甲氧苄啶分子印迹涂层搅拌棒在复杂样品痕量甲氧苄啶和磺胺药物分析中的应用(英文)

研制了甲氧苄啶分子印迹吸附萃取搅拌棒涂层,并应用于复杂样品中痕量甲氧苄啶和磺胺药物的分析。分子印迹涂层的厚度约为21.5μm,相对标准偏差为5.9%(n=10),涂层均匀、致密,具有良好的热稳定性和化学稳定性。分子印迹涂层的萃取容量是非印迹涂层萃取容量的1.7倍,分子印迹涂层对抗菌增效剂、磺胺药物、三嗪化合物和甲氨蝶呤都表现出良好的选择性吸附萃取能力。建立了分子印迹吸附萃取搅拌棒联用高效液相色谱的分析方法,成功应用于加标尿样和血浆中痕量甲氧苄啶的分析,线性范围为5～200μg/L,检出限为1.6μg/L,在尿样和血浆中的回收率范围分别为84.5%～91.7%和71.9%～85.1%,标准偏差分别为2.9%～4.4%和3.0%～7.3%。该方法还应用于加标牛奶中痕量磺胺药物的分析,线性范围为10～200μg/L,检出限在4.5～6.1μg/L之间,回收率为83.2%～110.2%,标准偏差为4.1%～8.0%.     

Investigation of ractopamine molecularly imprinted stir bar sorptive extraction and its application for trace analysis of β2-agonists in complex samples

In this paper, a novel molecularly imprinted polymer (MIP) coated stir bar with ractopamine as template by glass capillary filling with magnetic core as substrate was prepared reproducibly. The ractopamine MIP coating was homogeneous and porous with the average thickness of 20.6 μm. The extraction apparatus for the stir bar was improved to avoid coating loss. The MIP-coated stir bar showed better extraction capacity and good selectivity than that of non-imprinted polymer (NIP) coated stir bar to ractopamine and its analogues. The extraction capacities of ractopamine, isoxsuprine, clenbuterol and fenoterol for MIP-coated stir bar were 3.3, 3.1, 2.8 and 2.4 times as much as that of the NIP coated stir bar, respectively. The MIP-coated stir bars could be used at least 40 times without apparent damage and kept in dried air for 8 months without reduce of extraction ability. A method for the determination of β₂-agonists in complex samples by MIP-coated stir bar sorptive extraction coupled with high-performance liquid chromatography (HPLC) was developed. The linear ranges were 0.5–40 μg/L for ractopamine and 1.0–40 μg/L for isoxsuprine and clenbuterol. The detection limits were within the range of 0.10–0.21 μg/L. The method was successfully applied to the analysis of β₂-agonists in spiked pork, liver and feed samples with the recoveries of 83.7–92.3%, 80.5–90.2% and 73.6–86.2%, respectively. The RSDs was within 2.9–8.1%. The method is very suitable for the determination of trace β₂-agonists in pork, liver and feed samples.     

Development of selective and chemically stable coating for stir bar sorptive extraction by molecularly imprinted technique

A novel stir bar coated with molecularly imprinted polymer (MIP) as selective extraction phase for sorptive extraction of triazine herbicides was developed. The stir bar was prepared by chemically bonding the MIP to the glass bar to improve its stability. A homogeneous and porous structure was observed on the stir bar surface. Extraction performance shows that the MIP-coated stir bar has stronger affinity to the template molecule terbuthylazine as compared with that of the reference stir bar without addition of template. Owning to the shape and structural compatibility, the obtained stir bar also demonstrated specific selectivity to the structural related-compounds of nine triazines, and thus can be applied to simultaneous determination of these compounds from complex samples coupled with high performance liquid chromatography. Four complex samples with different matrix, including rice, apple, lettuce and soil were used to evaluate this proposed method. The limits of detection obtained are in the range of 0.04-0.12 μg L⁻¹, and the recoveries for the spiked rice, apple, lettuce and soil samples were 80.8-107.7%, 80.6-107.8%, 72.0-109.8% and 89.0-114.8% with RSD from 1.2 to 7.9%, respectively. Moreover, this MIP-coated stir bar was firm, durable and can be prepared simply and reproducibly. The developed coating method would be useful to prepare a range of selective stir bars in order to extend the applicability of stir bar sorptive extraction (SBSE) in complex sample analysis.     

