Effective extraction and simultaneous determination of Sudan dyes from tomato sauce and chili‐containing foods using magnetite/reduced graphene oxide nanoparticles coupled with high‐performance liquid chromatography

A simple, effective, and robust magnetic solid‐phase extraction method was developed using magnetite/reduced graphene oxide nanoparticles as the adsorbent for the simultaneous determination of Sudan dyes (I, II, III, and IV) in foodstuffs. The magnetite/reduced graphene oxide nanoparticles were characterized by X‐ray diffraction, scanning electron microscopy, and vibrating sample magnetometry. The extraction parameters including extraction time, elution solution, and elution time and volume were investigated in detail. Such magnetite/reduced graphene oxide nanoparticles based magnetic solid‐phase extraction in combination with high‐performance liquid chromatography and variable wavelength detection gave the detection limits of 3–6 μg/kg for Sudan I–IV in chili sauce, tomato sauce, chili powder, and chili flake samples. The recoveries were 79.6–108% at three spiked levels with the intra‐ and inter‐day relative standard deviations of 1.2–8.6 and 4.5–9.6%, respectively. The feasibility was further performed by a comparison with commercial alumina‐N. This method is suitable for the routine analysis of Sudan dyes due to its sensitivity, simplicity, and low cost.     

Enantioselective determination of acaricide etoxazole in orange pulp,peel, and whole orange by chiral liquid chromatography with tandem mass spectrometry

An efficient enantioselective method for the determination of etoxazole in orange pulp, peel, and whole orange was developed using liquid chromatography with tandem mass spectrometry. The enantioseparation was performed on a Chiralpak AD‐3R column at 30ºC using acetonitrile with 0.1% formic acid solution (80:20, v/v) as the mobile phase in less than 5 min. Quantification was achieved using matrix‐matched standard calibration curves. The overall mean recoveries for two enantiomers from orange pulp and whole orange were 91.0–99.6% and the orange peel was 92.6–103.1%, with relative standard deviations of 0.8–5.4% intraday and 2.0–4.8% interday at 1, 10, and 100 μg/kg levels, and 1.3–5.2% intraday and 3.5–4.3% interday at 5, 50, and 500 μg/kg levels, respectively. The limits of quantification for all enantiomers in three matrices did not exceed 5 μg/kg. Moreover, the absolute configuration of etoxazole enantiomers had been determined by the combination of experimental and predicted electronic circular dichroism spectra, and the first eluted enantiomer was confirmed as (S)‐etoxazole on a Chiralpak AD‐3R column while (R)‐etoxazole was first on three cellulose chiral columns. The application of the proposed method to real sample analysis suggests its potential use in enantioselective determination of etoxazole enantiomers in citrus.     

Matrix Solid-Phase Dispersion Extraction and UPLC Determination of Sudan Dyes in Chili Powder

A new method involving matrix solid-phase dispersion (MSPD) extraction and UPLC in conjunction with photodiode array detection was developed for the rapid and simple determination of Sudan dyes in chili powder. Separation of Sudan I, Sudan II, Sudan III, and Sudan IV was achieved within 2 min on the 1.7 μm Acquity UPLC BEH C18 column by using gradient elution with a mobile phase consisting of acetonitrile–water at a flow rate of 0.5 mL min^?1. Optimization of MSPD extraction parameters, such as type of solid sorbent and elution solvent were carried out. Optimal conditions selected for MSPD extraction were 0.25 g of sample, 0.5 g of silica gel as solid sorbent, and 7 mL of acetonitrile–methanol (9:1, v/v) as eluting solvent. Limits of detection ranged between 0.25 and 0.30 mg kg^?1 depending on the dye involved. All analytes provided average recoveries from spiked (at 1, 1.5, and 2 mg kg^?1) chili powder samples ranging from 81 to 106%. The method was applied to the analysis of chili powder samples obtained from different countries.     

