Hollow fiber-based liquid phase microextraction followed by analytical instrumental techniques for quantitative analysis of heavy metal ions and pharmaceuticals

Hollow-fiber liquid-phase microextraction(HF-LPME)and electromembrane extraction(EME)are miniaturized extraction techniques,and have been coupled with various analytical instruments for trace analysis of heavy metals,drugs and other organic compounds,in recent years.HF-LPME and EME provide high selectivity,efficient sample cleanup and enrichment,and reduce the consumption of organic sol-vents to a few micro-liters per sample.HF-LPME and EME are compatible with different analytical in-struments for chromatography,electrophoresis,atomic spectroscopy,mass spectrometry,and electrochemical detection.HF-LPME and EME have gained significant popularity during the recent years.This review focuses on hollow fiber based techniques(especially HF-LPME and EME)of heavy metals and pharmaceuticals(published 2017 to May 2019),and their combinations with atomic spectroscopy,UV-VIS spectrophotometry,high performance liquid chromatography,gas chromatography,capillary elec-trophoresis,and voltammetry.

Rapid analysis of fifteen sulfonamide residues in pork and fish samples by automated on-line solid phase extraction coupled to liquid chromatography–tandem mass spectrometry

The aim of this work was to develop an automated on-line solid phase extraction(SPE)with liquid chromatography-tandem mass spectrometry method for the detection of fifteen sulfonamides in pork and fish samples.Samples were extracted with 0.2%formic acid acetonitrile solution,purified by on-line SPE device with HLB column,then separated by XBridge C18 column,using 0.1%formic acid solution and acetonitrile as the mobile phase.Mass spectrometric data was acquired under multiple reaction monitoring(MRM)mode using positive ionization electrospray.Internal standard method was used in the quantification,good linear relationship was got in range of 0.1–100 ng/mL and correlation coefficient was higher than 0.9990.The limits of detection were in the range of 0.125–2.00g/kg and the limits of quantitation were in the range of 0.250–5.00g/kg.Recoveries of the method were in range of 78.3%–99.3%,relative standard deviation were lower than 10%.The method was simple,sensitivity,and could be used for routine supervision and analysis of fifteen sulfonamides in pork and fish.

Dynamic microwave-assisted extraction combined with liquid phase microextraction based on the solidification of a floating drop for the analysis of organochlorine pesticides in grains followed by GC

A convenient,cost-effective and fast method using dynamic microwave-assisted extraction and liquid phase microextraction based on the solidification of a floating drop was proposed to analyze organochlorine pesticides in grains including rice,maize and millet.Twelve samples can be processed simultaneously in the method.During the extraction process,10%acetonitrile-water solutions containing 110μL of n-hexadecane were used to extract organochlorine pesticides.Subsequently,1.0 g sodium chloride was placed in the extract,and then centrifuged and cooled.The n-hexadecane drops containing the analytes were solidifi ed and transferred for determination by gas chromatography-electron capture detector without any further filtration or cleaning process.Limits of detection for organochlorine pesticides were 0.97–1.01μg/kg and the RSDs were in the range of 2.6%–8.5%.The developed technology has succeeded in analyzing six real grains samples and the recoveries of the organochlorine pesticides were 72.2%–94.3%.Compared with the published extraction methods,the developed method was used to analyze organochlorine pesticides in grains,being more environmentally friendly,which is suitable for the daily determination of organochlorine pesticides.

Determination of Sulfadimidine in Royal Jelly by C_(18)-functionalized Magnetic Silica Nanoparticles Solid Phase Extraction-High Performance Liquid Chromatography-Tandem Mass Spectrometry

[Objective] This study aimed to develop a method of C_18-functionalized magnetic silica nanoparticles solid phase extraction-high performance liquid chro- matography-tandem mass spectrometry for the determination of sulfadimidine in royal jelly. [Method] The royal jelly samples were pretreated by MCX SPE column and C_18-functionalized magnetic silica nanoparticles, and the purified samples were de- tected by HPLC-MS/MS. [Result] The detection method showed a good linear rela- tionship in the range of 5-80 ugkg （r=0.993 1）. The recovery ranges were between 93%- 104% with the relative standard deviations （RSD） below 11.3%. [Conclusion] Combined with automation equipment, the method is simple, fast, time-saving, and easy to real- ize the automation of sulfadimidine in the royal jelly samples before determination.

