinon, and chlorpyrifos, from fruit and cereal samples. Magnetic Fe3O4@ reduced graphene oxide nanocomposites as an excellent sorbent were synthesised based on several steps such as graphite oxide preparation, graphite oxide exfoliation, graphene oxide reduction, and chemical co-precipitation of magnetic Fe3O4 methods. Nine factors affected in the MDSPME procedure were thoroughly optimised using the design of experiment approach. The Plackett-Burman design and central composite design were utilised for screening the significant factors and for optimising the factors, respectively. The calibration curves of ethion, diazinon, and chlorpyrifos were linear in the ranges of 0.008–4.5, 0.01–4.0, and 0.01–4.5 ng ml−1 with R-squared of 0.9953, 0.9923, and 0.9981, respectively. The proposed method has high preconcentration factors (PF ≥ 220), low sample solution consumption (5.0 ml), and fast extraction time (5.0 min) for the OPPs determination. Analysis of real samples, including rice and cucumber samples, was shown that the proposed procedure is the suitable sample preparation and determination method for the measurement of OPPs with a recovery percentage in the range of 91.3%-102.2% and RSDs lower than 7.2%. The method has great advantages including low desorption solvent consumption, simple operation, and suitable RSDs for the OPPs determination in the fruit and cereal samples with complex matrices.

Environmentally friendly nanoflower Al2O3@carbon spheres as adsorbent for dispersive solid-phase microextraction of copper and lead in food and water samples.

A fast and simple dispersive solid-phase microextraction method (d-SPμE) was described for the determination of copper and lead in food, water, and sediments using FAAS. Firstly, nanoflower Al2O3@carbon spheres composite (NF Al2O3@CSs) was synthesized and then characterized. The obtained NF Al2O3@CSs was used for the d-SPμE of copper and lead in aqueous solutions. The influence of important parameters like pH, contact time, eluent conditions, volume of sample, and competing ion effects on the d-SPμE efficiency of copper and lead was investigated. They were pH, 7; eluent, 2 mol L-1 HCl (2 mL); sample volume, 250 mL for copper and 150 mL for lead with recoveries ≥90%. The adsorption and elution of analytes on NF Al2O3@CSs were realized quickly without vortexing. The LODs of the d-SPμE for copper and lead were found to be 0.69 μg L-1 and 2.8 μg L-1, respectively, while its PF was 125 for copper and 75 for lead. The intra-day precision and inter-day repeatability (RSD%, n = 7) were 1.3% and 1.6% for Cu(II) and 2.3% and 3.2% for Pb(II), respectively. Finally, the accuracy of the d-SPμE was investigated by determination of the analytes in four certified reference materials (TMDA-53.3 Lake water, NW-TMDA-54.6 Lake water, NIST 1573a Tomato leaves, and NIST RM 8704 Buffalo River Sediment). The analyte recoveries together with analyses of dam water, river water, wastewater, sea water, sumac, tea, chocolate, and lentils were studied. The results indicate that recoveries ranged from 90 to 103% in water samples and 91 to 110% in food samples.

A simple and green dispersive micro-solid phase extraction method by combined application of graphene oxide and a magnetic ionic liquid for selective determination of inorganic antimony species in water, tea and honey samples

A highly selective and efficient method based on the use of graphene oxide (GO) and a magnetic ionic liquid (MIL) for dispersive micro-solid phase extraction (D-μ-SPE) was developed for inorganic Sb speciation analysis. In this work, Sb(III) species was selectively complexed with sodium diethyldithiocarbamate (DDTC) and retained on 3 mg of GO. Afterwards, 40 μL of the MIL trihexyl(tetradecyl)phosphonium hexachlorodysprosiate(III) ([P6,6,6,14]3DyCl6) were added to instantly magnetize the sorbent surface followed by its separation using a magnetic rod. Then, the aqueous phase containing only Sb(V) was directly analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Total Sb concentration was obtained by direct introduction of the sample into ICP-MS instrument. Thus, Sb(III) was calculated based on the difference between the concentrations of total inorganic Sb and Sb(V). Extraction conditions were optimized by a multivariate study yielding a 99.7% extraction efficiency for Sb(III). Limits of detection of 5 ng L−1 for Sb(III) and 3 ng L−1 for Sb(V) and relative standard deviations of 3.2% for Sb(III) and 2.9% for Sb(V) (at 10 μg L−1 Sb(III) and Sb(V), n = 6) were obtained. The calibration linear range was 0.01–80 μg L−1. The proposed method was successfully applied for separation and determination of inorganic Sb species in tap water, tea infusions and honey samples. Furthermore, the greenness of the D-μ-SPE method was assessed by the use of the Analytical GREEnness calculator (AGREE), obtaining a value of 0.61.

