静态顶空/气相色谱-质谱联用快速测定茶粉中残留溶剂

在基质改性剂H2O,平衡温度55℃,进样针温度60℃,传输线温度65℃,平衡加热时间30min,顶空气体进样量0.2mL等顶空取样条件下,建立了静态顶空取样,气-质联用技术快速测定茶粉中残留溶剂乙酸乙酯、氯仿的方法。结果表明该方法简单快速、准确度高、重复性好。     

顶空气相色谱法测定头孢氨苄中有机残留溶剂甲醇

采用顶空气相色谱法测定了头孢氨苄中有机残留溶剂甲醇的含量；以0．5mol/L氢氧化钠溶液为溶剂制备供试品溶液，以ChrompackCP-Si 8CB弹性石英毛细管柱为分离柱，研究了盐析效应、顶空加热温度和顶空热平衡时间对甲醇测定的影响；当添加水平为96．0μg时，回收率为98％～104％，测定相对标准偏差RSD为1．2％(n=6)，检出限为0．5mg／L(信噪比为3：1)，甲醇质量浓度为9．6～153．6mg／L时，线性相关系数为0．9999。     

飞秒光学外差光学克尔效应和低频拉曼光谱技术研究离子液体[bmim][PF6]的低频光谱

利用飞秒光学外差光学克尔效应技术获得了咪唑类离子液体1-丁基-3-甲基咪唑六氟磷酸盐([bmim][PF6])体系中反映分子间相互作用的低频光谱. 结果分析中, 利用Brownian振子时间相关函数的精确表达式对光学克尔效应动力学数据中的核振动部分进行模拟, 在时域上获得各个振动组分的时间演化行为, 并进而通过快速Fourier变换获得各个振动组分的频域光谱和总加和光谱. 此外还利用低频拉曼光谱技术测量了离子液体[bmim][PF6]的低频光谱, 并和飞秒光学外差光学克尔效应实验的结果进行对比, 发现两种方法获得的低频光谱相近. 实验结果表明Brownian振子时间相关函数的精确表达式可用来解析离子液体体系中低频振动的时间演化行为.     

顶空气相色谱法同时测定人工牛黄中7种残留溶剂

建立了同时测定人工牛黄中石油醚（60~90 ℃）、丙酮、乙酸乙酯、甲醇、二氯甲烷、乙醇、乙酸丁酯7种残留溶剂的顶空气相色谱分析方法。以Agilent DB-WAX毛细管色谱柱为分离柱,氢火焰离子化检测器检测,内标法定量,并考察了顶空平衡温度、加压时间、平衡时间等对残留溶剂测定的影响。在优化的条件下,7种残留溶剂在选择的浓度范围内线性关系良好,相关系数（r）均不小于0.9993;在高、中、低3个加标水平下,平均回收率为94.7%~105.2%,相对标准偏差（RSD）均不大于3.5%。方法的检出限（LOD）为0.43~5.23 mg/L,定量限（LOQ）为1.25~16.67 mg/L。该方法操作简单、准确灵敏、高效快捷,适用于人工牛黄中7种残留溶剂的同时检测。     

顶空气相色谱法测定卷烟粘合剂中溶剂残留

采用顶空气相色谱法对卷烟粘合剂中11种溶剂残留化学成分进行标准加入法检测分析。采用DB-624毛细管色谱柱(30m×0.32mm,0.25μm)分离,用火焰离子化检测器测定。在优化的柱温和顶空条件下,11种残留溶剂的测定下限(10S/N)均低于0.5μg.g-1,相对标准偏差(n=6)在1.8%～3.3%之间。甲醇、异丙醇和苯三种溶剂的回收率在94.4%～107.7%之间。     

室温离子液体对多种有机溶剂残留的同时顶空分析

利用1-乙基-3-甲基咪唑四氟硼酸盐([Emim][BF4])为顶空溶剂的顶空气相色谱法(HS-GC)快速、准确地分析了药物中的丙酮、四氢呋喃、二氧六环、吡啶及甲苯等有机溶剂残留。采用ZB-1毛细管柱(60m×0.53mm,5.0μm),程序升温方式,顶空瓶平衡温度100℃,平衡时间20min。待测溶剂在所考察的浓度范围内具有良好的线性,平均回收率为90.1%～96.9%;RSD均小于4.2%;检出限分别为0.05,0.07,0.28,0.31及0.04mg/L。室温离子液体作为溶剂使得方法的灵敏度有所提高。     

