固相萃取/在线热解吸-气相色谱法分析水样中苯系物

制备了Fe/Si O2/PDMS颗粒填充固相萃取柱,并建立了固相萃取/在线热解吸-气相色谱联用测定水样中痕量苯系物的分析方法。采用电磁感应加热技术在线热解吸固相萃取柱富集的苯系物,并直接引入气相色谱进样口进行分离定量。各苯系物在0.1~20 ng/L范围内线性关系良好,其相关系数(r)为0.999 2~0.999 6,对1 ng/L各苯系物测定的相对标准偏差(RSD,n=11)为2.0%~4.4%,检出限为0.03~0.05 ng/L。     

基于磁性活性炭的分散基质固相萃取-高效液相色谱检测水中双酚A

建立了一种以磁性分散基质固相萃取为预处理技术,结合高效液相色谱检测水样中双酚A的分析方法。制备磁性活性炭作为吸附材料,可以实现吸附材料与水相的彻底、简便的分离。方法的优化条件:吸附时间为15 min、0.5m L丙酮为洗脱剂,洗脱时间为2 min,水样的pH为4,加入25 g/L NaCl。在优化条件下,BPA检出限为0.02μg/L,线性范围为0.05~10μg/L(r=0.9995)。     

磁性Fe3O4@SiO2-SH的制备及环境水体中汞的富集与分析

制备了一种新型的磁性纳米吸附剂—巯基修饰的Fe3O4@Si O2,并将其用作固相萃取剂从环境水样中富集痕量Hg2+,采用原子荧光分光光度计测定富集后的Hg2+。研究了吸附剂用量、p H、平衡时间、洗脱条件及吸附剂重复使用次数对Hg2+回收率的影响。利用该磁性固相萃取方法建立了标准曲线,并用于测定实际水样中的Hg2+含量。方法的检测限为0.1 ng/L,加标回收率为95%~104%,相对标准偏差0.1%~0.6%。     

离子液体-超声辅助-固相萃取法提取富集急性子药材中的4种凤仙萜四醇皂苷

建立了一种绿色、快速、高效萃取和富集中药急性子中4种凤仙萜四醇皂苷的方法。采用离子液体并结合超声辅助萃取急性子中的化学成分,利用固相萃取小柱富集提取液中的凤仙萜四醇皂苷。通过考察离子液体种类及用量、p H值、超声时间、固相萃取剂和洗脱剂等实验条件对提取率的影响,确立了最优萃取剂为[C6mim]Br,最优萃取条件:萃取剂用量为0.9 m L,提取液p H=7.0,超声为30 min,最优富集条件:固相萃取小柱填料为0.9 g CHP20/P120,上样流速为1.5 m L/min,洗脱剂为1.5 m L甲醇。在最优条件下,4种凤仙萜四醇苷加标回收率在92.1%~108.2%之间,相关系数范围为0.9945~0.9975,检出限范围为1.8~4.5μg/m L,RSD3.9%。本方法与传统回流提取方法提取效果接近,可准确测定急性子中4种凤仙萜四醇苷含量。     

流动注射在线吸附预富集-冷蒸气原子荧光法测定矿泉水中的痕量无机汞

研究了聚四氟乙烯管编结反应器(KR)在线吸附预富集技术与冷蒸气原子荧光联用测定矿泉水中痕量无机汞的方法.Hg2+与DDTC在线形成Hg2+-DDTC络合物并吸附在KR内壁上,采用电磁感应加热技术,用20% (V/V) HNO3在线加热洗脱并氧化预富集于KR内壁上的Hg2+-DDTC.洗脱液与KBH4溶液反应生成蒸气态汞,直接用冷蒸气原子荧光联用技术检测.20%(V/V)HNO3作为洗脱液的同时也为氢化发生提供了酸性介质.本方法未使用常用的有机洗脱液,具有操作简单和环保等优点.每小时可分析30个样品,最大吸附倍数为35倍,样品分析精密度RSD为2.2%(n=11),检出限(3σ)为2.0 ng/L.     