Ultrasonic-assisted d-µ-SPE based on amine-functionalized KCC-1 for trace detection of lead and cadmium ion by GFAAS

In this work, an efficient ultrasonic-assisted dispersive micro-solid phase extraction method (ultrasonic-assisted d-µSPE), based on amine-functionalized mesoporous silica KCC-1, was successfully utilized for the extraction and highly sensitive detection of lead and cadmium ions in water and agricultural products. The lead and cadmium ions were determined by graphite furnace atomic absorption spectrometry (GFAAS). In addition, the impact of significant factors, including pH, sorbent mass, and the sonication time in the retention step and concentration of the eluent, volume of the eluent, and the sonication time in the elution step was optimized using the Box-Behnken design. The obtained models by the Box-Behnken design for the retention and elution steps were meticulously evaluated. The results show that the proposed models for predicting and optimizing influencing parameters in the pre-concentration procedure have good adequacy and accuracy. In the optimal pre-concentration conditions, the calibration curves were linear in the range of 0.08–1.4 µg/L for cadmium and 0.6–30 µg/L for lead ions. The limits of quantification (LOQ) and the limits of detection (LOD) were 0.08 µg/L and 0.02 µg/L for cadmium ions and 0.60 µg/L and 0.18 µg/L for lead ions. The obtained relative recovery values from the analysis of spiked real samples were in the 97.2–104.0 % and 98.0–107.0 % range for cadmium and lead ions, respectively. Intra-day and inter-day relative standard deviations were 4.4 and 6.1 % for cadmium ions and 2.9 and 4.9 % for lead ions (1.0 µg/L; Number of replicate = 3).

Determination of benzimidazoles in beef by molecularly imprinted boron nitride composite based dispersive solid phase microextraction and ultra performance liquid chromatography

The main objective of this study was to synthesize the molecularly imprinted boron nitride material and develop a high efficient method for extraction of the residue of veterinary drug in food sample. During the experiments, the molecularly imprinted microspheres with 2-aminobenzimidazole as the template were polymerize on boron nitride to synthesize a type of new composite. Then it was used as absorbent to develop a dispersive solid phase microextraction method for purification of benzimidazole drugs in beef followed by determination with ultra performance liquid chromatography. This composite could simultaneously recognize 7 benzimidazoles with high absorption capacity (36.23–38.88 μg/mg) and high recovery (92.3%-97.1%), and could be reused for 5 times. This sample extraction method achieved high enrichment factors (21.5–37.9), so the limits of detection for determination of the 7 drugs in beef were in the range of 0.2–0.5 ng/g. This is the first study reporting the use of boron nitride based material for the extraction of residual veterinary drug in food sample.

In-syringe dispersive micro-solid phase extraction method for the HPLC-fluorescence determination of aflatoxins in milk

The simultaneous determination of aflatoxins (B 1 , B 2 , M 1 and M 2 ) in milk using a new sample pretreatment technique, the in-syringe dispersive micro-solid phase extraction (ISDμSPE), coupled with high performance liquid chromatography with fluorescence detection is described. The separation of the aflatoxins were performed using C18 Hypersil gold (250 mm × 4.6 mm, 5 μm) column at 40 °C under gradient elution for 35 min. The excitation and emission wavelengths of the fluorescence detector were at 360 nm and 440 nm, respectively. On-line photo-chemical derivatization was used to enhance the detection of aflatoxin B 1. Several parameters such as type and amount of sorbent, vortex speed, vortex time and elution solvent were evaluated. Limits of detection (LOD) ranged from 0.003 to 0.005 ng mL −1 , limits of quantification (LOQ) ranged from 0.01 to 0.02 ng mL −1 , recoveries ranged from 73.0 to 109.6%, and relative standard deviations (RSDs) was less than 17.3%. The proposed method was succesfully applied to the analysis of aflatoxins in milk. • An alternative microextraction procedure for the simultaneous determination of aflatoxin M 1 , M 2 , B 1 and B 2 in milk. • Samples and sorbent are dispersed in the syringe allowing higher surface area for interaction. • Acetone was used to replace hazardous chlorinated solvents.

Application of curcumin as a green and new sorbent in deep eutectic solvent-based dispersive micro-solid phase extraction of several polycyclic aromatic hydrocarbons from honey samples prior to gas chromatography-mass spectrometry determination.