顶空气相色谱法测定秦龙苦素中的残留溶剂

采用顶空气相色谱法对秦龙苦素中残留的苯、甲苯、对二甲苯、正己烷等有害物质进行分析,并讨论了流速、柱温、平衡温度、平衡时间、抽样次数等因素对测定的影响。分析结果表明,该方法对上述4种有害物质的检测限范围为3-98 μg/L,测定结果的相对标准偏差为0.59%-2.64%,样品的回收率为97.2%-120.0%。方法简便、快速、灵敏、重现性好。     

顶空-气相色谱法测定橄榄油中6种卤化溶剂残留

卤化溶剂残留量是评价橄榄油质量的重要指标之一。国家橄榄油质量标准GB/T 23347-2021中规定了橄榄油中每种卤化溶剂残留量≤0.1 mg/kg、卤化溶剂残留量总和≤0.2 mg/kg,其检验方法是国际油橄榄理事会发布的COI/T.20/Doc. No 8-1990标准方法,该方法操作繁琐、重复性差、自动化程度低,不适于大批量橄榄油样品中卤化溶剂残留量的测定,而目前国家尚未制定橄榄油中卤化溶剂残留量测定的标准方法。该文建立了橄榄油中氯仿、四氯化碳、1,1,1-三氯乙烷、二溴氯甲烷、四氯乙烯和溴仿6种卤化溶剂残留量的顶空-气相色谱法。将橄榄油试样摇匀后,称取2.00 g(精确至0.01 g)于顶空瓶中,立即封盖待顶空-气相色谱仪分析,采用空白初榨橄榄油配制标准工作液,外标法定量。考察了顶空进样器的进样时间、平衡温度、平衡时间对6种卤化溶剂残留量检测的影响,在进样时间3 s、平衡温度90℃、平衡时间30 min时6种卤化溶剂的分析效果较好。结果表明：6种卤化溶剂在0.002～0.200 mg/kg范围内线性关系良好,相关系数≥0.999 1,检出限为0.000 3～0.000 6 mg...     

顶空-气相色谱法测定醋氯芬酸中的残留溶剂

建立了采用顶空-气相色谱法(HS-GC)测定醋氯芬酸中残留溶剂的方法.试验条件:以DB-624(30 m×0.32 mm,1.8μm)为色谱柱,使用氢火焰离子化检测器(FID),柱温为程序升温,顶空平衡温度80℃,平衡时间30 min.结果表明,异丁烯、甲醇、乙酸甲酯和叔丁醇可有效分离,检测限分别为0.013、0.72...     

顶空气相色谱法测定盐酸司他斯汀中6种残留溶剂

建立了顶空气相色谱法(HS-GC)测定盐酸司他斯汀中乙醚、丙酮、异丙醇、四氢呋喃、甲苯与二甲苯6种有机溶剂残留量的方法.样品用二甲基亚砜溶解,在110 ℃加热20 min,使气液平衡,采用氢火焰离子化检测器(FID),以DB-1701(60 m x 0.320 mm,1.00 μm)为分析柱,程序升温测定.在优化的气相...     

血红蛋白在离子液体[BMIM]PF6碳糊电极上的直接电化学

制备了离子液体[BMIM]PF6修饰碳糊电极(CILE), 并对其形貌和电化学行为进行了表征. 采用涂布法利用壳聚糖-皂土有机-无机复合膜将血红蛋白(Hb)固定于CILE电极表面, 利用紫外可见光谱、红外光谱和电化学方法等手段对包埋于膜内的Hb的性质进行了表征. 结果表明, Hb在薄膜内保持了其原始构象与生物活性, 循环伏安实验表明, 在pH=7.0的Britton-Robinson (B-R)缓冲液中, Hb表现出一对峰形良好的准可逆氧化还原峰, 为Hb Fe(III)/Fe(II)电对的特征峰, 对其直接电化学行为进行了研究, 求出式电位为-0.352 V(vs SCE), 电子转移数为0.885, 电荷传递系数为0.578, 表观异相电子转移速率常数为0.149 s-1.     

