羧基化多壁碳纳米管固相萃取-液相色谱-串联质谱法测定环境水体中四溴双酚A和双酚A

建立了羧基化碳纳米管固相萃取-液相色谱-串联质谱联用检测环境水体中四溴双酚A和双酚A的方法。比较了多壁碳纳米管、C60和羧基化多壁碳纳米管作为固相吸附剂对水体中四溴双酚A和双酚A的吸附效率。固相萃取浓缩后的样品经Thermo Scientific Hypersil C18色谱柱（150 mm×4.6 mm,3 μm）分离,采用串联质谱负离子模式进行检测。结果表明,四溴双酚A和双酚A在0.02~1.0 mg/L范围内具有良好的线性关系（r²≥0.99）,空白样品中的检出限（S/N=3）分别为0.04 μg/L和0.2 μg/L。将所建立的方法应用于实际环境水体中四溴双酚A和双酚A的检测,添加回收率在82%~99%之间,精密度小于5.0%,该方法可用于复杂环境样品中痕量四溴双酚A和双酚A的检测。     

Preparation of cyano-functionalized multiwalled carbon nanotubes as solid-phase extraction sorbent for preconcentration of phenolic compounds in environmental water

In the present work, we showed a novel method to synthesize cyano-functionalized multiwalled carbon nanotubes (MWCNTs-CN) and utilize it as a solid-phase extraction sorbent for preconcentration of phenolic compounds in environmental water samples. MWCNTs-CN was synthesized through surface functionalization of multiwalled carbon nanotubes (MWCNTs). The functional groups on the surface of modified MWCNTs were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. The analytical procedure was based on a conventional solid-phase extraction step for which 100 mg of MWCNTs-CN were packed in a 3 mL polypropylene cartridge. Analytes were thus isolated and preconcentrated from the pretreated samples and subsequently detected on high-performance liquid chromatography-ultraviolet detection. The results showed the proposed method exhibited good sensitivity and precision for the extraction and elution of analytes. The limit of detections (S/N = 3) of the method were 0.45, 0.09, 0.08, and 3.00 ng mL(-1) for p-chlorophenol, 1-naphthol, 2-naphthol, and 2,4-dichlorophenol, respectively. The mean relative recoveries (n = 3) were between 80.28 and 103.13%, and the repeatability (RSD ≤ 5.10%) and reproducibility (RSD ≤ 7.68%) were accepted. This developed method was applied to determine phenolic compounds in environmental water samples. There is a positive result only for 2-naphthol with concentration of 0.38 ng mL(-1) in seawater sample.     

Multiwalled carbon nanotubes as efficient adsorbent for solid-phase extraction of chemical warfare agents and related chemicals from water

Optimization of extraction and enrichment parameters of chemical warfare agents and their related chemicals from water are presented using multiwalled carbon nanotubes (MWCNTs) as solid-phase extractant. Selected analytes were O,O'-dialkyl alkylphosphonates, nerve agent and mustards. Extraction parameters, including sample volume, nature and volume of washing and eluting solvent, were optimized. Recoveries of analytes were determined by GC-MS and ranged from 81 to 104%. A comparison with C(18), hydrophilic-lipophilic balance and active carbon sorbents demonstrated the superiority of MWCNTs for non-toxic analogues of nerve agents. Optimized conditions involve 40?mg MWCNTs as the sorbent, 5.0?mL water as the washing solvent, 3?mL ethyl acetate as the eluent and sample loading of 10?mL water spiked at 0.1?μg/mL. The limits of detection (LOD) were achieved down to 1 and 0.05?ng/mL in full scan and selected ion-monitoring modes, respectively.     

Highly stable magnetic multiwalled carbon nanotube composites for solid-phase extraction of linear alkylbenzene sulfonates in environmental water samples prior to high-performance liquid chromatography analysis

