在线固相萃取-液相色谱-串联质谱法检测蘑菇中毒患者尿液中痕量α -鹅膏毒肽

建立了在线固相萃取-液相色谱-串联质谱（online SPE-LC-MS/MS）测定蘑菇中毒患者尿液中痕量α -鹅膏毒肽的分析方法。样品经甲酸酸化的乙腈-甲醇（5：1,v/v）沉淀蛋白质,反相液液微萃取去除样品提取液中的有机溶剂,毒素经ODS微柱（5 mm×2.1 mm,5 μm）在线SPE净化,XBridge^TM BEH C₁₈ 色谱柱（150 mm×3.0 mm,2.5 μm）分离,MS/MS测定。采用基于定量环的快速阀切换技术作为在线SPE和LC-MS/MS模块的接口,使得两个分离模块互相独立,无论是流动相还是压力,都不会互相干扰,保证了系统的稳定性;在线系统的精准净化,有效消除了后续质谱检测的基质效应,确保了尿液中痕量水平α -鹅膏毒肽的定性定量检测。尿液中α -鹅膏毒肽在0.1~50 μg/L范围内线性关系良好,相关系数（r ² ）为0.9983;检出限（LOD）为0.03 μg/L;α -鹅膏毒肽的加标（0.1、2.0和20 μg/L）平均回收率为84.3%~91.7%,相对标准偏差（RSD）为3.8%~7.2%。体内鹅膏毒肽代谢迅速,生物基质中痕量水平毒素的检测是其中毒实验室鉴定的主要难题,通过实际样品检测,证明该法操作简单,准确、灵敏;溶剂沉淀蛋白质和反相液液微萃取去除有机相和脂溶性基质的简单操作,可以作为水溶性毒素在线SPE-LC-MS/MS检测时快速且有效的配套前处理方法;基于在线SPE精准净化技术,可以实现尿液中α -鹅膏毒肽的高灵敏度测定（LOD为0.03 μg/L）,解决了中毒时患者体内痕量水平α -鹅膏毒肽定性确证的难题,部分患者α -鹅膏毒肽中毒实验室鉴定的时间可以扩展到90 h以上;同时,痕量水平的定量检测技术,可以为中毒后迅速代谢的α -鹅膏毒肽在体内的剂量反应关系研究提供可靠的技术支撑。     

超临界色谱法测定化妆品中生育酚及α-生育酚乙酸酯

建立了化妆品中4种生育酚异构体及α-生育酚乙酸酯的超临界色谱分析方法。不同基质类型的化妆品经乙腈水溶液-正己烷溶剂体系按不同的添加顺序进行分散、提取、液液分配后,以二氧化碳为流动相,异丙醇-正己烷(1∶1)为改性剂,利用亚乙基桥杂化颗粒色谱柱(Viridis@BEH,250 mm×4.6 mm,5μm)对目标物和样品杂质进行有效分离,用光电二极管矩阵检测器(SFC-PDA)进行测定。系统考察了提取条件和色谱条件对实验结果的影响。结果表明:4种生育酚和α-生育酚乙酸酯的定量下限(S/N=10)分别为50 mg/kg和25 mg/kg,空白基质加标回收率为81.3%~109.5%,相对标准偏差(RSD)不大于12.8%。该方法前处理简单、快速、准确,可用于各类化妆品中4种生育酚异构体及α-生育酚乙酸酯含量的检测。     

在线固相萃取/二维液相色谱法检测婴幼儿配方食品中视黄醇顺反异构体和α-生育酚手性异构体

建立了在线固相萃取/二维液相色谱分离检测婴幼儿配方食品中全反式视黄醇、13-顺式视黄醇和α-生育酚手性异构体的方法。样品经皂化，定容、离心、过滤后进样，经二乙烯基苯与N-乙烯基吡咯烷酮大孔共聚物（HLB）在线固相萃取柱在线净化后，通过切换阀将视黄醇、4种生育酚洗脱至一维色谱柱五氟苯基填料柱（PFP），在一维色谱柱中实现总视黄醇和4种生育酚异构体的分离。再通过捕集柱与中心切换阀将总视黄醇和α-生育酚切割至二维色谱柱，在3,5-二甲基苯基氨基甲酸酯涂敷的手性色谱柱（CND）上实现了全反式与13-顺式视黄醇的异构体分离，以及α-生育酚的d、l手性异构体分离。采用紫外和荧光检测器检测，外标法定量。结果表明：全反式视黄醇、13-顺式视黄醇的线性范围为0.1～5.0 mg/L,d-α-生育酚、l-α-生育酚的线性范围为1.0～30.0 mg/L，相关系数均大于0.999，定量下限分别为53μg/100 g、56μg/100 g、290μg/100 g和340μg/100 g；低、中和高3个加标浓度下的回收率为90.9%～106%，相对标准偏差（RSD）不大于2.8%。该方法可用于乳基婴幼儿配方食品...     