Novel molecularly imprinted stir bar sorptive extraction based on an 8-electrode array for preconcentration of trace exogenous estrogens in meat

A novel 8-electrode array as stir bar was designed for selective extraction of trace level exogenous estrogens from food samples, followed by liquid desorption and HPLC-photodiode array detection. The array consisted of 8 screen-printed electrodes and each electrode was modified with Fe₃O₄@meso-/macroporous TiO₂ microspheres and molecularly imprinted film (m-TiMIF). The fabrication of the imprinted film coating was very simple without organic solvents and chemical grafting. Both bisphenol A (BPA) and diethylstilbestrol (DES) were employed as templates in m-TiMIF fabrication in order to enrich both targets simultaneously. Interestingly, the imprinted stir bar array showed higher extraction capacity and selectivity for BPA and DES than the non-imprinted counterpart. Meanwhile, it exhibited fast adsorption and desorption kinetics due to increased mass transport in the ultra-thin film. Importantly, the m-TiMIF coating was robust enough for at least 20 uses without obvious alteration in extraction performance. The main parameters affecting the extraction efficiency, including stir speeding, sample pH, ionic strength, extraction time, desorption solvent and time, were optimized. Under optimal experimental conditions, the limits of detection (S/N = 3) of the developed method were 0.28 and 0.47 μg L⁻¹ for BPA and DES respectively, with enrichment factors of 32.6 and 52.8-fold. The linear ranges were 3.0–1500 μg L⁻¹ and 4.0–1500 μg L⁻¹ for BPA and DES, respectively. The m-TiMIF-coating conferred better recovery and selectivity, compared with the commercial stir bar coating. The new method was successfully applied to assess BPA and DES in pork and chicken samples with satisfactory recovery.     

Cadmium (II) imprinted 3-mercaptopropyltrimethoxysilane coated stir bar for selective extraction of trace cadmium from environmental water samples followed by inductively coupled plasma mass spectrometry detection

Cd(II) imprinted 3-mercaptopropyltrimethoxysilane (MPTS)-silica coated stir bar was prepared by sol–gel technique combining with a double-imprinting concept for the first time and was employed for stir bar sorptive extraction (SBSE) of trace Cd(II) from water samples followed by inductively coupled plasma mass spectrometry (ICP-MS) detection. A tetramethoxysilane (TMOS) coating was first in situ created on the glass bar surface. Afterward, a sol solution containing MPTS as the functional precursor, ethanol as the solvent and both Cd(II) and surfactant micelles (cetyltrimethylammonium bromide, CTAB) as the template was again coated on the TMOS bar. The structures of the stir bar coating were characterized by FT-IR spectroscopy. Round-bottom vial was used for the extraction of Cd(II) by SBSE to avoid abrasion of stir bar coatings. The factors affecting the extraction of Cd(II) by SBSE such as pH, stirring rate and time, sample/elution volume and interfering ions have been investigated in detail, and the optimized experimental parameters were obtained. Under the optimized conditions, the adsorption capacities of non-imprinted and imprinted coating stir bars were found to be 0.5 μg and 0.8 μg bar⁻¹. The detection limit (3σ) based on three times standard deviations of the method blanks by 7 replicates was 4.40 ng L⁻¹ and the relative standard deviation (RSD) was 3.38% (c = 1 μg L⁻¹, n = 7). The proposed method was successfully applied for the analysis of trace Cd(II) in rain water, East Lake and Yangtze River water. To validate the proposed method, certified reference material of GSBZ 50009-88 environmental water was analyzed and the determined value is in a good agreement with the certified value. The developed method is rapid, selective, sensitive and applicable for the analysis of trace Cd(II) in environmental water samples.     