顶空/气相色谱-质谱法同时测定报纸中14种溶剂残留

建立了同时测定报纸中14种溶剂残留量的顶空/气相色谱-质谱分析法。采用顶空气相色谱技术,以毛细管柱(Agilent HP-INNOWAX,60 m×250μm,0.25μm)分离,选择离子监测模式(SIM)下进行质谱检测。在优化的顶空/气相色谱-质谱分析条件下,14种溶剂残留在2~20μg范围内线性关系良好,相关系数均不小于0.995;方法的定量下限(S/N=10)均小于0.01 mg/m2。加标水平为3.97~16.28μg时,待测物的平均回收率为86.6%~101.8%,相对标准偏差(RSD,n=6)均不高于6.8%。本方法快速、准确、灵敏,适用于报纸中溶剂残留的测定。     

Determination of Gold by Flame Atomic Absorption Spectrometry with Hollow Fiber Liquid Phase Microextraction Using Room Temperature Ionic Liquids

A novel method to preconcentrate gold was developed employing a synergistic enhancement of a room temperature ionic liquid combined with hollow fiber liquid phase micro-extraction with flame atomic absorption spectrometry detection. The method is based on the complexation of gold with dithizone. The formed hydrophobic complex was subsequently extracted into the lumen of a hollow fiber. The organic phase was siphoned into FAAS for the determination. A room temperature ionic liquid and dithizone were used the enhancement reagent and chelating reagent, respectively. The addition of a room temperature ionic liquid led to a five-fold improvement in the extraction of gold. The 1-octanol was immobilized in the pores of the polypropylene hollow fiber as the liquid membrane and was also used as the acceptor solution. Some parameters that influenced extraction and determination were evaluated in detail, such as concentrations of the ionic liquid and dithizone, pH of samples, stirring rates, extraction time, and interferences. Under optimized conditions, a detection limit of 0.9 ng mL^?1 and an enrichment factor of 130 were achieved. The relative standard deviation (RSD) was 3.7% for Au (40 ng mL^?1, n = 5). The proposed method was successfully applied to the determination of gold in certified reference environmental samples and ore samples with satisfactory results.     

静态顶空/气相色谱-质谱法同时测定化妆品中22种有毒挥发性有机溶剂残留

以2015版《化妆品安全技术规范》中规定的常见禁用及限用有毒挥发性有机溶剂为研究对象,建立了静态顶空/气相色谱-质谱法(SHS/GC-MS)同时测定化妆品中22种有毒挥发性有机溶剂(VOC)(二氯甲烷、顺式-1,2-二氯乙烯、反式-1,2-二氯乙烯、2-氯-1,3-丁二烯、三氯甲烷、1,2-二氯乙烷、苯、四氯化碳、三氯乙烯、甲苯、四氯乙烯、氯苯、乙苯、三溴甲烷、间二甲苯、对二甲苯、苯乙烯、邻二甲苯、异丙苯、1,4-二氯苯、1,2-二氯苯、六氯丁二烯)残留的检测方法。试样在80℃下30 min静态顶空,经DB-1柱分离后,采用选择离子监测模式(SIM)进行定性定量分析。优化了顶空、色谱和质谱参数,结果表明:22种VOC在0.5~50 ng/m L浓度范围内均呈良好的线性关系,相关系数均大于0.99,在1.0,2.0,5.0 ng/m L 3个浓度加标水平下的平均回收率为80.3%~102.7%,相对标准偏差(RSD,n=6)为6.4%~9.9%,检出限为0.2~5.0 ng/g。结果表明,该方法简便、灵敏、准确,具有良好的重现性和稳定性,适合于化妆品中22种VOC残留的筛查和确证检测。     

Ionic liquids as stationary phase solvents for methylated cyclodextrins in gas chromatography

Summary Room temperature ionic liquids (RTIL) are molten salts with melting points well below room temperature. 1-butyl-3-methylimidazolium chloride is a typical example of such RTIL. It was used as a solvent to dissolve permethylated-β-cyclodextrin (BPM) and dimethylated-?cyclodextrin (BDM) to prepare stationary phases for capillary columns in gas chromatography for chiral separation. The RTIL containing columns were compared to commercial columns containing the same chiral selectors. A set of 64 chiral compounds separated by the commercial BPM column was tested on the RTIL BPM column. Only 21 were enantioresolved. Similarly, a set of 80 compounds separated by the commercial BDM column was passed on the RTIL BDM column with only 16 positive separations. It is proposed that the imidazolium ion pair could make an inclusion complex with the cyclodextrin cavity, blocking it for chiral recognition. All the chiral compounds recognized by the RTIL columns had their asymmetric carbon that was part of a ring structure. The retention factors of the derivatized solutes were lower on the RTIL columns than those obtained on the commercial equivalent column. The peak efficiencies obtained with the RTIL capillary were significantly higher than that obtained with the commercial column. These observations may contribute to the knowledge of the mechanism of cyclodextrin-based GC enantioselective separations.     