加速溶剂萃取-固相萃取净化-气相色谱-串联质谱法检测茶叶中9种拟除虫菊酯类农药残留

建立了加速溶剂萃取（ASE）-固相萃取净化（SPE）-气相色谱-串联质谱（GC-MS/MS）同时测定茶叶中9种拟除虫菊酯类农药残留的方法。ASE萃取溶剂为丙酮-正己烷（1：1,v/v）,萃取温度为100℃,萃取压力为10 MPa,加热时间为3 min,静态萃取时间为5 min,循环1次,冲洗体积为40%萃取池体积,氮气吹扫100 s。萃取结束后用Cleanert TPT固相萃取柱净化,净化液浓缩定容后,采用GC-MS/MS测定,外标法定量。9种拟除虫菊酯类农药在2~1000 μg/L范围内呈现良好的线性关系,相关系数（r²）均大于0.99,方法检出限为0.2~4.5 μg/kg,定量限为0.8~15.0 μg/kg。在绿茶、红茶空白基质中做加标回收试验,添加水平为0.02、0.1、0.4 mg/kg以及定量限水平,得到的平均回收率为69.87%~110.0%,相对标准偏差（RSD）为0.7%~11.2%。该方法背景干扰低、灵敏度高、重现性好、回收率稳定,适用于茶叶中拟除虫菊酯类农药残留量的检测。     

超高效合相色谱法快速测定保健食品中10种脂溶性维生素

脂溶性维生素作为保健食品重要的功效指标,现有的标准方法存在测定组分少、样品前处理过程复杂、对人员操作能力要求较高等问题,因此建立一种快速、简便、准确,且能同时检测多种常见脂溶性维生素的方法具有重要的现实意义。该研究采用超高效合相色谱(UPC²)建立了同时测定保健食品中维生素A棕榈酸酯、维生素A醋酸酯、维生素E醋酸酯、维生素K₁、α-生育酚、β-生育酚、γ-生育酚、δ-生育酚、维生素D₂、维生素D₃等10种常用脂溶性维生素的方法。样品经含75%二甲基亚砜(DMSO)的水溶液在45 ℃水浴超声15 min破乳,再加入正己烷振摇提取90 min, 3000 r/min离心10 min,取上清液过滤后进行分析。使用LC-Simulator软件对色谱条件进行模拟及优化,选用ACQUITY UPC² Viridis HSS C18 SB色谱柱进行分离,CO₂和乙腈-甲醇(85∶15, v/v)为流动相,梯度洗脱,流速1.9 mL/min,柱温30 ℃,选取10种脂溶性维生素各自的最大吸收波长检测,外标法进行定量。结果表明,10种脂溶性维生素在各自范围内线性关系良好,相关系数(r)均大于0.9997,检出限(LOD)和定量限(LOQ)分别为片剂:0.2~30 μg/g和0.8~75 μg/g,胶囊:0.4~60 μg/g和2~150 μg/g,样品平均加标回收率在96.5%~113.9%之间,RSD均小于4%,精密度、稳定性、重复性测定结果的RSD值也均小于2%。经比较,该方法测定结果与现有的国家食品安全标准基本一致,但该方法简单、快速、灵敏、准确,可满足保健食品中10种脂溶性维生素的检测要求,为保健食品中脂溶性维生素的快速同时检测奠定基础。     

固相萃取-衍生化-气相色谱-质谱联用法同时测定尿液中4种阿片类物质

公安机关用胶体金尿检法对海洛因滥用者的检测常常受到阿片类镇咳药的干扰,使用传统液-液提取法进行实验室检验,操作效率低,灵敏度不高,无法满足公安机关打击涉毒案件的需要。为此,该研究建立了尿液中吗啡、O ⁶ -单乙酰吗啡、可待因和乙酰可待因4种阿片类物质的固相萃取和衍生化技术结合气相色谱-质谱联用（GC-MS）同时检测方法。尿样用磷酸盐缓冲液调节至pH=6后,经MCX固相萃取柱净化,用N -甲基-N -（三甲基硅烷基）三氟乙酰胺（MSTFA）对吗啡、O ⁶ -单乙酰吗啡、可待因进行衍生化,供GC-MS检测。考察了上样和洗脱流速、淋洗液中甲酸体积分数、洗脱液中氨水体积分数、3%（v/v）甲酸甲醇淋洗液体积和固相萃取柱吹干时间对萃取效果的影响。确定上样和洗脱流速1.0 mL/min,淋洗液中甲酸体积分数3%,洗脱液中氨水体积分数5%,3%（v/v）甲酸甲醇淋洗液体积1 mL,吹干时间1 min为最佳条件。在此条件下,4种阿片类物质在0.02~0.8 μg/mL范围内线性关系良好（r ² ≥0.998）,检出限（LOD）为0.0016~0.0039 μg/mL,定量限（LOQ）为0.0054~0.0128 μg/mL,当标准添加水平为0.02、0.1、0.2 μg/mL时,回收率为93.0%~110.3%。该方法结合自动化技术,对固相萃取条件精确控制,操作简便、快速、灵敏、准确,适合尿液中吗啡等4种阿片类物质快速测定,可用于海洛因吸食者的大规模监控,并能准确排除因服用含阿片类镇咳药导致的吗啡胶体金尿检假阳性。     

