Determination of trans-fatty acids in food samples based on the precolumn fluorescence derivatization by high performance liquid chromatography

Trans-fatty acids are unsaturated fatty acids that are considered to have health risks. 1,3,5,7-Tetramethyl-8-butyrethylenediamine-difluoroboradiaza-s-indacene is a highly sensitive fluorescent labeling reagent for carboxylic acids developed by our lab. In this study, using this precolumn fluorescent derivatization reagent, a rapid and accurate high-performance liquid chromatography with fluorescence detection method was developed for the determination of two trans-fatty acids in food samples. Under the optimized derivative conditions, two trans-fatty acids were tagged with the fluorescent labeling reagent in the presence of 1-ethyl-3-(3-dimethyl-aminopropyl) carbodiimide at 25°C for 30 min. Then, the baseline separation of trans- and cis-fatty acids and their saturated fatty acid with similar structures was achieved with less interference using a reversed-phased C₁₈ column with isocratic elution in 14 min. With fluorescence detection at λ_ex/λ_em = 490 /510 nm, the linear range of the TFAs was 1.0-200 nM with low detection limits in the range of 0.1–0.2 nM (signal-to-noise ratio = 3). In addition, the proposed approach was successfully applied for the detection of trans-fatty acids in food samples, and the recoveries using this method ranged from 96.02 to 109.22% with low relative standard deviations of 1.2–4.3% (n = 6).     

Quantification of bisphenol A and its selected analogs in serum using pre‐column derivatization with high‐performance liquid chromatography and tandem mass spectrometry

Due to regulation of the use of bisphenol A, several analogs serving as bisphenol A replacements have drawn substantial attention for their adverse health effects. To investigate their occurrence in humans and identify possible pollution sources, it is necessary to develop a sensitive method for total bisphenols detection. Thus, a method based on enzymolysis and liquid‐liquid extraction followed by molecularly imprinted polymer solid‐phase extraction and pre‐column derivatization with high‐performance liquid chromatography and tandem mass spectrometry was proposed. The developed method exhibited superior selectivity and sensitivity. The matrix effect can be eliminated to a great extent. The method detection limits for eight bisphenols were 0.05～0.19 ng/mL. Satisfactory recoveries (71～119%) were obtained by spiking bovine serum at three levels (0.8, 8 and, 20 ng/mL). The method was successfully applied to determine total bisphenols in the serum samples of children. Bisphenol A, bisphenol F, bisphenol S, bisphenol B and bisphenol F were detected with concentrations from below the method detection limit to 1.65, 0.45, 0.79, 2.04 and 0.17 ng/mL, respectively. These results indicate that bisphenol A remains the major pollutant among the studied bisphenols in children, whereas threats from bisphenol A analogs should also be monitored.     

Enantiomeric separation of d‐ and l‐serine using high‐performance liquid chromatography with electrochemical detection following pre‐column diastereomer derivatization

Enantiomeric separation of d ‐ and l ‐serine on an octadecylsilica column was investigated using (2R)‐2,5‐dioxopyrrolidin‐1‐yl‐2,5,7,8‐tetramethyl‐6‐(tetrahydro‐2H‐pyran‐2‐yloxy)chroman‐2‐carboxylate (R‐NPCA), which was developed for a pre‐column derivatization reagent for electrochemical detection. In addition, (2S)‐2,5‐dioxopyrrolidin‐1‐yl‐2,5,7,8‐tetramethyl‐6‐(tetrahydro‐2H‐pyran‐2‐yloxy)chroman‐2‐carboxylate (S‐NPCA) was newly synthesized from (S)‐(?)‐6‐hydroxy‐2,5,7,8‐tetramethylchroman‐2‐carboxylic acid (S‐α‐CA), and the enantiomeric separation of d ‐ and l ‐serine using S‐NPCA was also examined. The enantiomeric separation of d ,l ‐serine was achieved using the R‐ or S‐NPCA as a chiral derivatization reagent, and the elution orders of the enantiomers were reversed between R‐ and S‐NPCA. The elution orders of d ‐ and l ‐serine unexpectedly reversed between the phosphate buffer at pH 4.0 and pH 2.2, both of which were used in the mobile phase. Separation factors obtained using R‐ and S‐NPCA were similar—1.09 and 1.07, respectively. The detection limit was approximately 940 fmol on the column (signal‐to‐noise ratio 3) when the applied voltage was +650 mV. Copyright © 2009 John Wiley & Sons, Ltd.     