The magnetic multiwalled carbon nanotubes (MMWCNTs) have been successfully prepared using a one-pot chemical coprecipitation method, in which magnetic nanoparticles (MNPs) were deposited onto multiwalled carbon nanotubes (MWCNTs) by in situ high temperature decomposition of the magnetic precursor of iron(III) in ethylene glycol media. A novel procedure for extraction of linear alkylbenzene sulfonates (LAS) as a model compound was thus developed in an off-line extraction system with detection by HPLC. The procedure includes the separation and preconcentration of LAS homologues onto MMWCNTs at pH 7.0 and their subsequent detection after sonication elution, followed by the separation of the MMWCNTs from the aqueous phase by external magnetic field and washing with ultra pure water. With a sample volume of 500 mL and 100 mg MMWCNTs sorbents, an enrichment factor of about 500, and a detection limit of 0.013-0.021 μg L(-1) were obtained within a linear range of 0.5-100 μg L(-1), together with a correlation coefficient of 0.9938-0.9998 for four LAS homologues. A precision of 2.4-5.6% was obtained for six replicate determinations of 50 μg L(-1) LAS. The recoveries of LAS homologues spiked in environmental water samples ranged from 87.3 to 106.3%, demonstrating the utility of the MMWCNTs adsorbents in a series of water samples. Stability testing demonstrated that the MMWCNTs remained 95.0% recovery for the target LAS even after a run of 50 adsorption and desorption cycles, showing their super operational stability. The MMWCNTs are promising adsorbents, suitable for the long-term repetitive sorption/desorption of target compounds in environmental water samples.     

Extraction of methocarbamol from human plasma with a polypyrrole/multiwalled carbon nanotubes composite decorated with magnetic nanoparticles as an adsorbent followed by electrospray ionization ion mobility spectrometry detection†

In this work, a polypyrrole/multiwalled carbon nanotubes composite decorated with Fe₃O₄ nanoparticles was chemically synthesized and applied as a novel adsorbent for the extraction of methocarbamol from human plasma. Electrospray ionization ion mobility spectrometry was used for the determination of the analyte. The properties of the magnetic‐modified adsorbent were characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform IR spectroscopy, and X‐ray diffraction. The effects of experimental parameters on the extraction efficiency of the sorbent were investigated. Under the optimized conditions, the linear dynamic range was found to be 2–150 ng/mL with the detection limit of 0.9 ng/mL. The relative standard deviation was 5.3% for three replicate measurements of methocarbamol in plasma sample. The extraction efficiency of the sorbent for the determination of different drugs with various polarities was also compared to that of Fe₃O₄‐polypyrrole and Fe₃O₄‐multiwalled carbon nanotubes sorbents. Finally, the method was used for the determination of methocarbamol in blood samples.     

Magnetic solid-phase extraction based on magnetic carbon nanotube for the determination of estrogens in milk

In this work, a novel method for the fabrication of magnetic carbon nanotubes based on 'aggregation wrap' was proposed. When carbon nanotubes and magnetic nanoparticles were vortically mixed in a solvent, the magnetic nanoparticles were wrapped into the carbon nanotube bundles that formed during the aggregation process, leading to the formation of magnetic carbon nanotubes. Thus, the resultant material can be separated from the solvent rapidly and conveniently by a magnet. Our investigation demonstrated that the 'aggregation wrap' mechanism for the preparation of magnetic composite is also applicable to other self-aggregated micro/nanomaterials, including graphene, graphite, C(60), etc. To testify the feasibility of the magnetic composites in sample preparation, the resultant magnetic carbon nanotubes were applied as sorbents for magnetic solid-phase extraction (MSPE) of estrogens in milk samples. Under optimized conditions, a rapid, convenient and efficient method for the determination of estrogens in milk samples was established by the combination of MSPE with high-performance liquid chromatography with fluorescence detector. The linearity range of the proposed method was 5-2000 μg/L with correlation coefficients (R) of 0.9983-0.9994. The limit of detection (LOD) for three estrogens ranged from 1.21 to 2.35 μg/L. The intra- and inter-day relative standard deviations (RSDs) were <9.3%. The reproducibility of the MSPE with different batches of magnetic carbon nanotubes was acceptable with RSD values <3.6%.     

Magnetic retrieval of chitosan: extraction of bioactive constituents from green tea beverage samples

A new solid-phase extraction mode for magnetic retrieval of chitosan combined with high-performance liquid chromatography-diode array detection was proposed for the pre-concentration and determination of flavonoids in green tea beverage samples. In the experiment, chitosan was used as sorbents for the extraction of target analytes; after completion of the extraction process, Fe(3)O(4) nanoparticles acted as carrier to retrieve chitosan from the sample solution. Some important parameters influenced extraction efficiency of flavonoids, including the extraction mode, amounts of chitosan, pH of sample solution, extraction time, salt addition, amounts of Fe(3)O(4) nanoparticles, desorption solvent and desroption time, were optimized. Under the optimum conditions, the recoveries of analytes done on samples spiked with the target analytes were between 96.4% and 108.6%; relative standard deviations ranged from 0.6% to 8.7%. The correlation coefficients varied from 0.9917 to 0.9988. The limits of detection ranged from 5.4 to 16.8 ng mL(-1) at a signal-to-noise ratio of 3. All four different brands of green tea beverage samples were successfully analyzed by the proposed method.     