Analysis of chlorophenols,bisphenol-A, 4-tert-octylphenol and 4-nonylphenols in soil by means of ultrasonic solvent extraction and stir bar sorptive extraction with in situ derivatisation

A novel method based on ultrasonic solvent extraction and stir bar sorptive extraction for the analysis of phenolic organic pollutants including chlorophenols, bisphenol-A, 4-tert-octylphenol and 4-nonylphenol in soil samples was developed. The different parameters that affect both the extraction of analytes from the soil samples, such as solvent selection, extraction time, and the partitioning from the solvent/water mix to poly(dimethylsiloxane) (PDMS) were studied. The final selected conditions consisted of the extraction of 1 g of soil with 15 mL methanol by sonication for 30 min. The methanol extract was mixed with 85 mL of Milli-Q water and extracted by means of stir bar sorptive extraction with in situ derivatisation. The stir bars were analyzed by thermal desorption–gas chromatography–mass spectrometry (TD–GC–MS). The effects of the matrix on the recovery of the various pollutants under the developed method were studied using two soils with very different physicochemical properties. Method sensitivity, linearity, repeatability, and reproducibility were also studied. Validation and accuracy of the method were conducted by analyzing two commercial certified reference materials and by comparing the analysis of real samples with the proposed method and a classical method using pressurized solvent extraction (PSE)–GC–MS. The main advantage of this method is a substantial solvent reduction. For the extraction of only 1 g of solid sample allowing limits of detection ranging from 0.2 to 1.7 μg kg⁻¹ dw. Repeatability and reproducibility variation were lower than 20% for all investigated compounds. Results of the certified reference materials and the real samples verify the high accuracy of this method.     

Optimization of Polyurethane Foams for Enhanced Stir Bar Sorptive Extraction of Triazinic Herbicides in Water Matrices

In this work, polyurethane foams (PU) were developed, characterized and applied as new generation polymeric phases for stir bar sorptive extraction (SBSE) using seven triazinic herbicides (simazine, atrazine, prometon, ametryn, propazine, prometryn and terbutryn) as model compounds in water matrices. Assays performed for PU synthesis and characterization demonstrated that seven formulations presented remarkable stability and excellent mechanical and chemical resistance, for which the P₆ formulation showed the best results. By performing systematic assays on 25 mL of water samples spiked at the 10 μg/L level, it was established that the best experimental conditions using stir bars coated with P₆ were an equilibrium time of 6 h (1250 rpm), 5% of methanol as organic modifier, followed by liquid desorption with methanol as back extraction solvent under ultrasonic treatment (20 min) and high performance liquid chromatography with diode array detection (SBSE(PU)-LD-HPLC-DAD). This methodology provided good recoveries (20.4-62.0%) and remarkable reproducibility (R.S.D. <7.0%). Furthermore, excellent linear dynamic ranges between 0.9 and 16.7 μg/L (r² > 0.9949) and detection limits (0.1-0.5 μg/L) at trace level were also achieved. The application of the proposed analytical approach to analyze triazinic herbicides in ground and superficial water matrices, showed remarkable performance and by using the standard addition methodology the matrix effects are negligible. By comparing the best PU formulation (P₆, 71 μL) with commercial stir bars coated with PDMS (126 μL), recoveries normalized to the polymeric volume up to five times higher (atrazine) were attained. The ability of PU foams to extract the more polar compounds rather than PDMS makes this polymer a very valuable contribution for SBSE.     

分子印迹固相萃取搅拌棒的制备及对复杂样品中双烯雌酚和己烷雌酚的萃取性能

以己烯雌酚为替代模板,利用整体材料的“原位”合成技术制备了分子印迹聚合物,并将其作为固相萃取搅拌棒的涂层(MIP-SBSE)制备了新的搅拌棒。详细考察了分子印迹聚合物制备条件中模板分子及功能单体用量对MIP-SBSE选择性萃取性能的影响,同时利用元素分析、扫描电镜和红外光谱对聚合物进行表征。以双烯雌酚(DS)和己烷雌酚(HS)为目标化合物,将MIP-SBSE与高效液相色谱-二极管阵列检测器联用,建立起复杂样品中DS和HS的分离分析方法。考察了吸附和解吸时间、解吸溶剂、离子强度和样品pH值等萃取条件对MIP-SBSE选择性萃取性能的影响。结果表明,在最佳萃取条件下,MIP-SBSE对DS和HS具有较高的选择性萃取性能,线性范围分别为1.0～400.0 μg/L和5.0～400.0 μg/L,利用氮吹再定容的方法,对DS和HS的检出限(S/N=3)分别可低至0.04和0.14 μg/L。在对实际污水、蜂蜜和牛尿样品的分析中取得了良好的加标回收率,其值为61.3%～120%。所建方法具有简便、高选择性和灵敏等特点,可用于复杂样品中双烯雌酚和己烷雌酚的分析监测。     