Development of a γ‐alumina‐ nanoparticle‐functionalized porous polymer monolith for the enrichment of Sudan dyes in red wine samples

Monolithic materials were synthesized in capillaries by in situ polymerization with N‐isopropylacrylamide, glycidyl methacrylate, and ethylene dimethacrylate as the monomers, and methanol and PEG as the porogens. With γ‐alumina nanoparticles attached to the surface of the porous monolithic column via epoxide groups, a novel polymer monolith microextraction (PMME) material was prepared with a good mechanical stability and a high extraction capacity. SEM and X‐ray photoelectron spectroscopy were employed to characterize the modified monolithic column, demonstrating that γ‐alumina nanoparticles were effectively functionalized onto the monolithic column. In addition, a new method was developed for the analysis of Sudan I–IV dyes using PMME coupled with HPLC. In order to obtain the optimum extraction efficiency, the PMME conditions including desorption solvent type, sample pH, sample volume, sample flow rate, and eluent flow rate were investigated. Under the optimum conditions, we obtained acceptable linearities, low LODs, and good intra‐ and interday RDSs. When applied to the determination of Sudan I–IV dyes in red wine samples, satisfactory recoveries were obtained in the range of 84.0–115.9%.     

Enantioselective determination of carboxyl acid amide fungicide mandipropamid in vegetables and fruits by chiral LC coupled with MS/MS

An efficient enantioselective method for the determination of mandipropamid in vegetables and fruits was presented by LC coupled with MS/MS. The mandipropamid residues in samples (potato, pepper, grape, and watermelon) were extracted with acetonitrile containing 1% acetic acid. An aliquot was cleaned up with primary and secondary amine and C₁₈ sorbent. Complete enantioseparation of mandipropamid enantiomers in <4 min was obtained on a Lux Cellulose‐2 column at 25°C using methanol with 0.1% formic acid/0.1% aqueous formic acid solution (85:15, v/v) as mobile phase. Good linearity was obtained over the concentration range of 0.5–250 μg/L for each enantiomer in the standard solution and sample matrix calibration curves. Quantification was achieved using matrix‐matched standard calibration curves. The interday mean recoveries, intraday repeatability, and inter‐day reproducibility varied from 76.4 to 97.1%, 3.4 to 9.4%, and 3.5 to 11.4%, respectively. The limits of quantification for mandipropamid enantiomers in vegetables and fruits were both 1 μg/kg. Moreover, the absolute configuration of mandipropamid enantiomers was determined by the combination of experimental and predicted electronic circular dichroism spectra, and the first eluted enantiomer was confirmed as (R)‐mandipropamid on five chiral columns.     

Rapid determination of nosiheptide in feed based on dispersive SPE coupled with HPLC

A novel, simple, and reliable method based on high‐performance liquid chromatography coupled with fluorescence detection has been developed for the determination of nosiheptide in feed. The feed samples were extracted with acetonitrile 0.1% formic acid aqueous solution and then purified via a dispersive solid‐phase extraction procedure using silica gel powder as the sorbent. Using a mixture of acetonitrile and 5 mM ammonium acetate solution (containing 0.1% formic acid) as the mobile phase, good separation and peak shape were obtained for nosiheptide on a Poroshell C₈ column (250 × 4.6 mm id, 4 μm) via the isocratic elution program. The resulting calibration curve shows high levels of linearity (r² > 0.999) for nosiheptide concentrations of 50–1000 μg/L. At three spiked levels, i.e., 0.500, 2.50 and 5.00 mg/kg, the intra‐ and interday recoveries of nosiheptide in five types of feed ranged from 78.5–96.8 and 84.9–94.2%, respectively. The intra‐ and interday relative standard deviations were less than 10.8%. The limits of quantification for nosiheptide in complete feed and premixes were measured as 50 and 100 μg/kg, respectively. Compared with other common adsorbents, silica gel presents stronger recovery and purification results for feed samples during the dispersive solid‐phase extraction process.     

Fabrication of single‐walled carbon nanohorns incorporated a monolithic column for capillary electrochromatography

Single‐walled carbon nanohorns have received great interest for their unique properties and diverse potential applications. Herein, we demonstrated the feasibility of single‐walled carbon nanohorns incorporated poly(styrene‐divinylbenzene) monolith as the stationary phase for capillary electrochromatography, which were prepared by one‐step in situ copolymerization. Single‐walled carbon nanohorns were dispersed in styrene to give a stable and homogeneous suspension. The monolithic column gave effective separation for a wide range of aromatic compounds, which was based on hydrophobicity and π–π electrostatic stacking of single‐walled carbon nanohorns. The precisions of migration time and peak area varied in the ranges of 1.4–1.9% for intraday trials and 1.7–3.5% for interday trials, and 3.2–6.7% for intraday trials and 4.1–7.4% for interday trials, and 3.6–7.2% for inter‐column trials and 5.2–21.3% for inter‐column trials, respectively, indicating the good reproducibility of single‐walled carbon nanohorns embedded monolithic columns.     