Separation and preconcentration of trace amounts of gold(III) ions using modified multiwalled carbon nanotube sorbent prior to flame atomic absorption spectrometry determination

Multiwalled carbon nanotubes are attractive as sorbents for SPE because they can be used for enrichment of organic compounds and metal ions at trace levels. In this study, multiwalled carbon nanotubes were oxidized with concentrated HNO3, and then the oxidized multiwalled carbon nanotubes were modified with 5-(4'-dimethylamino-benzyliden)-rhodanine. The modified multiwalled carbon nanotubes were used as a solid sorbent for separation and preconcentration of trace amounts of Au(III) ions. The sorption of Au(III) ions was quantitative in the pH range of 2.0-5.0, whereas quantitative desorption occurred instantaneously with 5.0 mL 2.0 M Na2S2O3. The eluted solution was aspirated directly into the flame for atomic absorption spectrometry. The proposed method resulted in an enrichment factor of 94. The RSD of the method was +/- 1.11% (n=10, 2.0 microg/mL) and the LOD was 0.15 ng/mL. The calibration curve for Au(III) was linear between 0.53 ng/mL and 36.0 microg/mL in the initial solution, with an R2 value of 0.9999. The sorbent capacity of the modified multiwalled carbon nanotubes was 7.3 mg Au(III)/g sorbent. The influences of the experimental parameters, including sample pH, sample flow rate, eluent volume and flow rate, sample volume, and interference of some ions on the recoveries of the Au ions, were investigated. The proposed method was applied for preconcentration and determination of Au in different samples.     

Evaluation of carbon nanotubes as a solid-phase extraction adsorbent for the extraction of cephalosporins antibiotics, sulfonamides and phenolic compounds from aqueous solution

The adsorptive potential of carbon nanotubes (single-walled carbon nanotubes and multi-walled carbon nanotubes) for solid-phase extraction of three groups of highly polar compounds (namely cephalosporins antibiotics, sulfonamides and phenolic compounds) was tested in this article. The analytes were strongly retained by the carbon nanotubes. And acceptable recoveries were obtained with the addition of ammonium acetate into eluents. The effects of solution pH on the recoveries of the antibiotics and phenolic compounds were examined. To check the retention abilities of three groups of compounds on carbon nanotubes, fixed amount of each analyte was added to different volumes (up to 500 mL) of aqueous solution, and then extracted by the sorbents. Comparative studies showed that the carbon nanotubes were much superior to C₁₈ for the extraction of the highly polar analytes. For the cephalosporins antibiotics and sulfonamides, the carbon nanotubes showed stronger retention capability than graphitized carbon blacks, but for some of the phenolic compounds graphitized carbon blacks seemed to be more suitable, indicating different retention mechanisms of these analytes. To further assess the enrichment ability of carbon nanotubes for highly polar compounds, the solid-phase extraction method of multi-walled carbon nanotubes packed cartridge was well developed, and the sulfonamides were used as model compounds. Under the optimal procedures, the detection limits of sulfonamides were in the range of 27-38 ng L⁻¹. The spiked recoveries from several real water samples obtained for sulfathiazole and sulfadiazine ranged from 55% to 79% and 72% to 92%, respectively, while the recoveries of sulfapyridine and sulfamethazine were in the range of 85-102%.     

Ionic liquid mediated sol-gel sorbents for hollow fiber solid-phase microextraction of pesticide residues in water and hair samples