一种高选择性汞(Ⅱ) 吸附剂的制备和应用

利用两步反应法制备了溴联苯三酚红功能性硅胶(BPRSG),并通过静态平衡方法研究了该功能性硅胶对多种性质相近的金属离子的选择性吸附性能,考察了溶液pH值和搅拌时间对Hg?吸附率的影响。结果表明,在pH=7.0时,该固相萃取剂对Hg(Ⅱ)有特异的选择性吸附,可以实现与Pb(Ⅱ),Co(Ⅱ),Mn(Ⅱ),Zn(Ⅱ),Cu(Ⅱ),Cd(Ⅱ),Ni(Ⅱ)等金属离子的选择性分离,对Hg?的吸附平衡时间为30 min;最大吸附容量为4.80 mg/g。将该吸附剂制成微型固相萃取柱,用动态平衡法研究了柱流速、洗脱剂种类、洗脱速度和各种干扰离子对分离富集Hg(Ⅱ)的影响。在优化条件下,微柱对Hg?的最低富集浓度为10μg/L,富集倍率为170倍,柱容量为0.65 mg/g。20种常见离子不干扰Hg?的吸附,用1.0 mol/L醋酸即可洗脱Hg(Ⅱ),柱子可重复使用。将微柱用于环境水样中Hg?的固相萃取,回收率在95.5%～98.0%之间。     

流动注射在线预富集-高效液相色谱法测定水中的4-壬基酚和双酚A

建立了以香烟过滤嘴作吸附剂,在线固相萃取(SPE)与高效液相色谱(HPLC)联用测定水中双酚A(bisphenol A,BPA)和4-壬基酚(4-nonylphenol,4-NP)的方法。对于高效液相(HPLC)在线固相萃取而言,采用内置香烟过滤嘴的预富集圆形柱来代替传统的高效液相仪中的注射管进样环用于在线固相萃取。通过流动注射仪将样品分析物负载加入到预富集柱中,随后采用V(甲醇):V(H2O)=93:7混合液为洗脱剂对富集的样品分析物进行洗脱。采用Eclipse XDB-C18色谱柱,V(甲醇):V(H2O)=93:7混合液为流动相,流速为1.0mL/min,紫外检测波长为227nm,保留时间定性,外标法定量。双酚A在0.005～0.8mg/L、4-壬基酚在0.04～8.0mg/L范围内,两者峰面积与浓度呈线性关系,相关系数分别为0.9985和0.9983,检出限(S/N=3)分别为2.1和10.0μg/L,富集倍数分别为816和346倍。对标准混合物(BPA:0.2mg/L;4-NP:2.0mg/L)重复测量11次的相对标准偏差为2.3%和1.5%。本方法用于当地河流水样中BPA和4-NP的测定,回收率为93.2%～105.4%。     

纤维管内固相微萃取-原子荧光光度法测定水中痕量As(Ⅴ)

用聚丙烯纤维作为基体,利用高能电子辐照接枝制备了叔铵化纤维,并采用溴代乙烷季铵化得到季铵型离子交换纤维。将制备的季铵型离子交换纤维用于纤维固相微萃取方法中的吸附剂,与原子荧光光度法相结合,建立了一种简单、快速的测定溶液中痕量As(Ⅴ)的方法。研究了溶液pH、流速、溶液浓度对吸附的影响,并对洗脱剂的种类、洗脱剂的流速和体积进行了优化。在最佳反应条件下,As(Ⅴ)的定量限为0.1μg/L,富集因子为50,相对标准偏差为4.5%(n=6)。该方法可测定复杂基质中痕量As(Ⅴ)。     

在线固相萃取/高效液相色谱法测定环境水样中的4种痕量邻苯二甲酸酯

建立了一种在线固相萃取/高效液相色谱测定水样中4种痕量邻苯二甲酸酯(邻苯二甲酸甲酯、邻苯二甲酸乙酯、邻苯二甲酸丁酯和邻苯二甲酸(2-乙基)己酯)的新方法.样品由外加泵注入一根固相萃取小柱上进行富集,再将富集柱切换至高效液相色谱系统中,将富集在固相萃取小柱的邻苯二甲酸酯洗脱至分析柱进行分析.在线固相萃取柱为IonPac(...     