Matrix Solid-Phase Dispersion Extraction and UPLC Determination of Sudan Dyes in Chili Powder

A new method involving matrix solid-phase dispersion (MSPD) extraction and UPLC in conjunction with photodiode array detection was developed for the rapid and simple determination of Sudan dyes in chili powder. Separation of Sudan I, Sudan II, Sudan III, and Sudan IV was achieved within 2 min on the 1.7 μm Acquity UPLC BEH C18 column by using gradient elution with a mobile phase consisting of acetonitrile–water at a flow rate of 0.5 mL min⁻¹. Optimization of MSPD extraction parameters, such as type of solid sorbent and elution solvent were carried out. Optimal conditions selected for MSPD extraction were 0.25 g of sample, 0.5 g of silica gel as solid sorbent, and 7 mL of acetonitrile–methanol (9:1, v/v) as eluting solvent. Limits of detection ranged between 0.25 and 0.30 mg kg⁻¹ depending on the dye involved. All analytes provided average recoveries from spiked (at 1, 1.5, and 2 mg kg⁻¹) chili powder samples ranging from 81 to 106%. The method was applied to the analysis of chili powder samples obtained from different countries.

     

New approach applying a pet fish air pump in liquid‐phase microextraction for the determination of Sudan dyes in food samples by HPLC

A new approach applying a pet fish air pump is introduced to develop an extraction method, namely, air‐pump‐enhanced emulsion, followed by salt‐assisted emulsion breaking based on solidified floating organic drop microextraction for the extraction and preconcentration of Sudan I–IV before high‐performance liquid chromatography. The applicability of this method was successfully demonstrated by determination of these dyes in four chili products that include chili powder, chili oil, chili sauce, and chili paste. An enrichment factor of 62 was obtained only with a sample solution of 5 mL. A linear range of 0.5–2500 ng/mL was obtained with a limit of detection of 0.16–0.24 ng/mL and recovery of 90–110%. This method is superior to other liquid–liquid extraction methods, as is simple, rapid, environmental friendly, and its phase separation needs no centrifugation. It also needs no disperser solvent and requires less organic solvent, and satisfies the criteria to be called as a green extraction. Therefore, this facile extraction method can be successfully applied in the determination of Sudan dyes in food samples.     

Preparation of monolithic fibers for the solid‐phase microextraction of chlorophenols in water samples

Monolithic fibers were synthesized and applied for the solid‐phase microextraction and determination of chlorophenols in environmental water samples by coupling with HPLC. The fibers were prepared by copolymerization of vinylimidazole and ethylene dimethacrylate as functional monomer and cross‐linker, respectively. The effect of the preparation conditions of monolithic fibers on the extraction efficiencies was investigated in detail. Several characteristic techniques, such as elemental analysis, infrared spectroscopy, mercury‐intrusion porosimetry, and SEM were used to characterize the monolithic material. The effect of the extraction parameters, including desorption solvent, extraction and desorption time, pH values, and ionic strength in sample matrix on the extraction performance was investigated thoroughly. Under the improved extraction conditions, the linear ranges of 2‐chlorophenol, 2,4‐dichlorophenol and pentachlorophenol were 1.0–200 μg/L and 2.0–200 μg/L for 2,4,6‐trichlorophenol. The detection limits (S/N = 3) were in the range of 0.16–0.45 μg/L, the RSDs for intraday and interday precisions were <7.0%. Finally, the proposed method was successfully used to detect different environmental water samples. The recoveries of spiked water samples were ranged from 90.0 to 115%. At the same time, satisfactory repeatability was achieved with RSDs < 9.0%.     

Determination of 3-hydroxy pterocarpan, a novel osteogenic compound in rat plasma by liquid chromatography-tandem mass spectrometry: application to pharmacokinetics study