An ionic liquid mediated sol-gel sorbents for hollow fiber solid-phase microextraction (HF-SPME) was developed for extraction of the pesticides: diazinon, fenitrothion, malathion, fenvalerate, phosalone and tridemorph from human hair and water samples. The analytes were subsequently analyzed with high performance liquid chromatography and diode array detection (HPLC-DAD). Preliminary experiments were carried out in order to study experimental conditions for pesticides' extraction from spiked hair and water samples with HF-SPME using hollow fiber-supported ionic liquid mediated sol-gel sorbent. The sol-gel nanocomposites were reinforced with nanoparticles such as carboxylic functionalized multi-walled carbon nanotubes (COOH-MWCNTs), amino functionalized multi-walled carbon nanotubes (NH(2)-MWCNTs), nano SiO(2), nano TiO(2) and nano MgO comparatively to promote extraction efficiency. In this device, the innovative solid sorbents were developed by the sol-gel method via the reaction of tetraethylorthosilicate (TEOS) with 2-amino-2-hydroxymethyl-propane-1,3-diol (TRIS). In the basic condition (pH 10-11), the gel growth process in the presence of ionic liquid and nanoparticles was initiated. Then, the sol was injected into a polypropylene hollow fiber segment for in situ gelation process. Parameters affecting the efficiency of HF-SPME were thoroughly investigated. Linearity was observed over a range of 0.01-25,000 ng/mL with detection limits between 0.004 and 0.095 ng/mL for the pesticides in the aqueous matrices and 0.003-0.080 ng/mL in the hair matrices. The relative recoveries in the real samples ranged from 82.0% to 94.0% for the pesticides store seller's hair and the work researchers' hair. Results are showing the great possibilities of HF-SPME-HPLC-PDA for analysis of pesticides in biological and environmental samples.     

Application of polyaniline–multiwalled carbon nanotubes composite fiber for determination of benzaldehyde in injectable pharmaceutical formulations by solid-phase microextraction GC–FID using experimental design

A polyaniline–multiwalled carbon nanotubes composite fiber was electrodeposited onto a platinum wire using cyclic voltammetry. This fiber was used for headspace solid-phase microextraction combined with gas chromatography and flame ionization detector of trace levels of benzaldehyde in some injectable pharmaceutical formulations. Three solid-phase microextraction parameters including temperature, time and stirring rate were investigated simultaneously using a three-level-three-factor Box–Behnken as experimental design on the extraction capability. The as-made fiber has a lifetime of over 300 extractions without any obvious decline in extraction efficiency. At the optimum conditions (extraction temperature 60°C, extraction time 15 min, stirring rate 700 rpm), the method displays excellent linearity over the concentration range of 25–1000 ng/mL of benzaldehyde with RSD values ranging from 1.0 to 6.8%. The limits of quantitation and detection were 25 and 10 ng/mL, respectively.     

Application of NaClO-treated multiwalled carbon nanotubes as solid phase extraction sorbents for preconcentration of trace 2,4-dichlorophenoxyacetic acid in aqueous samples

Multiwalled carbon nanotubes functionalized by oxidation of original multiwalled carbon nanotubes with NaClO were prepared and their application as solid phase extraction sorbent for 2,4-dichlorophenoxyacetic acid (2,4-D) was investigated systemically, and a new method was developed for the determination of trace 2,4-D in water samples based on extraction and preconcentration of 2,4-D with solid phase extraction columns packed with NaClO-treated multiwalled carbon nanotubes prior to its determination by HPLC. The optimum experimental parameters for preconcentration of 2,4-D, including the column activating conditions, the amount of the sorbent, pH of the sample, elution composition, and elution volume, were investigated. The results indicated 2,4-D could be quantitatively retained by 100 mg NaClO-treated multiwalled carbon nanotubes at pH 5, and then eluted completely with 10 mL 3:1 (v/v) methanol-ammonium acetate solution (0.3 mol/L). The detection limit of this method for 2,4-D was 0.15 μg/L, and the relative standard deviation was 2.3% for fortified tap water samples and 2.5% for fortified riverine water sample at the 10 μg/L level. The method was validated using fortified tap water and riverine water samples with known amount of 2,4-D at the 0.4, 10, and 30 μg/L levels, respectively.     

Determination of antidepressants in human urine extracted by magnetic multiwalled carbon nanotube poly(styrene‐co‐divinylbenzene) composites and separation by capillary electrophoresis

Poly(styrene‐co‐divinylbenzene)‐coated magnetic multiwalled carbon nanotube composite synthesized by in‐situ high temperature combination and precipitation polymerization of styrene‐co‐divinylbenzene has been employed as a magnetic sorbent for the solid phase extraction of antidepressants in human urine samples. Fluoxetine, venlafaxine, citalopram and sertraline were, afterwards, separated and determined by capillary electrophoresis with diode array detection. The presence of magnetic multiwalled carbon nanotubes in native poly(styrene‐co‐divinylbenzene) not only simplified sample treatment but also enhanced the adsorption efficiencies, obtaining extraction recoveries higher than 89.5% for all analytes. Moreover, this composite can be re‐used at least ten times without loss of efficiency and limits of detection ranging from 0.014 to 0.041 μg/mL were calculated. Additionally, precision values ranging from 0.08 to 7.50% and from 0.21 to 3.05% were obtained for the responses and for the migration times of the analytes, respectively.     