基于离子印迹聚合物微球固相萃取/微波等离子体发射光谱法测定地表水中痕量铅

建立了地表水中痕量Pb~(2+)的离子印迹聚合物固相萃取/微波等离子体发射光谱测定方法(IISPE/MP-AES)。以Pb~(2+)为模板离子,采用皮克林乳液聚合法制备离子印迹聚合物微球(IIPMs),填装成固相萃取柱对样品中Pb~(2+)进行富集。IIPMs的平均粒径为26.6μm,表面分布有丰富的具特异性吸附性能的多孔状结构,等温吸附实验表明其对Pb~(2+)的吸附属于单分子层吸附。通过对IIPMs固相萃取柱的性能及最优富集条件进行考察,样品富集后采用5%HNO_3洗脱,IIPMs固相萃取柱对水中Pb~(2+)的最大富集倍数为250倍,可重复利用12次以上;在最优萃取条件下,方法的检出限为0.26μg/L,实际地表水样的加标回收率为92.4%~98.8%,相对标准偏差(RSD)不大于4.1%。IIPMs固相萃取与MP-AES联用可用于地表水中痕量Pb~(2+)的准确测定。     

Study on the Solid Phase Extraction of Hg(II)‐ABR Chelate with C18 Disks and its Application to the Determination of Mercury in Tobacco and Tobacco Additives

A highly sensitive, selective and rapid method for the determination of mercury based on the rapid reaction of mercury(II) with 5‐(p‐aminobenzylidene)‐rhodanine (ABR) and the solid phase extraction of the colored chelate with C₁₈ disks has been developed. In the presence of pH = 3.5 sodium acetate‐acetic acid buffer solution and Emulsifier‐OP medium, ABR reacts with mercury(II) to form a red chelate of a molar ratio 1:2 (mercury to ABR). This chelate was enriched by the solid phase extraction with C₁₈ disks and eluted the retained chelate from the disks with dimethyl formamide (DMF). The enrichment factor of 50 was achieved. In the DMF medium, the molar absorptivity of the chelate is 1.16 × 10⁵ L.mol^?1.cm^?1 at 540 nm. Beer's law is obeyed in the range of 0.01?3 μg/mL in the measured solution. The relative standard deviation for eleven replicated samples of 0.01 μg/mL level is 1.83%. This method was applied to the determination of mercury in tobacco and tobacco additives with good results.     

Liquid chromatographic--cold vapour atomic fluorescence spectrometric determination of mercury species

Solvent extraction, sonication, and microwave-assisted extractions in the presence of extraction agents (thioacetic acid, citric acid, cysteine, 2-mercaptoethanol, HCl + NaCl, etc.) were tested for the isolation of mercury species. A mixture of 6 M HCl and 0.1 M NaCl was selected as the most suitable extraction agent. The extraction efficiency was about 10% higher and the RSD below 3.3% when microwave-assisted extraction was applied instead of sonication. The liquid chromatography-cold vapour atomic fluorescence spectrometry (LC/CV-AFS) method was optimised and used for separation and determination of inorganic mercury cations and alkylated and arylated mercury species. Isocratic elution at a flow rate of 0.15 mL/min (with a mobile phase containing 0.05% 2-mercaptoethanol (pH = 5) and 7% methanol and with a stepwise increase of methanol content up to 100% MeOH in the 15th min) was used for separation of mercury species on a Hypersil BDS C18 RP column. The limits of detection of the LC/CV-AFS system were estimated as 0.2 microg/L (3%) for MeHg+, 0.07 microg/L (5.3%) for inorganic Hg, 0.06 microg/L (3.4%) for PhHg+, and 0.12 microg/L (4.4%) for EtHg with the corresponding RSDs at 5 microg/L (n = 10) given in parentheses. The concentrations (2-10 mg/kg fresh weight) of total mercury and methylmercury (90-99% of the total mercury) in selected fish obtained by HPLC/CV-AFS were in good agreement (absolute deviations 0.05 mg/kg) but more precise (RSDs <5.4% at 5 mg/L, n = 10) than those determined by GC coupled to an electron capture detector. The RSDs (3.1-8.2% and 4.1-9.0%) of the overall analytical procedure for the determination of total mercury (AMA 254) and methylmercury (HPLC/CV-AFS) were determined for intra-day and inter-day assays, respectively.     