A green, simple, and efficient dispersive micro-solid phase extraction method was developed for the extraction of polycyclic aromatic hydrocarbons from honey samples. In this method, for the first time, curcumin was used as an efficient and green sorbent to extract the analytes from the sample. After that the adsorbed analytes were eluted using a deep eutectic solvent prepared by mixing tetrabutylammonium chloride: ethylene glycol and analyzed by gas chromatography-mass spectrometry. Important experimental factors affecting adsorption and desorption steps of the method were optimized and under optimal experimental conditions, low limits of detection (0.14-0.37ng/g) and quantification (0.49-1.3ng/g), wide linear range (1.3-500ng/g) with a coefficient of determination ≥0.994 were obtained. Relative standard deviation values for intra- and interday precisions were ≤7.5% for all of the analytes at a concentration of 2ng/g for each analyte (n=6). Extraction recovery of the method was in the range of 72-81%. Finally, 20 honey samples were analyzed and the analytes were successfully detected. The method is environment friendly because of the use of curcumin as a sorbent. Also, biodegradability of the used deep eutectic solvent components is another advantage of the method.

In situ adsorbent formation based dispersive micro-solid phase extraction using a deep eutectic solvent as an elution solvent for the extraction of some pesticides from honey samples prior to GC-MS analysis

In this work, a simple, inexpensive, green, and fast dispersive micro-solid phase extraction method has been developed for the extraction of several pesticides from honey samples. In this approach, a solution of curcumin was prepared in ethanol and it was dispersed into a sample solution with the aid of a syringe. Curcumin was precipitated in the sample solution as tiny particles and the analytes were adsorbed onto them. After centrifugation the adsorbed analytes were eluted with tetrabutylammonium chloride:dichloroacetic acid deep eutectic solvent. The dissolved analytes in the deep eutectic solvent were analyzed by gas chromatography-mass spectrometry. Parameters affecting the extraction efficiency of the method including sorbent amount, dispersive solvent type and volume, elution solvent type and volume, salting out effect, and sonication time were investigated. Extraction recovery of the method was obtained in the range of 70-83%. Also wide calibration ranges and low detection limits (0.22-0.81 ng g-1) were obtained. Relative standard deviation values for intra- and inter-day precisions were ≤10.2% for all analytes at a concentration of 5 ng g-1 of each (n = 6). Finally, ten honey samples were analyzed and data showed that all of the studied samples were free of the analytes.

Application of magnetic carbon nano-onions in dispersive solid-phase extraction combined with DLLME for extraction of pesticide residues from water and vegetable samples

A dispersive solid-phase microextraction method based on magnetic carbon nano-onions (MCNOs) was developed for the extraction and preconcentration of some pesticides from water and vegetable samples. For more cleanup and preconcentration, a dispersive liquid-liquid microextraction (DLLME) method was employed after performing the first step. In this method, firstly, MCNOs were prepared and then used for adsorption of the analytes from the sample solution. After that, the adsorbed analytes were eluted with an appropriate water-miscible organic solvent and used as a dispersive solvent in the following DLLME procedure. The extracted analytes were quantified by gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. Various factors affecting the method efficiency such as sorbent weight, salt effect, pH, temperature, and type and volume of eluent and extraction solvent were optimized. This method showed wide linear ranges with a coefficient of determination ≥ 0.994, and low limits of detection (0.001-0.005 ng mL-1) and quantification (0.003-0.019 ng mL-1) under optimal conditions. Also, a good precision (relative standard deviation ≤ 8.6%) for five replicates and a satisfactory accuracy (mean relative recoveries between 82 and 99%) were obtained. It can be considered as an efficient and environment friendly method for the extraction of analytes from vegetable and fruit juices and water samples.

Exfoliated graphitic carbon nitride nanosheets for on-line vortex-assisted dispersive micro-solid phase extraction of indium prior to determination by ICP-OES

ABSTRACT A new online vortex-assisted dispersive micro-solid phase extraction method was developed for the preconcentration of trace amounts of indium as a prior step to its determination by inductively coupled plasma-optical emission spectrometry. The methodology is based on the direct adsorption of In(III) ions by the graphitic carbon nitride nanosheets without using any chelating agent. In this method, after dispersion of sorbent particles into the sample solution, the resulting suspension was passed through a membrane filter and subsequently, the adsorbed In(III) ions were eluted from the membrane and directly introduced into the ICP-OES spectrometer. The developed on-line technique facilitates the conventional D-µSPE method by eliminating the centrifugation stage. Under the optimum conditions, the detection limit for the determination of In(III) was found to be 0.32 µg L−1. The developed method was employed for the preconcentration and quantitation of indium in various water samples.