Potentialities of polyurethane foams for trace level analysis of triazinic metabolites in water matrices by stir bar sorptive extraction

Polyurethane (PU) foams were applied for stir bar sorptive extraction of five triazinic metabolites (desethyl-2-hydroxyatrazine, desisopropylatrazine, desethylatrazine, 2-hydroxyatrazine and desethylterbuthylazine) in water matrices, followed by liquid desorption and high performance liquid chromatography with diode array detection (SBSE(PU)-LD/HPLC-DAD). The optimum conditions for SBSE(PU)-LD were 5 h of extraction (1000 rpm) and 5% (v/v) of methanol for the analysis of desethyl-2-hydroxyatrazine and 2-hydroxyatrazine, 15% (w/v) of sodium chloride for the remaining compounds and acetonitrile as back-extraction solvent (5 mL) under ultrasonic treatment (60 min). The methodology provided recoveries up to 26.3%, remarkable precision (RSD < 2.4%), excellent linear dynamic ranges between 5.0 and 122.1 μg/L (r² > 0.9993) and convenient detection limits (0.4-1.3 μg/L). The proposed method was applied in the analysis of triazinic metabolites in tap, river and ground waters, with remarkable performance and negligible matrix effects. The comparison of the recoveries obtained by PU and commercial stir bars was also performed, where the yields achieved with the former were up to ten times higher proving that PU is appropriate for analysis at trace level of this type of polar compounds in water matrices.     

Quantitative determination of triclocarban in wastewater effluent by stir bar sorptive extraction and liquid desorption–liquid chromatography–tandem mass spectrometry

Triclocarban is an antimicrobial and antibacterial agent found in personal care products and subsequently is a prevalent wastewater contaminant. A quantitative method was developed for the analysis of triclocarban in wastewater effluents using stir bar sorptive extraction–liquid desorption (SBSE–LD) followed by liquid chromatography–tandem mass spectrometry (LC–MS/MS) by means of an electrospray interface. A stir bar coated with polydimethylsiloxane (PDMS) is placed within a vial containing wastewater effluent and is stirred for an hour at room temperature. The PDMS stir bar is then placed in a LC vial containing methanol and is desorbed in a sonicator bath. The methanol is evaporated to dryness and reconstituted in 75% methanol. Spike and recovery experiments in groundwater that did not contain native concentrations of triclocarban were performed at 0.5 μg/L and were 93 ± 8%. Recoveries in wastewater effluent that were corrected for the background levels of triclocarban were 92 ± 2% and 96 ± 5%, respectively, when spiked with 0.5 and 5 μg/L of triclocarban. The precision of the method as indicated by the relative standard error was 2%. The limit of quantitation was 10 ng/L. The SBSE–LD–LC/MS/MS method was applied to wastewater effluent samples collected from northeast Ohio. Triclocarban was quantitated in all five effluent samples, and its concentration ranged from 50 to 330 ng/L. The described method demonstrates a simple, green, low-sample volume, yet, sensitive method to measure triclocarban in aqueous matrices.     