The stable o‐phthalaldehyde‐ferrocene/6‐ferrocenyl‐1‐hexanethiol pre‐column derivatization high‐performance liquid chromatography of dimethylarginine by novel dual fluorescence and electrochemical detector

Monomethylarginine, asymmetric dimethylarginine and symmetric dimethylarginine were separated on a Wakopak Combi ODS with an acetonitrile–100 mm potassium phosphate buffer (pH 7.0; 1:1, v/v). Dimethylarginines were derived from o‐phthalaldehyde for the fluorescence detector and from 6‐ferrocenyl‐1‐hexanethiol for the electrochemical detector. The detection limits of the dimethylarginines in spiked plasma were 0.3–0.5 pmol by electrochemical detection and 1–2 pmol by fluorescence detection. The detection limits were improved over 30 times by electrochemical detection and 10 times by fluorescence detection compared with previous reports. In previous derivatization liquid chromatography, the reaction solutions, o‐phthalaldehyde, 2‐mercaptethanol and dimethylarginines were unstable and required quick derivatization at 4°C. By our proposed pre‐column methods, the dimethylarginines were derivatized at room temperature and the fluorescent products were stable for 6 h. The manipulation performance was greatly advanced compared with previous LC reports. This is the first report on stable and sensitive dimethylarginines by dual detection. The selectivity was also improved by dual detection. The proposed method was applied to preliminary monitoring of dimethylargines in plasma and urine. Copyright © 2012 John Wiley & Sons, Ltd.     

Determination of sugars by liquid chromatography with post-column catalytic derivatization and fluorescence detection

Summary A method for the determination of reducing sugars such as fructose and glucose and nonreducing sugar such as sucrose by high performance liquid chromatography followed by an acidic hydrolysis and a derivatization with benzamidine has been developed. After separation of sugars on a gel column packed with a polymer-based cation exchange material (Sugar-Pak I, Waters-Millipore), the sucrose is first hydrolysed in a solid phase reactor to convert it into reducing subunits. A post-column fluorigenic reaction with benzamidine under alkaline condition allows the selective determination of both natural and converted reducing carbohydrates.This procedure has proven to be selective (fluorigenic detection) and highly sensitive (allowing detection as little as picomoles amounts), reproducible and linear over a broad range of concentrations: 5×10^–4 to 1.0×10^–2 M.The applicability of this method to natural matrices such as plant extracts and beverages is also described. The sugar content of a barley extract has been determined and compared with a specific enzymatic test. The determined sugar content of natural and commercial lemon juices as well as of Cola beverages has been compared with those found by the conventional LC refractive index analytical procedure. In all cases, the results were comparable and were within the experimental errors of the methods.     

高效液相色谱-柱后在线光化学衍生荧光检测法测定辣椒油中4种苏丹红染料

建立了在线光化学衍生、荧光检测、高效液相色谱(HPLC)测定辣椒油中苏丹红I、II、III和B的方法。以乙腈-水为流动相,采用梯度洗脱方式在SB-C18色谱柱上分离。用实验室自制的程序控制时间/光强光化学反应器作为在线衍生装置,优化了光衍生反应的条件和荧光检测条件。3种不同加标浓度下,辣椒油样品中4种苏丹红染料的加标回收率为81.3%～100.4%。加标水平为0.8 mg/kg下荧光信号强度的相对标准偏差(RSD,n=6)为2.6%～3.8%。苏丹红I、II、III和B的检出限(LOD)和定量限(LOQ)范围分别为0.009～0.054 mg/kg和0.030～0.181 mg/kg,优于传统的HPLC分离、二极管阵列检测器检测方法。该方法具有简单、灵敏、选择性好的特点,适用于食品样品中苏丹红的常规分析。     

Rapid determination of nitrite in foods in acidic conditions by high‐performance liquid chromatography with fluorescence detection