Simultaneous Determination of Bisphenols and Alkylphenols in Water by Solid Phase Extraction and Ultra Performance Liquid Chromatography-tandem Mass Spectrometry

To establish an analytical method for determination of four bisphenols （BPA, BPB, BPF, and BPS） and two alkylphenols （4-n-OP, 4-n-NP） in water by ultra performance liquid chromatography- tandem mass spectrometry （UPLC/MS/MS）. The water samples were extracted and condensed with solid-phase extraction （SPE） using C18 cartridges and eluted by acetonitrile. Separation was carried out with Acquity BEH C8 column and detection were performed by UPLC/MS/MS. Quantification was calculated by using the internal standard BPA-d16 and 4-n-NP-d8. The linear correlation coefficients of these compounds in the range of 1.0-100.0μg/L were all over 0.999. The minimum detectable concentrations were 0.75-1.0 ng/L, and the recoveries ranged from 87.0% to 106.9%.

Uncertainty Evaluation of Determination of Microcystin MC-LR in Environmental Samples by Solid Phase Extraction-Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

To assess uncertainty of determination of MC-LR in environmental samples by solid phase extraction- ultra performance liquid chromatography- tandem mass spectrometry,the sources of the uncertainty were evaluated firstly,and the expanded uncertainty was calculated finally.The results show that when MC-LR concentration in the water samples was 0.50 μg/L,the expanded uncertainty was 0.00628 μg/L(k=2).

Kinetic Mass Transfer Between Non-aqueous Phase Liquid and Gas During Soil Vapor Extraction

The mass transfer between non-aqueous phase liquid(NAPL) phase and soil gas phase in soil vapor extraction(SVE) process has been investigated by one-dimensional venting experiments. During quasi-steady volatilization of three single-component NAPLs in a sandy soil, constant initial lumped mass transfer coefficient (λgN,0) canbe obtained if the relative saturation (ξ) between NAPL phase and gas phase is higher than a critical value (ξc), andthe lumped mass transfer coefficient decreases with ξ when ξ＜ξc. It is also shown that the lumped mass transfercoefficient can be increased by blending porous micro-particles into the sandy soil because of the increasing of theinterfacial area.

Ionic Liquid-salt Aqueous Two-phase System, a Novel System for theExtraction of Abused Drugs

A 1-butyl-3-methylimidazolium chloride-salt aqueous two-phase system was studied on extraction of abused drugs. The effects of sorts of salts, temperature, concentration of salt and drugs on system were investigated systematically. A satisfactory extraction efficiency of 93% was obtained for papaverine while that of morphine was 65%. The extraction mechanism was primarily discussed.

Comparison of liquid-liquid extraction-thin layer chromatography with solid-phase extraction-high-performance thin layer chromatography in detection of urinary morphine

Liquid-liquid extraction-thin layer chromatography （LLE-TLC） has been a common and routine combined method for detection of drugs in biological materials. Solid-phase extraction （SPE） is gradually replacing the tra- ditional LLE method. High performance thin layer chromatography （HPTLC） has several advantages over TLC. The present work studied the higher efficiency of a new SPE-HPTLC method over that of a routine LLE-TLC method, in extraction and detection of urinary morphine. Fifty-eight urine samples, primarily identified as mor- phine-positive samples by a strip test, ＇were re-screened by LLE-TLC and SPE-HPTLC. The results of LLE-TLC and SPE-HPTLC were then compared with each other. The results showed that the SPE-HPTLC detected 74% of total samples as morphine-positive samples whereas the LLE-TLC detected 48% of the same samples. We further discussed the effect of codeine abuse on TLC analysis of urinary morphine. Regarding the importance of morphine detection in urine, the present combined SPE-HPTLC method is suggested as a replacement method for detection of urinary morphine by many reference laboratories.