A rapid, sensitive and selective LC‐MS/MS method for the quantitative analysis of 3‐hydroxy pterocarpan (S006‐1709) in female rat plasma has been developed and validated. A Discovery RP₁₈ column was used for the chromatographic elution using acetonitrile and 0.1% acetic acid in water as mobile phase (80:20 v/v) at the flow rate of 0.5 mL/min. MS/MS analysis was performed using a triple quadrupole mass spectrometer with electrospray ionization in negative ion mode using biochanin as an internal standard (IS). Extraction of S006‐1709 and IS from rat plasma was done by liquid–liquid extraction method using diethyl ether. The LC‐MS/MS method was sensitive with 1.95 ng/mL as the limit of detection and 3.9 ng/mL as the lower limit of quantification. The method was linear in the concentration range of 3.9–1000 ng/mL. The percentage bias for intraday and interday accuracy was not greater than 4.2 and the %RSD for intraday and interday precision was not greater than 13.2. The recoveries of S006‐1709 and IS were 73.9–79.3 and 85.7%, respectively. S006‐1709 was found to be stable in various stability studies. The validated LC‐MS/MS method was successfully applied for the oral pharmacokinetics study of S006‐1709 at 10 mg/kg in female Sprague–Dawley rats. Copyright © 2010 John Wiley & Sons, Ltd.     

Multilayered particle‐packed column: Evaluation and comparison with monolithic and core–shell particle columns for the determination of red azo dyes in Sequential Injection Chromatography

A recently presented new type of “multilayered” organic–inorganic hybrid silica particle packed column YMC‐Triart C₁₈ (50 mm × 4.6 mm, 5 μm) was used for the development of a sequential injection chromatography method for determination of five azo dyes (Sudan I, Sudan II, Sudan III, Sudan orange G, and para red) in selected food seasonings. The use of a novel sorbent brings attractive features, reduced backpressure, and broader chemical stability together with high separation performance, which are discussed and compared with that of three types of columns typically used in medium‐pressure flow chromatography techniques (classic monolithic, narrow monolithic, and core–shell particle columns). The separation was performed in gradient elution mode created by the zone mixing of two mobile phases (acetonitrile/water 90:10, 1.5 mL + acetonitrile/water 100:0, 2.3 mL) at a flow rate of 0.60 mL/min and time of analysis <9.5 min. The spectrophotometric detection wavelengths were set to 400, 480, and 500 nm. The high performance of the developed method with multilayered particle column was well documented and the results indicate a broad capability of sequential injection chromatography.     

Determination of azithromycin residue in pork using a molecularly imprinted monolithic microcolumn coupled to liquid chromatography with tandem mass spectrometry

Using spiramycin as a dummy template, a molecularly imprinted polymer monolithic micro‐column with high selection to azithromycin was prepared in a micropipette tip. The imprinting factor of the monolithic micro‐column prepared was approximately 2.67 and the morphological structure of the polymers was characterized by scanning electron microscopy. A simple, sensitive, and reproducible method based on the imprinted monolithic micro‐column coupled to liquid chromatography with tandem mass spectrometry was developed for determining the residues of azithromycin in pork. Pork samples were extracted with acetonitrile, cleaned up under the optimal monolithic micro‐column conditions, and analyzed using liquid chromatography with tandem mass spectrometry in the multiple reaction monitoring mode. The assay exhibited a linear dynamic range of 0.50–50 μg/L with the correlation coefficient (r²) above 0.99. In the three spiking levels of 0.50, 1.0, and 10 μg/kg, the average recoveries of azithromycin from pork samples were between 85.8 and 96.5% with a relative standard deviation below 10%. The limit of detection and limit of quantitation were 0.03 and 0.1 μg/kg, respectively.     

A high‐throughput screening method for determination of multi‐antibiotics in animal feed

A high‐throughput method based on ultrasonic‐assisted extraction, 96‐well plate thin‐film microextraction was established to determinate 18 antibiotics in animal feed. In this method, the extraction was implemented by ultrasonic‐assisted extraction for 30 min with disodium ethylenediaminetetraacetic acid‐McIlvaine buffer (pH 5) containing 6% sodium chloride w/v, purified by thin‐film microextraction and combined with 96‐well plate system to improve the efficiency. Optimization of thin‐film microextraction conditions was performed by methods of single factor and response surface, and finalized as: condition time: 20 min; adsorption time: 55 min; washing time: 5 s with water; desorption time: 30 min with acetonitrile/water (8:2, v/v) containing 0.1% formic acid v/v. Evaluation of different extractive phases showed that polystyrene‐divinylbenzene‐polyacrylonitrile was the optimum coating. The analysis was performed by ultra‐high performance liquid chromatography with tandem mass spectrometry. Recovery, inter‐ and intraday precision, linearity, limit of detection, and quantitation were evaluated. The average recoveries of 18 antibiotics were 66.6–93.5% at three spiked levels, intraday precision was 1–8.4%, and interday precision was 3.0–16.4%. The linearity was good for r² > 0.99. Limits of detection and quantification were found in the range of 1–14 and 4–48 µg/kg, respectively.     