Development of a sensitive determination method for benzotriazole UV stabilizers in enviromental water samples with stir bar sorption extraction and liquid desorption prior to ultra‐high performance liquid chromatography with tandem mass spectrometry

Benzotriazole UV stabilizers are emerging compounds used in personal care products and can enter surface water after passing through wastewater treatment plants without being removed. Because these analytes are strongly hydrophobic, there is an environmental risk of accumulation in solid matrices and magnification through the trophic chain. In this work, a method based on stir bar sorption extraction with liquid desorption is presented for the extraction of benzotriazole UV stabilizers from water samples. Stir bar sorptive extraction was combined with ultra‐high performance LC with MS/MS detection. All important factors affecting the stir bar sorptive extraction procedure are discussed, and the optimized method was applied to seawater and wastewater samples from Gran Canaria Island, providing good selectivity and sensitivity with LODs and limits of quantification in the range of 18.4–55.1 and 61.5–184 ng/L, respectively. Recoveries between 68.4–92.2% were achieved for the more polar compounds, whereas the recoveries were lower for the two less polar compounds, most likely due to their strong absorption into the polydimethylsiloxane stir bar phase that does not allows the complete desorption. The repeatability studies gave RSDs of between 6.45 and 12.6% for all compounds in the real samples.     

pH-resistant titania hybrid organic-inorganic coating for stir bar sorptive extraction of drugs of abuse in urine samples followed by high performance liquid chromatography-ultraviolet visible detection

An organic-inorganic hybrid titania-hydroxy-terminated silicone oil (titania-OH-TSO) stir bar coating was prepared by sol-gel method. The extraction performance of titania-OH-TSO coated stir bar was evaluated and compared with poly(dimethysiloxane) (PDMS), poly(dimethysiloxane)-divinylbenzene (PDMS-DVB), poly(dimethysiloxane)-β-cyclodextrin (PDMS-β-CD) and C(18) coated stir bar with five polar drugs of abuse including amphetamine (PA), methamphetamine (MA), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA) and ketamine (Ke) as the model analytes. The experimental results revealed that the titania-OH-TSO coated stir bar exhibited highly pH-resistant ability, good preparation reproducibility, superior selectivity and high extraction efficiency for the target compounds. Based on this fact, a new method of titania-OH-TSO coated stir bar sorptive extraction (SBSE) combined with high performance liquid chromatography (HPLC)-ultraviolet visible (UV) detection was developed for the analysis of five drugs of abuse in urine samples. The factors affecting the extraction efficiency of SBSE such as sample pH, desorption solvent, sample volume, extraction time, desorption time, stirring rate and ionic strength were investigated and the optimal extraction conditions were established. Under the optimized conditions, the limits of detection (LODs) for titania-OH-TSO coated SBSE-HPLC-UV determination of five polar drugs of abuse were in the range of 2.3-9.1 μg/L with relative standard deviations (RSDs) ranging from 7.3 to 8.9% (c=300 μg/L, n=6), and all of the target compounds exhibited good linearity over a concentration range of 30-3000 μg/L. The developed method was applied to the determination of amphetamines and Ke in urine samples of drug abusers with satisfactory results.     

固态萃取搅拌棒技术/气相色谱联用分析废水中的痕量爆炸物

制备了以聚醚砜酮(PPESK)为萃取相的新型固态萃取搅拌棒, 建立了一种固态萃取搅拌棒/热解吸器直接热解吸/气相色谱联用分析水样品中痕量爆炸物的新方法. 将萃取搅拌棒放入水样品中完成萃取后, 再直接放入热解吸器中于250 ℃热解吸, 将萃取到搅拌棒上的分析物一次性全部导入气相色谱柱中. 对于硝基苯类爆炸物, PPESK固态萃取搅拌棒的萃取容量比萃取纤维针提高1个数量级以上; 其萃取效率比PDMS固态萃取搅拌棒高2个数量级. 对所测定的7种爆炸物的最低检出限为0.008~0.022 μg/L, 方法的重复性误差(RSD)为6.9%~16%, 在线性浓度范围0.06~10.0 μg/L(除TNT)内, 线性相关系数r为0.9962~0.9998. 在优化的条件下对硝基苯类炸药生产过程中产生的废水进行了分析, 结果表明, 方法的回收率分别为88%~100%(低浓度样品)和61%~88%(高浓度样品), 该方法的重复性误差(RSD)小于11%.     