顶空气相色谱-质谱法测定涂料中的5种挥发性有机物

建立了涂料中5种挥发性有机物(VOCs)的顶空气相色谱-质谱(HS/GC-MS)分析方法.对溶剂、平衡温度、平衡时间、GC-MS的分离检测等实验条件进行了优化.涂料样品经N,N-二甲基甲酰胺(DMF)-水(1 :1,体积比)溶解分散,经90 ℃、90 min静态顶空后,通过DB-VRX色谱柱分离和质谱检测,外标法定量....     

Studies on Liquid/liquid Extraction of Copper Ion with Room Temperature Ionic Liquid

Room temperature ionic liquids are regarded as “Green solvents” for their nonvolatile and thermally stable properties. They are employed to replace traditional volatile organic solvents in organic synthesis, solvent extraction, and electrochemistry. In this work, a water immiscible room temperature ionic liquid, 1‐butyl‐3‐methylimidazolium hexafluorophosphate [C₄mim][PF₆], was used as an alternative solvent for liquid/liquid extraction of copper ions. Metal chelators, including dithizone, 8‐hydroxyquinoline, and 1‐(2‐pyridylazo)‐2‐naphthol, were employed to form neutral metal‐chelate complexes with copper ions so that copper ions were extracted from aqueous solution into [C₄mim][PF₆]. The parameters that affect the extraction of copper ions with this biphasic system were investigated. The extraction behavior in this novel biphasic system is shown to be consistent with that of traditional solvents. For example, the extraction with this biphasic system is strongly pH dependent. So, the extraction efficiency of coppers ion from an aqueous phase can be manipulated by tailoring the pH value of the extraction system. Hence, the extraction, separation and preconcentraction of copper ions can be accomplished by controlling the pH value of the extraction system. It appears that the use of ionic liquid as an alternate solvent system in liquid/liquid extraction of copper ions is very promising.     

Electrochemical Determination of Ascorbic Acid in Room Temperature Ionic Liquid BPPF6 Modified Carbon Paste Electrode

A room temperature ionic liquid N‐butylpyridinium hexafluorophosphate (BPPF₆) was used as a binder to make an ionic liquid modified carbon paste electrode (IL‐CPE), which showed good characteristics such as simple preparation procedure, fast electrochemical response and good conductivity. The electrochemical oxidation of ascorbic acid (AA) on the new IL‐CPE was carefully studied. The oxidation peak potential of AA on the IL‐CPE appeared at 109 mV (vs. SCE), which was about 338 mV decrease of the overpotential compared to that obtained on the traditional carbon paste electrode (CPE) and the oxidation peak current was increased for about four times. The electrochemical parameters of AA on the IL‐CPE were calculated with the charge transfer coefficient (α) and the electrode reaction rate constant (k_s) as 0.87 and 0.800 s^?1, respectively. Based on the relationship of the oxidation peak current and the concentration of AA a sensitive analytical method was established with cyclic voltammetry. The linear range for AA determination was in the range from 1.0×10^?5 to 3.0×10^?3 mol/L with the linear regression equation as I_p (μA)=?2.52–0.064C (μmol/L) (n=13, γ=0.9942) and the detection limit was calculated as 8.0×10^?6 mol/L (3σ). The proposed method was free of the interferences of coexisting substances such as dopamine (DA) and amino acids etc., and successfully applied to the vitamin C tablets determination.     

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

Extraction of drugs from complex sample is a crucial step for determination of drugs. However, most of existing extraction methods use poisonous volatile solvents1. The traditional aqueous two-phase system (ATPS) might be an alternative, but most of phase-forming polymers have high viscidity and form an opaque solution. Recently, ionic liquids (ILs) are gaining attention for their potential use as green solvents and possible replacements for common volatile organic solvents2,3. In this work…     

Determination of Copper in Food and Water by Dispersive Liquid-Liquid Microextraction and Flame Atomic Absorption Spectrometry

A new, simple, and rapid ionic liquid based dispersive liquid-liquid microextraction method is reported for the determination of copper with flame atomic absorption spectrometry. The ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate, was used to extract a copper(II)- curcumin complex. The optimum extraction efficiency of copper was obtained after optimization of the ionic liquid volume, pH, centrifugation speed and time, ultrasonic bath time and temperature, and mass of curcumin. The effects of various ions on the recovery of copper(II) were also investigated. The preconcentration factor was 135. In the optimum experimental conditions, the limit of detection and the relative standard deviation were 0.19 microgram per liter and 4.1 percent, respectively. The method was validated by the analysis of certified reference materials and applied to food and water.