In this study, a simple, rapid, and sensitive method for the determination of nitrite (NO₂^?) in food samples by high‐performance liquid chromatography with fluorescence detection in acidic conditions had been developed. The derivatization of the nitrite with 2,3‐diaminonaphthalene was performed in acidic conditions to yield the highly fluorescent 2,3‐naphthotriazole, which was directly analyzed by high‐performance liquid chromatography with fluorescence detection without adjusting the solution to alkaline. The analysis column was reversed‐phase C₈ column. A constant flow rate of 1.0 mL/min was employed using water/acetonitrile as the mobile phase in isocratic mode (70:30, v/v). Fluorescence was monitored with excitation at 375 nm and emission at 415 nm. The standard calibration curves were linear for nitrite in different matrixes in the concentration range of 0–100 μg/L, and the correlation coefficients ranged from 0.9978 to 0.9998. The limits of detection and quantification were in the ranges of 0.012–0.060 and 0.040–0.20 mg/kg, respectively. The recoveries of nitrite from samples spiked at three different concentrations were 74.0–113.2%, and the relative standard deviations of the recovery results (n = 6) were 1.67–10.8%. The proposed method has good repeatability and is very sensitive and simple. It has been successfully used to determine nitrite in foods.     

高效液相色谱荧光检测法测定药物中的氯乙酰氯

建立测定药物中氯乙酰氯含量的高效液相色谱–荧光检测方法。以吖啶酮乙酰肼为荧光标记试剂,对氯乙酰氯进行柱前衍生。在室温下反应15 min,衍生产率达到最大。衍生溶液在XDB–C18柱上,以水和乙腈为流动相进行分析,激发波长和发射波长分别为255 nm和429 nm。氯乙酰氯浓度在1~1 000 nmol/L范围内与色谱峰面积具有良好的线性关系,线性相关系数r=0.999 9。方法的检出限为0.35 nmol/L,仪器精密度和方法精密度分别为0.52%和0.67%(n=6)。样品加标回收率为92.5%~95.6%。该方法简单、准确,精密度良好,可用于测定药物中氯乙酰氯的残留量。     

Analysis of sialic acid levels in Chinese intravenous immunoglobulins by high‐performance liquid chromatography with fluorescence detection

Intravenous immunoglobulin (IVIg) is increasingly used for the treatment of autoimmune and systemic inflammatory diseases with both licensed and off‐label indications. Recent studies indicated that IVIg‐mediated immunomodulation and anti‐inflammation are closely associated with the IgG sialylation, especially with IgG crystallizable fragment (Fc) sialylation. The sialic acid levels of the IgG molecules and Fc fragments in 12 IVIg preparations from six Chinese manufacturers were evaluated. The Fc fragments were derived from the papain digestion of IVIg, followed by affinity and size exclusion chromatography. The sialic acid levels in Fc fragments and IVIg preparations were determined by high‐performance liquid chromatography with fluorescence detection, after the sialic acid residues were released from the proteins. The results showed that the sialic acid levels in Chinese IVIg preparations ranged from 0.875 (mol/mol IgG) to 1.085 (mol/mol IgG), and the sialic acid levels in Fc fragments were from 0.321 (mol/mol Fc) to 0.361 (mol/mol Fc). Furthermore, the sialic acid levels of IVIg preparations and Fc fragments from different Chinese manufactures were significantly different. These findings will contribute to an increased understanding of Chinese IVIg preparations and the relationship between the sialic acid levels in IVIg preparations and their clinical efficacy in future clinical studies.     

Analysis of free amino acids in Amur sturgeon by ultra‐performance liquid chromatography using pre‐column derivatization with 6‐aminoquinolyl‐carbamyl

A rapid, sensitive, and reliable ultra‐performance liquid chromatography (UPLC) coupled with photodiode array detection method was developed for the amino acid analysis of Amur sturgeon (Acipenser schrenckii Brandt). The method uses minimal sample volume and automated online precolumn derivitization of amino acids with fluorescent 6‐aminoquinolyl‐carbamyl reagent. The chromatographic separation was achieved by UPLC, which used a column with 1.7 μm particle packing that enabled higher speed of analysis, peak capacity, greater resolution, and increased sensitivity. Amino acid derivatives obtained under optimal conditions were separated on a Waters UPLC BEH C₁₈ column with Acetonitrile–acetate buffer as mobile phase. Matrix effects were investigated and good linearities with correlation coefficients better than 0.9949 were obtained over a wide range of 5–1000 μmol/L for all amino acids. The simple sample preparation and minimal sample volume make the method useful for the quantitation of 17 amino acids in Amur sturgeon samples. It is concluded that a rapid and robust platform based on UPLC was established, and a total of 17 amino acids of Amur sturgeon were tentatively detected. This method showed good accuracy and repeatability that can be used for the quantification of amino acids in real samples.     