多壁纳米碳管固相萃取测定水中的有机氯农药

对于水样中的有机氯农药的净化方法主要是采用传统的液液分配的方法,缺点是溶剂使用量和前处理复杂。近年来固相萃取及固相微萃取等技术被应用到水样中的有机污染物的测定。如利用键合在硅胶上的非极性(C18,LC18等)或极性物质(LC-CN,LC-NH2)对水中有机物进行富集,用GDX或XAD自填的固相柱的报道也很多。纳米技术和纳米材料的发展为开发固相萃取材料带来新契机。纳米材料是指尺寸大小在从1～100m之间物质。与普通的块体材料相比,纳米材料具有较大的比表面,因而有可能具有较大吸附容量。纳米材料在环境有机污染物分离富集方面的应用研究才刚刚开始。本文主要就纳米碳管对水样中的有机氯农药进行研究,优化固相萃取条件。     

Solid‐phase extraction using bis(indolyl)methane‐modified silica reinforced with multiwalled carbon nanotubes for the simultaneous determination of flavonoids and aromatic organic acid preservatives

A novel bis(indolyl)methane‐modified silica reinforced with multiwalled carbon nanotubes sorbent for solid‐phase extraction was designed and synthesized by chemical immobilization of nitro‐substituted 3,3′‐bis(indolyl)methane on silica modified with multiwalled carbon nanotubes. Coupled with high‐performance liquid chromatography analysis, the extraction properties of the sorbent were evaluated for flavonoids and aromatic organic acid compounds. Under optimum conditions, the sorbent can simultaneously extract five flavonoids and two aromatic organic acid preservatives in aqueous solutions in a single‐step solid‐phase extraction procedure. Wide linear ranges were obtained with correlation coefficients (R²) ranging from 0.9843 to 0.9976, and the limits of detection were in the range of 0.5–5 μg/L for the compounds tested. Compared with the silica modified with multiwalled carbon nanotubes sorbent and the nitro‐substituted 3,3′‐bis(indolyl)methane‐modified silica sorbent, the developed sorbent exhibited higher extraction efficiency toward the selected analytes. The synergistic effect of nitro‐substituted 3,3′‐bis(indolyl)methane and multiwalled carbon nanotubes not only improved the surface‐to‐volume ratio but also enhanced multiple intermolecular interactions, such as hydrogen bonds, π–π, and hydrophobic interactions, between the new sorbent and the selected analytes. The as‐established solid‐phase extraction with high‐performance liquid chromatography and diode array detection method was successfully applied to the simultaneous determination of flavonoids and aromatic organic acid preservatives in grape juices with recoveries ranging from 83.9 to 112% for all the selected analytes.     

Multiwalled‐carbon‐nanotubes‐based matrix solid‐phase dispersion extraction coupled with high‐performance liquid chromatography for the determination of honokiol and magnolol in Magnoliae Cortex

In this paper, multiwalled‐carbon‐nanotube‐based matrix solid‐phase dispersion coupled to HPLC with diode array detection was used to extract and determine honokiol and magnolol from Magnoliae Cortex. The extraction efficiency of the multiwalled‐carbon‐nanotube‐based matrix solid‐phase dispersion was studied and optimized as a function of the amount of dispersing sorbent, volume of elution solvent, and flow rate of elution solvent, with the aid of response surface methodology. An amount of 0.06 g of carboxyl‐modified multiwalled carbon nanotubes and 1.5 mL of methanol at a flow rate of 1.1 mL/min were selected. The method obtained good linearity (r² > 0.9992) and precision (RSD < 4.7%) for honokiol and magnolol, with limits of detection of 0.045 and 0.087 μg/mL, respectively. The recoveries obtained from analyzing in triplicate spiked samples were determined to be from 90.23 to 101.10% and the RSDs from 3.5 to 4.8%. The proposed method that required less samples and reagents was simpler and faster than Soxhlet and maceration extraction methods. The optimized method was applied for analyzing five real samples collected from different cultivated areas.     