Speciation analysis of mercury by dispersive solid‐phase extraction coupled with capillary electrophoresis

A pretreatment method of dispersive solid‐phase extraction (DSPE) along with back‐extraction followed by CE‐UV detector was developed for the determination of mercury species in water samples. Sulfhydryl‐functionalized SiO₂ microspheres (SiO₂−SH) were synthesized and used as DSPE adsorbents for selective extraction and enrichment of three organic mercury species namely ethylmercury (EtHg), methylmercury (MeHg), and phenylmercury (PhHg), along with L‐cysteine (L‐cys) containing hydrochloric acid as back‐extraction solvent. Several main extraction parameters were systematically investigated including sample pH, amount of adsorbent, extraction and back‐extraction time, volume of eluent, and concentration of hydrochloric acid. Under optimal conditions, good linearity was achieved with correlation coefficients over 0.9990, in the range of 4−200 μg/L for EtHg, and 2−200 μg/L for MeHg and PhHg. The LODs were obtained of 1.07, 0.34, and 0.24 μg/L for EtHg, MeHg, and PhHg, respectively, as well as the LOQs were 3.57, 1.13, and 0.79 μg/L, respectively, with enrichment factors ranging from 109 to 184. Recoveries were attained with tap and lake water samples in a range of 62.3−107.2%, with relative standard deviations of 3.5–10.1%. The results proved that the method of SiO₂−SH based DSPE coupled with CE‐UV was a simple, rapid, cost‐effective, and eco‐friendly alternative for the determination of mercury species in water samples.     

Mercury determination - SPME and colorimetric spot test

A colorimetric method to determine mercury >20 ng (absolute) in eluates of soils, wastes and waste water was developed. For the elution and the analytical determination only 40 min are needed and the determination can be carried out on site. Due to the low Austrian and German regulatory limit levels of mercury (0.01 mg/1000 g solid phase) it needs to be enriched three times before such low concentrations can be detected. This is done by means of SPME (solid phase micro extraction: Z. Zhang, M.J. Yang, J. Pawliszyn, Anal. Chem. 66 (17) (1994) 844; C.L. Arthur, L.M. Killam, S. Motlagh, M. Lim, D.W. Potter, J. Pawliszyn, Environ. Sci. Technol. 26 (1992) 979; R. Eisert, K. Levsen, J. Chromatogr. A 733 (1996) 143), liquid-liquid extraction and by concentrating the coloured mercury complex in a dot on a TLC-plate. This method was developed as a field method for monitoring set limit levels on site. The interference of non-analytes was determined by adding non-analytes to standard solutions. Mercury contents in soil samples were determined with the developed SPME-spot test and by a standardised method (cold vapour atomic absorption spectrometry). Results were comparable.     

浊点萃取-氢化物发生原子吸收光谱法测痕量汞

提出了浊点萃取预富集氢化物发生-原子吸收光谱法测定痕量汞的新方法。详细探讨了溶液pH值、表面活性剂浓度、平衡时间等因素对浊点萃取效果的影响。在优化的实验条件下,该法对汞的富集倍数为20倍,检出限为0.039μg/L,相对标准偏差(RSD)为4.8%(n=11)。所建立的方法用于天然水中痕量汞的测定,分析结果满意。     

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%.     