Determination of estrone and 17α‐ethinylestradiol in digested sludge by ultrasonic liquid extraction and high‐performance liquid chromatography with fluorescence detection

Estrone, 17β‐estradiol and 17α‐ethinylestradiol are increasingly recognised as important micropollutants to be monitored in wastewater treatment plants. These estrogens are retained onto sludge due to their high adsorption and since they are largely used in land applications, the monitoring of these chemicals in sludge samples is of great importance. This study describes a method for the determination of estrone and 17α‐ethinylestradiol in fresh sludge samples. After spiking fresh digested sludge with estrone and 17α‐ethinylestradiol and maintaining in contact during 5, 30 and 60 min, the freeze‐dried samples were subjected to ultrasonic liquid extraction, with methanol and acetone, and analysed by high‐performance liquid chromatography with fluorescence detection. The average recoveries obtained for estrone and 17α‐ethinylestradiol using the different contact times were 103 ± 3 and 97 ± 4%, respectively. Fresh sludge samples from one waste water treatment plant located in Portugal were analysed and estrone was detected in primary fresh sludge, anaerobic digested sludge and dehydrated sludge at a concentration in the range of 1–4.8 μg/g. The method here developed does not require any sample clean‐up, being fast and simple, reliable and inexpensive, making possible its application for monitoring the contamination of sludge with these estrogens.     

柱前衍生高效液相色谱-荧光检测法测定血浆中同型半胱氨酸

建立了一种柱前衍生高效液相色谱-荧光检测法用于测定血浆中同型半胱氨酸(Hcy)。使用三(2-羧乙基)膦盐酸盐(TCEP)为还原剂,N-(1-芘)马来酰亚胺(NPM)为衍生剂进行样品预处理,Agilent Hypersil C-18柱(250 mm×4.0 mm, 5 μm)进行分离,流动相为15 mmol/L醋酸钠-乙腈-混合酸(300 mL水中含1 mL醋酸和1 mL磷酸)混合溶液,采用梯度洗脱,荧光检测激发波长为330 nm,发射波长为380 nm。Hcy的回收率为(102.08±4.94)%。线性范围为0.500～100 μmol/L,检出限（以信噪比为3计）为0.016 μmol/L。日内与日间相对标准偏差均小于5%。利用该方法对7例高血压患者和7例健康志愿者的血浆进行了测定,结果表明两组间的Hcy含量存在显著的差异(p＜0.05)。本方法简单、快速、灵敏、特异,适用于血浆Hcy的临床定量测定。     

Determination of glutathione content in grape juice and wine by high-performance liquid chromatography with fluorescence detection

A modified preparation of sample was developed for the determination of glutathione content in grape juice and wine by high-performance liquid chromatography with fluorescence detection, using on-line pre-column derivatization. Ice-cold deoxygenated methanol was used to deactivate the oxidation enzymes in juices or wines and keep the glutathione stable. The optimum recovery of glutathione content in grape juice and wine was obtained when either the sample of grape juice or wine was mixed in ice-cold deoxygenated methanol in the ratio 10:90 (v:v) and further diluted in sodium acetate buffer in the ratio 1:1 (v:v). The optimized method was validated for linearity, limit of detection, limit of quantification, precision and uncertainty. According to the validation data the method is appropriate for the determination of glutathione content in grape juice and wine. Glutathione contents in grape juices made from White Muscat grapes and Sauvignon Blanc wines were analysed. The average glutathione content in 28 young Sauvignon Blanc wines was 12.5 mg L⁻¹.     

Solid‐phase extraction and residue determination of glyphosate in apple by ion‐pairing reverse‐phase liquid chromatography with pre‐column derivatization

A new method for glyphosate residue determination in apple has been developed. A SPE cartridge was used to clean up the samples before derivatization. Glyphosate was derivatized with 4‐chloro‐3,5‐dinitrobenzotrifluoride (CNBF) and quantified by reverse ion‐pair liquid chromatography using cetyltrimethylammonium bromide (CTAB) as ion‐pair reagent. In pH 9.5 H₃BO₃–Na₂B₄O₇ medium, the reaction of glyphosate with CNBF was complete after 30 min at 60°C. The stability of the derivative on exposure to light at room temperature in methanol–water was demonstrated. The labeled glyphosate was separated on a Kromasil C₁₈ column (250×4.6 mm, 5 μm) at room temperature and UV detection was applied at 360 nm. Separation was achieved within 15 min in gradient elution mode. The correlation coefficient for the method was 0.9998 at concentrations ranging from 0.1 to 50 μg/g. The calculated recoveries for glyphosate in apple were from 86.00 to 99.55%, and the relative standard deviations (n = 6) were from 1.43 to 6.32. The limit of detection was 0.01 μg/g for glyphosate in apple.     