Rapid and sensitive detection of the phenoxy acid herbicides in environmental water samples by magnetic solid‐phase extraction combined with liquid chromatography–tandem mass spectrometry

Phenoxy acid herbicides are widely used herbicides that play an important role in improving the yield and quality of crops. However, some research has shown that this kind of herbicide is poisonous to human and animals. In this study, a rapid and sensitive method was developed for the detection of seven phenoxy acid herbicides in water samples based on magnetic solid‐phase extraction followed by liquid chromatography and tandem mass spectrometry. Magnetic amino‐functionalized multiwalled carbon nanotubes were prepared by mixing bare magnetic Fe₃O₄ nanoparticles with commercial amino‐functionalized multiwalled carbon nanotubes in water. Then the amino‐functionalized multiwalled carbon nanotubes were used to enrich phenoxy acid herbicides from water samples based on hydrophobic and ionic interactions. The effects of experimental variables on the extraction efficiency have been studied in detail. Under the optimized conditions, the method validation was performed. Good linearities for seven phenoxy acid herbicides were obtained with squared regression coefficients ranging from 0.9971 to 0.9989. The limits of detection ranged from 0.01 to 0.02 μg/L. The method recoveries of seven phenoxy acid herbicides spiked at three concentration levels in a blank sample were from 92.3 to 103.2%, with inter‐ and intraday relative standard deviations less than 12.6%.     

Polyelectrolyte functionalized multi-walled carbon nanotubes as strong anion-exchange material for the extraction of acidic degradation products of nerve agents

Extraction, enrichment and gas chromatography mass spectrometric analysis of degradation products of nerve agents from water is of significant importance for verification of Chemical Weapons Convention (CWC) and gathering forensic evidence of use of nerve agents. Multi-walled carbon nanotubes (MWCNTs) were non-covalently functionalized with poly(diallyldimethylammonium chloride) (PDDA) to afford the cationic functionalized nano-tubes, which were used as solid-phase anionic-exchanger sorbents to extract the acidic degradation products of nerve agents from water. Extraction efficiencies of MWCNTs-PDDA were compared with those of mixed mode anion-exchange (HLB) and silica based strong anion-exchange (Si-SAX) cartridges. Optimized extraction parameters included MWCNTs-PDDA 12 mg, washing solvent 5 mL water and eluting solvent 3 mL of 0.1M aqueous HCl followed by 3 mL methanol. At 1 ng mL(-1) spiking concentration of mono- and di-basic phosphonic acids, MWCNTs-PDDA exhibited higher extraction efficiencies in comparison to Si-SAX and HLB. The limits of detection were achieved down to 0.05 and 0.11 ng mL(-1) in selected ion and full scan monitoring mode respectively; and limits of quantification in selected ion monitoring mode were achieved down to 0.21 ng mL(-1).     

Solid‐phase microextraction based on an agarose‐chitosan‐multiwalled carbon nanotube composite film combined with HPLC–UV for the determination of nonsteroidal anti‐inflammatory drugs in aqueous samples

We describe the preparation, characterization, and application of a composite film adsorbent based on blended agarose‐chitosan‐multiwalled carbon nanotubes for the preconcentration of selected nonsteroidal anti‐inflammatory drugs in aqueous samples before determination by high performance liquid chromatography with ultraviolet detection. The composite film showed a high surface area (4.0258 m²/g) and strong hydrogen bonding between the multiwalled carbon nanotubes and agarose/chitosan matrix, which prevent adsorbent deactivation and ensure long‐term stability. Several parameters, such as sample pH, addition of salt, extraction time, desorption solvent, and concentration of multiwalled carbon nanotubes in the composite film were optimized using a one‐factor‐at‐time approach. The optimum extraction conditions obtained were as follows: isopropanol as conditioning solvent, 10 mL of sample solution at pH 2, extraction time of 30 min, stirring speed of 600 rpm, 100 μL of isopropanol as desorption solvent, desorption time of 5 min under ultrasonication, and 0.4% w/v of composite film. Under the optimized conditions, the calibration curve showed good linearity in the range of 1–500 ng/mL (r² = 0.997–0.999), and good limits of detection (0.89–8.05 ng/mL) were obtained with good relative standard deviations of < 4.59% (n = 3) for the determination of naproxen, diclofenac sodium salt, and mefenamic acid drugs.