Determination of trace polychlorinated biphenyls and organochlorine pesticides in water samples through large‐volume stir bar sorptive extraction method with thermal desorption gas chromatography

A fast and sensitive analytical method based on stir bar sorptive extraction technology with gas chromatography and mass spectrometry was developed to simultaneously analyze 18 kinds of polychlorinated biphenyls and 20 kinds of organochlorine pesticides in aqueous samples. A long adsorption time and small sample volume, which are problems encountered in conventional methods of stir bar sorptive extraction, were effectively solved by simultaneously using multiple stir bars for enrichment with sequential cryofocusing and merged injection. Optimized results showed good linear coefficients in the range of 10–500 ng/L and the method detection limits of 0.12–2.07 ng/L for polychlorinated biphenyls and organochlorine pesticides. The recovery ratios of the spiked samples at different concentrations were between 64.7 and 111.0%, and their relative standard deviations ranged from 0.9 to 17.6%. Four types of the studied compounds were determined in Qiantang River water samples, and their contents were between 0.82 and 5.00 ng/L.     

Determination of pesticides in river water using rotating disk sorptive extraction and gas chromatography-mass spectrometry

The rotating disk sorptive extraction (RDSE) technique was applied to the determination of pesticides in aqueous samples. Pesticides of different polarities were considered in this study: chlorpyrifos, diazinon, fenvalarate, cyhalothrin, cypermethrin, lindane and malathion. The sorptive/desorptive behavior of the pesticides was studied using a rotating disk containing a polydimethylsiloxane (PDMS) phase on one of its surfaces. The analyte polarity was a significant factor in the extraction time; shorter extraction times were required for the more apolar pesticides. The optimum variables for the extraction of all analytes were: extraction time of 3 h, sample volume of 25 mL, rotational velocity of the disk 1250 rpm, desorption time of 30 min using methanol. For pesticides with values of Log K_ow > 4, the extraction time can be reduced to 30 min for a quantitative extraction. Under these conditions, recoveries between 76% and 101% were obtained for the target pesticides, and the repeatability of the methodology, expressed as relative standard deviation, was determined to be between 10% and 20%. Additionally, the limits of detection of the analytes were lower than 3.1 μg L⁻¹. The extraction method developed using the RDSE was compared to a stir bar sorptive extraction (SBSE) under the same conditions. It can be observed that the extraction using the rotating disk offers higher recoveries because of its higher PDMS volume and its higher surface area to volume ratio that allows for improved mass transfer.     

Application of a polysiloxane-based extraction method combined with column liquid chromatography to determine polycyclic aromatic hydrocarbons in environmental samples

Silicone rods with a diameter of 1 mm and 10 mm long were used to extract polycyclic aromatic hydrocarbons (PAHs) from water samples and for the rapid screening of highly contaminated waste material. The rods were placed in a 15 ml glass vial for the extraction of the analytes, which involved shaking (300 min⁻¹) the sample for 3 h. After extraction the rods were placed into 250 μl inserts of 2 ml vials filled with 100 μl of an acetonitrile-water mixture (4:1) and desorption was performed with sonication for 10 min. Then the PAHs were determined using LC and fluorescence detection. Recoveries of the rod extraction ranged between 62 and 97% and the detection limits were between 0.1 and 1.2 ng l⁻¹. These results are comparable with those of stir bar sorptive extraction (SBSE). Although the rods are reusable, their low price means they can be discarded if contaminated, eliminating the need for expensive cleaning. One disadvantage compared to SBSE is the longer extraction time needed to reach equilibrium.     

Development of a carbon‐nanoparticle‐coated stirrer for stir bar sorptive extraction by a simple carbon deposition in flame

Stir bar sorptive extraction is an environmentally friendly microextraction technique based on a stir bar with various sorbents. A commercial stirrer is a good support, but it has not been used in stir bar sorptive extraction due to difficult modification. A stirrer was modified with carbon nanoparticles by a simple carbon deposition process in flame and characterized by scanning electron microscopy and energy‐dispersive X‐ray spectrometry. A three‐dimensional porous coating was formed with carbon nanoparticles. In combination with high‐performance liquid chromatography, the stir bar was evaluated using five polycyclic aromatic hydrocarbons as model analytes. Conditions including extraction time and temperature, ionic strength, and desorption solvent were investigated by a factor‐by‐factor optimization method. The established method exhibited good linearity (0.01–10 μg/L) and low limits of quantification (0.01 μg/L). It was applied to detect model analytes in environmental water samples. No analyte was detected in river water, and five analytes were quantified in rain water. The recoveries of five analytes in two samples with spiked at 2 μg/L were in the range of 92.2–106% and 93.4–108%, respectively. The results indicated that the carbon nanoparticle‐coated stirrer was an efficient stir bar for extraction analysis of some polycyclic aromatic hydrocarbons.     