Reversed‐phase high‐performance liquid chromatography method with fluorescence detection to screen nitric oxide synthases inhibitors

Nitric oxide synthase (NOS) inhibitors are potential drug candidates due to the critical role of an excessive production of nitric oxide in a range of diseases. At present, the radiometric detection of l ‐[³H]‐citrulline produced from l ‐[³H]‐arginine during the enzymatic reaction is one of the most accepted methods to assess the in vitro activity of NOS inhibitors. Here we report a fast, easy, and cheap reversed‐phase high‐performance liquid chromatography method with fluorescence detection, based on the precolumn derivatization of l ‐citrulline with o‐phthaldialdehyde/N‐acetyl cysteine, for the in vitro screening of NOS inhibitors. To evaluate enzyme inhibition by the developed method, N‐[3‐(aminomethyl)benzyl]acetamidine, a potent and selective inhibitor of inducible NOS, was used as a test compound. The half maximal inhibitory concentration obtained was comparable to that derived by the well‐established radiometric assay.     

Determination of multiple phytohormones in fruits by high‐performance liquid chromatography with fluorescence detection using dispersive liquid–liquid microextraction followed by precolumn fluorescent labeling

Plant hormone determination in food matrices has attracted more and more attention because of their potential risks to human health. However, analytical methods for the analysis of multiple plant hormones remain poorly investigated. In the present study, a convenient, selective, and ultrasensitive high‐performance liquid chromatography method for the simultaneous determination of multiple classes of plant hormones has been developed successfully using dispersive liquid–liquid microextraction followed by precolumn fluorescent labeling. Eight plant hormones in fruits including jasmonic acid, 12‐oxo‐phytodienoic acid, indole‐3‐acetic acid, 3‐indolybutyric acid, 3‐indolepropionic acid, gibberellin A₃, 1‐naphthylacetic acid, and 2‐naphthaleneacetic acid were analyzed by this method. The conditions employed for dispersive liquid–liquid microextraction were optimized systematically. The linearity for all plant hormones was found to be >0.9993 (R² values). This method offered low detection limits of 0.19–0.44 ng/mL (at a signal‐to‐noise ratio of 3), and method accuracies were in the range of 92.32–103.10%. The proposed method was applied to determine plant hormones in five kinds of food samples, and this method can achieve a short analysis time, low threshold levels of detection, and a high specificity for the analysis of targeted plant hormones present at trace level concentrations in complex matrices.     

Enantioselective micellar electrokinetic chromatography of dl‐amino acids using (+)‐1‐(9‐fluorenyl)‐ethyl chloroformate derivatization and UV‐induced fluorescence detection

Chiral analysis of dl ‐amino acids was achieved by micellar electrokinetic chromatography coupled with UV‐excited fluorescence detection. The fluorescent reagent (+)‐1‐(9‐fluorenyl)ethyl chloroformate was employed as chiral amino acid derivatizing agent and sodium dodecyl sulfate served as pseudo‐stationary phase for separating the formed amino acid diastereomers. Sensitive analysis of (+)‐1‐(9‐fluorenyl)ethyl chloroformate‐amino acids was achieved applying a xenon‐mercury lamp for ultraviolet excitation, and a spectrograph and charge‐coupled device for wavelength‐resolved emission detection. Applying signal integration over a 30 nm emission wavelength interval, signal‐to‐noise ratios for derivatized amino acids were up to 23 times higher as obtained using a standard photomultiplier for detection. The background electrolyte composition (electrolyte, pH, sodium dodecyl sulfate concentration, and organic solvent) was studied in order to attain optimal chemo‐ and enantioseparation. Enantioseparation of 12 proteinogenic dl ‐amino acids was achieved with chiral resolutions between 1.2 and 7.9, and detection limits for most derivatized amino acids in the 13–60 nM range (injected concentration). Linearity (coefficients of determination > 0.985) and peak‐area and migration‐time repeatabilities (relative standard deviations lower than 2.6 and 1.9%, respectively) were satisfactory. The employed fluorescence detection system provided up to 100‐times better signal‐to‐noise ratios for (+)‐1‐(9‐fluorenyl)ethyl chloroformate‐amino acids than ultraviolet absorbance detection, showing good potential for d ‐amino acid analysis.     