Preparation of an acryloyl β‐cyclodextrin‐silica hybrid monolithic column and its application in pipette tip solid‐phase extraction and HPLC analysis of methyl parathion and fenthion

An acryloyl β‐cyclodextrin‐silica hybrid monolithic column for pipette tip solid‐phase extraction and high‐performance liquid chromatography determination of methyl parathion and fenthion has been prepared through a sol–gel polymerization method. The synthesis conditions, including the volume of cross‐linker and the ratio of inorganic solution to organic solution, were optimized. The prepared monolithic column was characterized by thermogravimetric analysis, scanning electron microscopy, and Fourier transform infrared spectroscopy. The eluent type, volume and flow rate, sample volume, flow rate, acidity, and ionic strength were optimized in detail. Under the optimized conditions, a simple and sensitive pipette tip solid‐phase extraction with high‐performance liquid chromatography method was developed for the determination of methyl parathion and fenthion in lettuce. The method yielded a linear calibration curve in the concentration ranges of 15–400 μg/kg for methyl parathion and 20–400 μg/kg for fenthion with correlation coefficients of above 0.9957. The limits of detection were 4.5 μg/kg for methyl parathion and 6.0 μg/kg for fenthion, respectively. The recoveries of methyl parathion and fenthion spiked in lettuce ranged from 96.0 to 104.2% with relative standard deviations less than 8.4%.     

A natural and renewable biosorbent phase as a low‐cost approach in disposable pipette extraction technique for the determination of emerging contaminants in lake water samples

This study proposes an efficient analytical methodology using a biosorbent (cork) as an extraction phase in disposable pipette extraction technique for the rapid determination of the emerging contaminants methyl paraben, ethyl paraben, benzophenone, 3‐(4‐methylbenzylidene) camphor and 2‐(ethylhexyl)‐4‐(dimethylamino) benzoate in lake water samples using high‐performance liquid chromatography with diode array detection. The optimized conditions were comprised of 800 μL of sample, three cycles of 30 s each for the extraction, pH 6, addition of 30% w/v of NaCl. For the desorption step, the optimized desorption conditions were achieved with 100 μL of a mixture comprised of 50% methanol and 50% acetonitrile v/v, using one cycle of 30 s. Excellent analytical performance was achieved with limits of detection of 0.6 μg/L for methyl paraben to 1.4 μg/L for 3‐(4‐methylbenzylidene) camphor, and the limit of quantitation varied from 2 μg/L for methyl paraben to 4.3 μg/L 3‐(4‐methylbenzylidene) camphor, respectively. The correlation coefficients ranged from 0.9962 for ethyl paraben to 0.9980 for methyl paraben. The method accuracy varied from 71–132%, and the intraday precision ranged from 3 to 23% (n = 3) and interday from 9 to 23% (n = 9). The robustness was evaluated through Youden and Lenth's methods and indicated no significant variations in the results.     

Magnetic solid‐phase extraction and ultrafast liquid chromatographic detection of Sudan dyes in red wines,juices, and mature vinegars

A nanocomposite of polystyrene‐coated magnetic nanoparticles was successfully synthesized and employed as adsorbent for magnetic solid‐phase extraction of four Sudan dyes (I, II III, and IV) in red wines, juices, and mature vinegars. The prepared magnetic nanoparticles with highly hydrophobic properties have excellent adsorption capacity for these lipophilic Sudan dyes. Extraction conditions were optimized. Experimental results showed that the recoveries of the four Sudan dyes were very satisfactory when 70 mg of polystyrene‐coated magnetic nanoparticles were used and the extraction could be completed within 20 min. It was proved that these magnetic nanoparticles can be reused after an easy washing process. By coupling the magnetic solid‐phase extraction with ultrafast liquid chromatography‐ultraviolet spectrometry, a rapid, green, effective, and sensitive method for the determination of Sudan dyes was developed. The LOD for Sudan I, Sudan II, Sudan III, and Sudan IV were 0.0039, 0.0063, 0.0057, and 0.017 ng/mL, respectively. Recoveries obtained by analyzing spiked water samples at three concentration levels (0.1, 1.0, and 10.0 ng/mL) were between 76.3 and 96.6%. The intra‐ and interday RSDs for the analytes were lower than 9.6%.     