Isolation and Purification of Unstable Iridoid Glucosides from Traditional Chinese Medicine by Preparative High Performance Liquid Chromatography Coupled with Solid-phase Extraction

An efficient preparative method was successfully developed for isolation and purification of unstable components from medicinal plant extracts, using a combined method of preparative high performance liquid chro-matography(HPLC) and solid-phase extraction(SPE). The aim of this study was to obtain an effective method with high preparative efficiency and importantly to avoid the transformation of unstable compounds. The preparative HPLC system was based on an LC/MS controlled four-channel autopurification system. The SPE method was performed with a C18 packing material to trap the target compounds and to remove the acidic additive derived from the mobile phase. Using this method, the unstable iridoid glucosides(IGs) as model compounds were successfully isolated and purified from the extract of Hedyotis diffusa Willd. Six IGs(including one new minor IG) and one nucleotide compound were simultaneously obtained, each with a purity of 91% as determined by HPLC. The structures of the isolated compounds were identified by UPLC/Q-TOF MS, UV, 1D and/or 2D NMR. It was demonstrated that the combination of preparative HPLC with SPE is a versatile tool for preparative purification of unstable compounds from complex natural products.

Determination of Trace Amount of Polycyclic Aromatic Hydrocarbons in Urban Sewage by Solid-phase Extraction Coupled with High Performance Liquid Chromatograph

[Method] This study aimed to determine trace amount of polycyclic aromatic hydrocarbons(PAHs) in urban sewage by using solid-phase extraction(SPE) coupled with high performance liquid chromatograph(HPLC).[Method] From the aspects of solid-phase extraction column,elution solvent,elution volume,elution speed and so forth,the test conditions of SPE-HPLC method were optimized,and trace amount of PAHs in urban sewage was determined.[Result] The optimized solid-phase extraction conditions were SUPELCLEAN LC-18 solid-phase extraction column,methylene dichloride as elution solvent,15 ml elution volume,2 ml/min elution speed,5 ml/min loading speed,1 000 ml water with 200 ml methanol loading volume.Under the optimized extraction conditions,the recovery was high,namely 76.3%-105.2%;relative standard deviation was 3.8%-6.0%,showing good precision;detection limit was low,only 0.000 8-0.048 0 μg/L.[Conclusion] This method is user-friendly,with high sensitivity and good precision,and suitable for continuous determination of a large volume of water samples.

Extraction of Tetracycline via Ionic Liquid Two-phase System

A new method to extract and separate tetracycline（TC） in a new aqueous tyro-phase system（ATPS） consisting of hydrophilic [Bmim]BF4 and NaH2PO4 was investigated. The effects of the amount of salt, ionic liquid as well as tetracycline on extraction efficiency were studied systematically. The results show that ionic liquid-ATPS exhibited the highest extraction efficiency higher than 90%. When the concentration of NaH2PO4 was 33.3%--38.5% （mass fraction）, the amounts of ionic liquid and TC were 1.0--2.0 mL and 1.8 mL, respectively, and ionic liquid could be re-used.

Determination of Quinolone Antibiotics in Water Using Solid Phase Extraction-High Performance Liquid Chromatography-Fluorescence Method

[Objective] To develop a solid phase extraction-high performance liquid chromatography-fluorescence method for determination of quin- olone antibiotics in water. [ Metbod] The standard curves of four quinolones （norfloxacin, ciprofloxacin, Iomefloxacin and enrofloxacin） were pre- pared. The detection limit in water and recovery were determined. The water samples collected from different areas, river and tap water were trea- ted using solid-phese extraction method and analyzed by high performance liquid chromatography. Then the concentration of quinolones antibiotics was determined by fluorescence method. [ Result] The detection limit of quinolone antibiotics in water was 0.083 -0.248 μg/L, and their recovery was 63.7% -134.1%. The four quinolone antibiotics at different levels were detected in various water samples, and the total concentration of quin- olone antibiotics was 0.045 -3.969 μg/L. The total concentration of quinolone antibiotics was higher in the water samples collected from rivers in Shenzhen area than in the sewage samples. The four quinolone antibiotics could be detected in all tap water samples. [ CoaduLsion ] The solid phase extraction-high performance liquid chromatography-fluorescence method is feasible and effective to detect quinolones in water. In addition, this method needs low cost and can meet requirements of daily monitorina and analysis.