固相萃取-高效液相色谱法同时测定啤酒中的4种异构化α-酸

建立了固相萃取-高效液相色谱同时测定啤酒中4种异构化α-酸的方法。采用Sep-Pak C18萃取柱,系统研究了啤酒中异构化α-酸的最佳固相萃取条件。选择以2 mL酸化甲醇为洗脱溶剂,萃取前调啤酒样品的pH至2.5。该方法准确可靠,重现性好,4种异构化α-酸的回收率为90.6%～96.4%,相对标准偏差小于4%。异α-酸、二氢异α-酸、四氢异α-酸和六氢异α-酸的最低检测限依次为0.14,0.36,0.33和0.53 mg/L。     

磁固相萃取-高效液相色谱联用测定尿样中的1-羟基芘

采用磁固相萃取-高效液相色谱-荧光检测方法(MSPE-HPLC-FD)分析了尿样中芘代谢物1-羟基芘(1-Hydroxyperene 1-OHP).2mL尿样以0.1 mol/L醋酸钠溶液(pH 4.5)稀释至4 mL,酶水解后,再以0.1 mol/L醋酸钠溶液(pH 5.0)稀释至10mL,采用十八烷基膦酸改性的磁性介孔纳米粒子(50 mg)为萃取介质,对其进行MSPE富集,涡旋萃取1 min,甲醇解吸3min.解吸液经氮气吹干重新定容后,进行液相色谱分析.本方法在0.01～ 1.00 μg/L范围内线性良好(R2=0.9996);检出限为0.001μg/L日内相对标准偏差小于9.7％(n=5),日间相对标准偏差小于12.9％.将本方法应用于多个人体尿液样品中1-OHP含量的检测,结果满意.为确保结果的科学性和可靠性,测定结果用尿肌酐含量进行了归一化.     

Ionic liquids dispersive liquid–liquid microextraction and HPLC‐atomic fluorescence spectrometric determination of mercury species in environmental waters

An ionic liquid (IL) based dispersive liquid–liquid microextraction combined with HPLC hydride generation atomic fluorescence spectrometry method for the preconcentration and determination of mercury species in environmental water samples is described. Four mercury species (MeHg⁺, EtHg⁺, PhHg⁺, and Hg²⁺) were complexed with dithionate and the neutral chelates were extracted into IL drops using dispersive liquid–liquid microextraction. Variables affecting the formation and extraction of mercury dithizonates were optimized. The optimum conditions found were as follows: IL‐type and amount, 0.05 g of 1‐octyl‐3‐methylimidazolium hexafluorophosphate; dispersive solvents type and amount, 500 μL of acetone; pH, 6; extraction time, 2 min; centrifugation time, 12 min; and no sodium chloride addition. Under the optimized conditions, the detection limits of the analytes were 0.031 μg/L for Hg²⁺, 0.016 μg/L for MeHg⁺, 0.024 μg/L for EtHg⁺, and 0.092 μg/L for PhHg⁺, respectively. The repeatability of the method, expressed as RSD, was between 1.4 and 5.2% (n = 10), and the average recoveries for spiked test were 96.9% for Hg²⁺, 90.9% for MeHg⁺, 90.5% for EtHg⁺, 92.3% for PhHg⁺, respectively. The developed method was successfully applied for the speciation of mercury in environmental water samples.     

Determination of Mercury(II) in Drinking Water by Total Reflection X-ray Fluorescence Spectrometry and Liquid–Liquid Microextraction

The total reflection X-ray fluorescence determination of mercury(II) in drinking water at concentrations of 7?×?10^?2 to 3.0?µg/L is reported. The mercury(II) preconcentration protocol includes directly suspended droplet microextraction with benzene as a molecular iodine complex. The proposed approach is highly selective. The elements Cr, Mn, Fe, Co, Ni, Zn, and Pb at concentrations up to 0.1?g/L did not interfere with the extraction of trace mercury(II). The method is characterized by high sensitivity (limit of detection of 21?ng/L) and suitable reproducibility (relative standard deviation of 0.12 for 100?ng/L). The accuracy of the results was confirmed by recovery and the method of standard addition.