Determination of Tetracyclines in Chicken by Dispersive Solid Phase Microextraction Based on Metal-Organic Frameworks/Molecularly Imprinted Nano-polymer and Ultra Performance Liquid Chromatography

In this study, the molecularly imprinted nano-polymer of minocycline was polymerized on the surface of a metal organic framework material to synthesize a novel composite. This composite was used as absorbent to develop a dispersive solid phase microextraction method for extraction of 7 tetracyclines in chicken muscle followed by determination with ultra performance liquid chromatography. The composite achieved high absorption capacities (2200–3000 ng/mg) and high recoveries (> 92%) for the 7 tetracyclines, and could be reused for 8 times. Due to the high enrichment factors (18–37), the limits of detection for the 7 drugs were in the range of 0.2–0.6 ng/g, and the limits of quantification were in the range of 0.5–2.0 ng/g. The recoveries of the 7 drugs from standard-fortified blank chicken muscle sample were in the range of 69.6–94.7%. Therefore, this method could be used as a practical tool for multi-detection of the residues of tetracyclines in meat.

Simultaneous determination of five penicillins in milk using a new ionic liquid-modified magnetic nanoparticle based dispersive micro-solid phase extraction followed by ultra-performance liquid chromatography-tandem mass spectrometry

As a highly efficient adsorbent, the DABCO-based ionic liquid modified Fe3O4 nanoparticles ([DABCO–C3OH]Cl@MNPs) has been successfully synthesized for the first time. The structure of nanoparticles was characterized by Field emission-scanning electron microscopy, Transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, vibrating sample magnetometer, and Zeta potential analysis. The modified magnetic nanoparticles were applied as a new sorbent for the enrichment of five penicillins in different milk samples by using for the dispersive micro-solid phase extraction method. The extracted penicillins, i.e., ampicillin, benzylpenicillin, amoxicillin, oxacillin, and cloxacillin, were subsequently analyzed by ultra-performance liquid chromatography-tandem mass spectrometry. Important factors associated with the extraction and desorption efficiency were optimized by the univariate method and response surface methodology. The proposed method was validated according to the recommendations of the Commission Decision 2002/657/EC and the Food and Drug Administration (FDA) guideline. Excellent linearity ranges were obtained with correlation coefficients over 0.998, and the relative standard deviation values for the intra-day and inter-day precision were less than 5.8% with the extraction recoveries ranged from 87% to 107%. The limits of detection for the established method were found to be 0.03–0.20 µg kg−1. The originally established pretreatment and detection method has some merits, such as less solvent consumption, higher sensitivity, lower matrix effect, and easy operation. And the [DABCO–C3OH]Cl@MNPs exhibited potential as an efficient adsorbent in the extraction of the analytes from dairy products.

Cyanopropyl-functionalized nanosilica based dispersive micro-solid phase extraction method for rapid removal of organophosphorus pesticides from water samples

Cyanopropyl-functionalized nanosilica based dispersive micro-solid phase extraction method for rapid removal of organophosphorus pesticides from water samples

The dispersive micro-solid phase extraction method for MS-based lipidomics of human breast milk

A simple and rapid microextraction method ensuring high lipidome coverage was developed for liquid chromatography mass spectrometry (LC-MS)-based lipidomics of human breast milk. The dispersive microsolid phase extraction (D-µ-SPE) technique, coupled with the design of experiment (DoE) method, enabled the study of the influence of several conditions (desorption solvent, stationary phase ratio, and sorption and desorption time) on the lipid extraction process of various lipid classes. The D-µ-SPE-based method, which used a mixture of C18 and zirconia-coated silica gel as the sorbent, allowed for the extraction of a wide range lipid classes characterized by different concentration levels. The developed method simplified the extraction procedure for lipidomics without loss of good reproducibility (70% of the MFs had peak volume%RSD <20% for all the tested stationary phases). The highest lipidome coverage was achieved when 100 µL of the human breast milk (HBM) sample was extracted using 27 mg of C18 mixed with 3 mg of zirconia-coated silica gel as the sorbent and methanol:2-propanol: ammonium hydroxide (14:81:5 v/v/v) mixture as the desorption solvent. The sorption and desorption time did not influence the number of extracted molecular features. The advantages of the present method over the traditional SPE and liquid-liquid extraction (LLE) commonly used in lipidomics are the possibility of mixing sorbents with various sorption mechanisms, which ensures high lipidome coverage, and the use of a small number of materials, including the sorbent and organic solvent.