Graphene‐coated magnetic‐sheet solid‐phase extraction followed by high‐performance liquid chromatography with fluorescence detection for the determination of aflatoxins B1, B2, G1, and G2 in soy‐based samples

A new method named graphene‐coated magnetic‐sheet solid‐phase extraction based on a magnetic three‐dimensional graphene sorbent was developed for the extraction of aflatoxins prior to high‐performance liquid chromatography with fluorescence detection. The use of a perforated magnetic‐sheet for fixing the magnetic nanoparticles is a new feature of the method. Hence, the adsorbent particles can be separated from sample solution without using an external magnetic field. This made the procedure very simple and easy to operate so that all steps of the extraction process (sample loading, washing, and desorption) were carried out continuously using two lab‐made syringe pumps. The factors affecting the performance of extraction procedure such as the extraction solvent, adsorbent dose, sample loading flow rate, ionic strength, pH, and desorption parameters were investigated and optimized. Under the optimal conditions, the obtained enrichment factors and limits of detection were in the range of 205–236 and 0.09–0.15 μg/kg, respectively. The relative standard deviations were <3.4 and 7.5% for the intraday (n = 6) and interday (n = 4) precisions, respectively. The developed method was successfully applied to determine aflatoxins B₁, B₂, G₁, and G₂ in different soy‐based food samples.     

Determination of three kinds of banned drugs in milk powder by hybrid solid‐phase extraction purification combined with gas chromatography and mass spectrometry

A gradient clean‐up method for the quantification of five kinds of banned drugs (two hormones, two sedatives, and one chloramphenicol) in milk powder was developed. We used the combination of solid‐phase extraction purification with gas chromatography and mass spectrometry. Milk powder was initially hydrolyzed by β‐glucuronidase/arylsulfatase, and then the hydrolyzed solution was concentrated and purified using a C₈ and cation resin solid‐phase extraction column. To isolate hormones and chloramphenicol drugs, products from the previous step were diluted with methanol and further purified using a silica and diatomite solid‐phase extraction column. After derivatization, the drugs were analyzed by gas chromatography with mass spectrometry, and the hydrolyzed solution was diluted with 5% ammoniated methanol to purify sedatives before gas chromatography with mass spectrometry analysis. Results showed that after adding the banned drugs at concentrations of 0.3–10.0 μg/kg, the average recovery range was 78.2–97.3% with relative standard deviations of 5.3–12.5%. The limit of quantification of the banned drugs (S/N ≥ 10) was 0.3–5.0 μg/kg, whereas the limit of detection (S/N ≥ 3) was 0.1–2.0 μg/kg. The solid‐phase extraction gradient purification system was simple, rapid, and accurate, and could satisfy the detection requirements of hormone, sedatives, and chloramphenicol drugs when used together with gas chromatography and mass spectrometry.     

Sodium desoxycholate‐assisted capillary electrochromatography with methacrylate ester‐based monolithic column on fast separation and determination of coumarin analogs in Angelica dahurica extract

A rapid and sensitive CEC method with methacrylate ester‐based monolithic column has been developed for separation and determination of five coumarins (byakangelicin, oxypeucedanin hydrate, xanthotoxol, 5‐hydroxy‐8‐methoxypsoralen and bergapten) in Angelica dahurica extract. Surfactant sodium desoxycholate (SDC) was introduced into the mobile phase as the pseudostationary to dynamically increase the selectivity of analytes instead of increasing the hydrophobicity of stationary phase. In addition, other factors, pH of phosphate buffer, ACN content and applied voltage, for instance, have also an obvious effect on the resolution but little on the retention time. Satisfactory separation of these five coumarins was achieved within 6 min under a 30:70 v/v ACN–buffer containing 20 mM sodium dihydrogen phosphate (NaH₂PO₄) and 0.25 mM SDC at pH 2.51. The RSDs of intraday and interday for relative peak areas were less than 3.0% and 4.7%, respectively; and the recoveries were between 87.5% and 95.0%. The LODs were lower than 0.15 μg/mL and the LOQs were lower than 0.30 μg/mL, respectively, while calibration curves showed a good linearity (r² > 0.9979). Finally, five target coumarins from the crude extracts of A. dahurica were separated, purified, and concentrated by D‐101 macroporous resin, and were successfully separated and quantitatively determined within 6 min.