Molecularly Imprinted Micro-Solid-Phase Extraction for the Selective Determination of Phenolic Compounds in Environmental Water Samples with High Performance Liquid Chromatraphy

2,4,6-trichlorophenol molecularly imprinted suspension polymer has been prepared and applied to the molecularly imprinted micro-solid-phase extraction procedure for selective preconcentration of phenolic compounds from environmental water samples. The influence of functional monomer, cross-linker, polymerization condition, porogen, and the ratio of template molecule and functional monomer to cross-linker on the size of the obtained particles were investigated. It was found that methyacrylic acid as functional monomer, divinylbenzene as cross-linker, the molar ratio of template molecule and functional monomer to cross-linker was 1:4:20, the amount of AIBN was 100 mg, ultraviolet radiation at 365 nm were the optimal conditions, and at these conditions, the polymers had the best adsorption efficiency and had the monodispersity of 2 - 3 μm microsphere particles. The characteristics of the MIMSPE method were valid by high performance liquid chromatography. This MIMSPE-HPLC method has been successfully applied to the direct preconcentration and determination of phenolic compounds (phenol, 4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, pentachlorophenol) in environmental water samples.

Synthesis and Solid Phase Extraction Performance Study of NNAL-specific Molecularly Imprinted Polymers Using Dummy Templates

Dummy molecularly imprinted polymers （DMIPs） for 4-（methylnitrosamino）-1-（3-pyridyl）-1-butanol （NNAL） were produced using three structural analogues as dummy template molecules. The chosen analogues were 4-（acetymethylamino）-1-（3-pyridyl）-butanol, 4- （methylamino）-1-（3-pyridyl）-1-butanol, and 1-（3-pyridyl）-1,4,-butanediol. The molecular recognition characteristics of the produced polymers were evaluated by X-ray photoelec- tron spectroscopy （XPS） and Fourier transform infrared spectroscopy （FT-IR）. Interactions between NNAL and methacrylic acid should be cooperative hydrogen bonds while the ni- trogen atom of the pyridine ring and the oxygen atom of the nitroso group in NNAL are two of the hydrogen-bond acceptors. It was further demonstrated that DMIP synthesized by 4-（acetymethylamino）-1-（3-pyridyl）-butanol had the best binding performance by XPS and FT-IR. Then dummy molecularly imprinted solid phase extraction （DMISPE） was developed for the determination of the analyte using the hit polymer as the sorbing material. Under optimal conditions, the recovery of NNAL dissolved in standard solution reached 93%. And the investigated polymer exhibited much higher binding of NNAL when nicotine was acted as the competitive molecule. Also the proposed method was applied to the measurement of NNAL spiked in blank urine samples with recoveries ranging from 87.2% to 101.2%.

A novel surface molecularly imprinted polymer as the solid-phase extraction adsorbent for the selective determination of ampicillin sodium in milk and blood samples

Surface molecularly imprinted polymers （SMIPs） for selective adsorption of ampicillin sodium were synthesized using surface molecular imprinting technique with silica gel as a support. The physical and morphological characteristics of the polymers were investigated by scanning electron microscope （SEM）, Fourier transform infrared spectroscopy （FT-IR）, thermogravimetric analysis （TGA）, elemental analysis and nitrogen adsorption-desorption test. The obtained results showed that the SMIPs displayed great adsorption capacity （13.5 lag/mg）, high recognition ability （the imprinted factor is 3.2） and good binding kinetics for ampicillin sodium. Finally, as solid phase extraction adsorbents, the SMIPs coupled with HPLC method were validated and applied for the enrichment, purification and determination of anapicillin sodium in real milk and blood samples. The averages of spiked accuracy ranged from 92.1% to 107.6%. The relative standard deviations of intra- and inter-day precisions were less than 4.6%. This study provides a new and promising method for enriching, extracting and determining ampicillin sodium in complex biological samples.