Vinyl-functionalized mesoporous carbon for dispersive micro-solid phase extraction of azole antifungal agents from aqueous matrices

ABSTRACT A simple, rapid and sensitive vinyl-functionalized mesoporous carbon-based dispersive micro-solid phase extraction method has been developed for the preconcentration and quantification of azole antifungal drugs in aqueous matrices. The effects of type of adsorbent, desorption solvent, amount of adsorbent, pH, desorption time, salt addition and extraction time were investigated. Under the optimized conditions, the method demonstrated good linearity over the range of 1–300 µg L−1 for water sample and 5–400 µg L−1 for biological samples, low limits of detection (0.4 µg L−1 to 1.6 µg L−1), good analyte recoveries (89.8–113.9%) and acceptable RSDs (7.5–13.4%).

MgO-ZnO/carbon nanofiber nanocomposite as an adsorbent for ultrasound-assisted dispersive solid-phase microextraction of carbamazepine from wastewater prior to high-performance liquid chromatographic detection

A simple, rapid, and efficient ultrasound-assisted dispersive solid-phase microextraction (UA-DSPME) method was developed for the preconcentration of carbamazepine (CBZ) in wastewater prior to high-performance liquid chromatography coupled with diode array (HPLC-DAD) determination. The carbon nanofibers coated with magnesium oxide-zinc oxide (MgO-ZnO@CNFs) nanocomposite was used as an efficient adsorbent in magnetic dispersive solid-phase microextraction method. The structural and morphological properties of the nanocomposite were characterized by scanning electron microscopy and energy dispersive spectroscopy, transmission electron microscopy, X-ray diffractometer, and Fourier transform infrared spectroscopy. The surface area was investigated using Brunauer–Emmett–Teller. Several factors (such as pH, mass of adsorbent, extraction time, and eluent volume) that affect extraction and preconcentration of CBZ were also assessed and optimized using response surface methodology based on central composite design. Under optimal conditions, the limits of detection (LOD) and quantification were 0.08 μg L−1 and 0.29 μg L−1, respectively. The calibration curve constructed after preconcentration of seven successive standards was linear in the concentration range of 0.3–800 μg L−1 with the correlation coefficient of 0.9922. The intra-day and inter-day precisions expressed in terms of relative standard deviation were 1.4% and 4.2%. A preconcentration factor of 490 was achieved, and the method was applied for the analysis of spiked wastewater. Satisfactory recoveries ranging from 97.8 to 102% were obtained.

Dissolvable layered double hydroxide as a sorbent in dispersive micro‐solid phase extraction for the determination of acidic quinolones in honey by HPLC

This study presents a simple and green dispersive micro-solid phase extraction method for preconcentration of acidic quinolones from honey prior to high performance liquid chromatography determination. A two-dimensional nanostructured zinc-aluminum layered double hydroxide was synthesized and used as the sorbent for dispersive micro-solid phase extraction. Its different characteristics from conventional sorbents is that it is dissolvable in acidic solution (pH<4). After the extraction, the analyte elution step was omitted and thus the use of organic solvents was avoided. The key parameters influencing the extraction efficiency such as the amount of sorbent, pH of sample solution, vortex time, type and volume of acidic solution were investigated and optimized. The method exhibited low limits of detection (3.0-5.0ng/g), good linearity (10-2000ng/g) with coefficients of determinations higher than 0.9991, acceptable precision (RSD<9.1%) and accuracy (RE<5.8%). The proposed method is fast, efficient, eco-friendly, and suitable for the determination of acidic quinolones in honey samples.

Application of a new sample preparation method based on surfactant-assisted dispersive micro solid phase extraction coupled with ultrasonic power for easy and fast simultaneous preconcentration of toluene and xylene biomarkers from human urine samples

A fast and easy surfactant-assisted dispersive micro-solid phase extraction method coupled with ultrasonic power was used for the simultaneous preconcentration and determination of low levels of hippuric and methyl hippuric acid in human urine samples. In the first step, magnetic nanoparticles was coated by titanium oxide nanoparticles (Fe3O4/TiO2 NPs), afterward characterized by the scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier-transform infrared spectroscopy. In the next step, anionic surfactants were thus combined with the synthesized magnetic nanoparticles to create a new adsorbent for increasing the simultaneous extraction of hippuric and methyl hippuric acid. After elution of extracted target molecules by the sorbent, the concentration of these molecules were measured by high-performance liquid chromatography (HPLC–UV). Meanwhile, a statistical approach known as Box–Behnken design was applied for optimizing significant parameters. With the optimum parameters anticipated by the experimental design, the limit of quantification (LOQ) acquired was reported to be 3 µg L− 1, and the calibration curve was linear within the concentrations of 3–1000 µg L− 1. Finally, the method was effectively implemented for the determination of low levels of hippuric and methyl hippuric acid in human urine samples.