Determination of tryptophan in bee pollen and royal jelly by high‐performance liquid chromatography with fluorescence detection

A method for tryptophan analysis in bee pollen and royal jelly was developed using HPLC with fluorescence detection. To determine the free tryptophan in bee pollen and royal jelly, ultrasonic extraction was performed using water (pH 6.3)–acetonitrile (10:1, v/v) as extraction solvent. While determining the total tryptophan in these bee products, the method involves alkaline hydrolysis of the proteins with 4 mol/L sodium hydroxide at 110°C for 20 h under anaerobic conditions. The operating conditions for the HPLC analysis were: Symmetry C₁₈ column (4.6 × 250 mm, 5 µm), 0.1% trifluoroacetic acid–methanol (75:25, v/v) as the mobile phase at a flow rate of 1.0 mL/min at 30°C. The fluorescence detector was operated at an excitation wavelength of 280 nm and an emission wavelength of 340 nm. A linear response (r² > 0.9998) was obtained in the range 0.0625–5.0 µg/mL. The method was successfully applied to the determination of the free and total tryptophan contents in bee pollens, which were 0.069 ± 0.003 and 2.693 ± 0.476 mg/g, respectively, while only the total tryptophan was detected in royal jelly, with a content of 1.743 ± 0.066 mg/g. Copyright © 2009 John Wiley & Sons, Ltd.     

柱前衍生反相高效液相色谱-荧光检测法测定大鼠血浆中的奈替米星

建立了一种简便、灵敏的氯甲酸芴甲酯(FMOC-Cl)柱前衍生反相高效液相色谱-荧光检测血浆中奈替米星的新方法,同时研究了其药代动力学。对色谱条件进行了优化,采用ZORBAX Eclipse XDB-C8柱(150 mm×4.6 mm,5 μm),流动相为乙腈-水(体积比为85:15),流速为1.0 mL/min,荧光检测激发波长为265 nm,发射波长为315 nm,得到奈替米星的平均加标回收率为96.62%～100.84%(n=3),对奈替米星检测的线性范围为0.045～8.88 mg/L,相关系数为0.9993,方法的日内与日间精密度分别低于3%与3.5%,最低检出限(S/N=3)与定量限(以3倍检出限计)分别为0.01和0.03 mg/L。方法简便、快速、灵敏,样品用量少(30 μL奈替米星血浆溶液已能满足该药含量的测定以及药物代谢的研究),为大鼠体内奈替米星的药代动力学研究提供了可靠的分析手段。     

Ionic liquid foam floatation coupled with ionic liquid dispersive liquid–liquid microextraction for the separation and determination of estrogens in water samples by high‐performance liquid chromatography with fluorescence detection

An ionic liquid foam floatation coupled with ionic liquid dispersive liquid–liquid microextraction method was proposed for the extraction and concentration of 17‐α‐estradiol, 17‐β‐estradiol‐benzoate, and quinestrol in environmental water samples by high‐performance liquid chromatography with fluorescence detection. 1‐Hexyl‐3‐methylimidazolium tetrafluoroborate was applied as foaming agent in the foam flotation process and dispersive solvent in microextraction. The introduction of the ion‐pairing and salting‐out agent NH₄PF₆ was beneficial to the improvement of recoveries for the hydrophobic ionic liquid phase and analytes. Parameters of the proposed method including concentration of 1‐hexyl‐3‐methylimidazolium tetrafluoroborate, flow rate of carrier gas, floatation time, types and concentration of ionic liquids, salt concentration in samples, extraction time, and centrifugation time were evaluated. The recoveries were between 98 and 105% with relative standard deviations lower than 7% for lake water and well water samples. The isolation of the target compounds from the water was found to be efficient, and the enrichment factors ranged from 4445 to 4632. This developing method is free of volatile organic solvents compared with regular extraction. Based on the unique properties of ionic liquids, the application of foam floatation, and dispersive liquid–liquid microextraction was widened.