Simple and sensitive monitoring of sulfonamide veterinary residues in milk by stir bar sorptive extraction based on monolithic material and high performance liquid chromatography analysis

A simple, rapid, and sensitive method for the quantitative monitoring of five sulfonamide antibacterial residues (SAs) in milk was developed by stir bar sorptive extraction (SBSE) coupling to high performance liquid chromatography with diode array detection. The analytes were concentrated by SBSE based on poly (vinylimidazole–divinylbenzene) monolithic material as coating. The extraction procedure was very simple, milk was diluted with water then directly sorptive extraction without elimination of fats and protein in samples was required. To achieve optimum extraction performance for SAs, several parameters, including extraction and desorption time, desorption solvent, ionic strength and pH value of sample matrix were investigated. Under the optimized experimental conditions, low detection limits (S/N = 3) quantification limits (S/N = 10) of the proposed method for the target compounds were achieved within the range of 1.30–7.90 ng/mL and 4.29–26.3 ng/mL from spiked milk, respectively. Good linearities were obtained for SAs with the correlation coefficients (R²) above 0.996. Finally, the proposed method was successfully applied to the determination of SAs compounds in different milk samples and satisfied recoveries of spiked target compounds in real samples were obtained.     

聚酰亚胺固相萃取搅拌棒的制备及其在环境水中酚类的分析应用

利用相转换法制备了聚酰亚胺吸附萃取搅拌棒,用5种有机酚作为评价标样,并与现有商品化吸附萃取搅拌棒进行比较。优化了萃取搅拌速度、溶液离子强度、萃取温度、萃取时间以及热解析温度和时间。在最佳实验条件下,100 mL 样品,30% NaCl,在25℃下,经活化5 min 后的聚酰亚胺吸附搅拌棒萃取30 min (800 r/ min),然后300℃热解析4 min,使目标物脱附,再进行色谱分析。目标物在大于两个数量级浓度范围内具有良好的线性(R≥0.9995),定量限(LOQ,S/ N=10)为0.028~0.123μg/ L,重复性为1.6%~9.7%。将SBSE 与气相色谱-质谱联用,对海水、自来水和污水中的酚类进行定性与定量分析,结果表明,聚酰亚胺吸附萃取搅拌棒具有良好的选择性,最高热解析温度350℃,在分析水中痕量极性化合物领域具有广阔应用前景。     

Polydimethylsiloxane/polypyrrole stir bar sorptive extraction and liquid chromatography (SBSE/LC-UV) analysis of antidepressants in plasma samples

A new polymeric coating consisting of a dual-phase, polydimethylsiloxane (PDMS) and polypyrrole (PPY) was developed for the stir bar sorptive extraction (SBSE) of antidepressants (mirtazapine, citalopram, paroxetine, duloxetine, fluoxetine and sertraline) from plasma samples, followed by liquid chromatography analysis (SBSE/LC-UV). The extractions were based on both adsorption (PPY) and sorption (PDMS) mechanisms. SBSE variables, such as extraction time, temperature, pH of the matrix, and desorption time were optimized, in order to achieve suitable analytical sensitivity in a short time period. The PDMS/PPY coated stir bar showed high extraction efficiency (sensitivity and selectivity) toward the target analytes. The quantification limits (LOQ) of the SBSE/LC-UV method ranged from 20 ng mL⁻¹ to 50 ng mL⁻¹, and the linear range was from LOQ to 500 ng mL⁻¹, with a determination coefficient higher than 0.99. The inter-day precision of the SBSE/LC-UV method presented a variation coefficient lower than 15%. The efficiency of the SBSE/LC-UV method was proved by analysis of plasma samples from elderly depressed patients.