A highly sensitive SPE-liquid/liquid extraction-RPLC analytical method for the determination of 6β-hydroxycortisol and cortisol in cancer patients' urine

A highly sensitive SPE-liquid/liquid extraction RPLC method has been developed for the analysis of 6β-hydroxycortisol and cortisol in the urine of cancer patients. Methods： After SPE column purification and liquid-liquid extraction, the sample test solutions were analyzed with RPLC using a C18 analytical column. This improved analytical method has been validated for linearity, accuracy （recovery from urine）, repeatability （within-day and between-day precision）, specificity, sensitivity, and stability. This SPE-liquid/liquid extraction-RPLC is rapid, simple, accurate and reproducible. The technique is particularly useful for monitoring the CYP3A activity of cancer patients in clinical settings. The results are expressed as the ratio of 6β-hydroxycortisol to cortisol. Results： The CYP3A activity from a total of 153 samples was measured using this improved method. Considerable variation in the CYP3A activity of different cancer patients has been documented. Thus, personalized medical treatment based on the individual metabolic enzyme activity level is necessary. Conclusion： This new analytical method facilitates such individualized medical treatments.

Matrix Solid-phase Dispersion Extraction of Alkaloids from the Roots of Aconitum kusnezoffii Reichb

Matrix solid-phase dispersion（MSPD） was developed for the extraction of four alkaloids, including aconitine, mesaconitine, hypaconitine and deoxyaconitine, from the roots ofAconitum kusnezoffii Reichb. The determination of the analyte was carried out by high performance liquid chromatography with UV detection. The alkaline alumina was used as sorbent. The mixture of acetonitrile and water was used as elution solvent. Several extraction parameters, such as type of sorbent, the ratio of sample to solid support material, type of the elution solvent and the volume of the elution solvent were tested. Mean recoveries ranged from 93.16% to 102.73%, with relative standard deviations from 0.27% to 4.17%. With the extraction efficiency and time expenditure taken into account, MSPD extraction should be a comparatively good method.

Development of a Rapid and Efficient Liquid Chromatography Method for Determination of Gibberellin A4 in Plant Tissue, with Solid Phase Extraction for Purification and Quantification

A new, rapid and efficient reverse phase Liquid Chromatography (RP-LC) method was developed for determination of Gibberellin A4 (GA4) in samples of flower stalk of Dasylirion cedrosanum and vegetative tissue of Epithelantha micromeris. Purification of GA4 was carried out by solid phase extraction (SPE), in Epithelantha micromeris. In the chromatography method was obtaining a retention time of 2.1 min, using Hypersil GOLD C-18 column (100 × 4.6 mm dim and size particle 5 μ), mobile phase 50/50 acetonitrile/water and a flow 1.0 ml/min. Detection was carried out by a UV detector set at 205 nm, and a quantization limit of 0.4 mg/L. The obtained correlation coefficient was 0.995.

固相萃取结合高效液相色谱-串联质谱测定胎便中14种全氟和多氟烷基化合物

全氟和多氟烷基化合物(PFASs)是一类人工合成的物质,由于其热稳定、疏水、疏油等优良性质而被广泛使用于生活和生产中.PFASs具有环境持久性、生物累积性、多种毒性等特性,且可以通过胎盘屏障进入到胎儿体内,进而对胎儿健康产生潜在危害.胎便中积累了妊娠期间暴露于胎儿的外源性化合物,可用于监测PFASs对胎儿的宫内暴露特征.本研究基于固相萃取结合高效液相色谱-串联质谱技术,建立了胎便中14种PFASs的分析方法.采用乙腈/水(9∶1,V/V)对0.2 g冻干胎便样品进行超声提取,提取液经Envi-carb和Oasis WAX小柱固相萃取,0.1%氨甲醇洗脱.以10 mmol·L^(−1)乙酸铵水溶液和乙腈作为流动相对目标化合物进行梯度洗脱,采用Acquity UPLC BEH C18色谱柱进行分离,基于多反应监测负离子模式采集,内标法定量.结果表明,在2、5、20 ng·g^(−1)的加标浓度下,14种PFASs的回收率为65%—149%,相对标准偏差为3%—22%,方法检出限(MDLs)为0.001—0.149 ng·g^(−1),方法定量限(MQLs)为0.003—0.495 ng·g^(−1).使用该方法测定了10个胎便样品,ΣPFASs浓度范围为<MDLs—2.49 ng·g^(−1).该方法操作简单、便捷、灵敏度高且定量准确,为系统性研究胎便中PFASs的赋存特征及暴露风险提供了技术基础.