气相色谱-质谱法测定植物油中8种维生素E及其在芝麻油真伪鉴别方面的应用

建立了气相色谱-质谱（GC-MS）同时测定植物油中α-、β-、γ-、δ-生育酚和α-、β-、γ-、δ-生育三烯酚等8种维生素E的分析方法。植物油样品经甲醇超声提取、浓缩、定容,在分时段选择离子监测（SIM）模式下分离分析,采用外标法进行定量。结果表明,8种维生素E可实现基线分离;在0.01~1 mg/L范围内,所有目标物均呈良好线性关系,相关系数均大于0.99;检出限和定量限分别为0.03~0.25 mg/kg和0.10~0.83 mg/kg;在芝麻油中分别添加10、50和250 mg/kg 3个水平的8种维生素E进行加标试验,平均回收率为87.5%~107.4%,相对标准偏差（RSD）≤ 7.5%。所建立的方法简单、准确、可靠,且灵敏度高,可用于测定植物油中8种维生素E的含量。采用上述方法对芝麻油、大豆油、菜籽油、葵花籽油、花生油、玉米油和棕榈油等7种共75个植物油样品中维生素E的含量进行测定。结果显示,芝麻油与其他6种植物油中的8种维生素E的组成和含量均有显著差异性,因此该方法可作为芝麻油掺入其他植物油的特征鉴定指标。     

加速溶剂萃取-气相色谱-串联质谱法测定茶叶中10种吡唑和吡咯类农药的残留量

建立了加速溶剂萃取(ASE)-气相色谱-串联质谱(GC-MS/MS)法用于测定茶叶中10种吡唑和吡咯类农药残留。ASE萃取压力为1.03×107 Pa,萃取温度为100 ℃,萃取时间为5 min,萃取溶剂为乙酸乙酯-正己烷(1:1, v/v)。萃取循环1次,萃取液浓缩后用Envi-Carb/PSA固相萃取小柱净化,乙酸乙酯-正己烷(1:1, v/v)洗脱。洗脱液浓缩后,用正己烷定容,供GC-MS/MS测定,外标法定量。方法的准确度和精密度均符合残留分析要求。方法的定量限(LOQ)分别为唑螨酯0.003 mg/kg、氟虫腈硫化物0.001 mg/kg、氟虫腈0.002 mg/kg、氟虫腈砜化物0.005 mg/kg、溴虫腈0.002 mg/kg、氟硅唑0.006 mg/kg、野燕枯0.001 mg/kg、吡草醚0.001 mg/kg、吡螨胺0.0003 mg/kg、唑虫酰胺0.005 mg/kg。方法的灵敏度能满足各国有关农药的残留限量要求。     

快速溶剂萃取-气相色谱-串联质谱法同时测定土壤中有机氯及有机磷农药

建立了快速溶剂萃取（ASE）-气相色谱-串联质谱（GC-MS/MS）同时分析土壤中8种有机氯农药（OCPs）和5种有机磷农药（OPPs）的方法。样品由正己烷-丙酮（1：1,v/v）溶液萃取,经无水硫酸钠脱水、氮吹仪浓缩后,采用硅胶（Si）固相萃取小柱进行净化,正己烷-丙酮（1：1,v/v）溶液进行洗脱,然后经HP-5MS色谱柱（30 m×0.25 mm×0.25 μm）分离,在电子轰击电离源下以多反应监测（MRM）模式进行检测,内标法定量。分析结果表明,13种目标物在1.00~100 μg/L范围内线性关系良好,相关系数（R）大于0.995;加标回收率为66.8%~88.4%,能够实现准确定量;日内精密度与日间精密度均小于10%。当取样量为10.0 g时,8种OCPs的方法检出限为0.02~0.04 μg/kg,5种OPPs的方法检出限为0.06~0.12 μg/kg,能够满足土壤农药残留的检测要求。     

柱后还原-高效液相色谱法同时测定调制乳粉中维生素K1和维生素K2

建立了一种同时检测调制乳粉中维生素K₁和维生素K₂的柱后还原-高效液相色谱-荧光检测方法。样品用水溶解，经脂肪酶酶解，2.5 mol/L氢氧化钠溶液和乙醇溶液皂化，正己烷萃取，氮吹浓缩后，用甲醇复溶。通过Xbridge C₁₈色谱柱分离，锌粉还原柱柱后还原，荧光检测器检测，激发波长为326 nm，发射波长为432 nm，外标法定量。结果表明，维生素K₁在0.0025~2.0 μg/mL、维生素K₂在0.01~2.0 μg/mL范围内线性关系良好，相关系数均大于0.999，维生素K₁和维生素K₂的检出限分别为0.07 μg/100 g和0.24 μg/100 g，定量限分别为0.2 μg/100 g和0.8 μg/100 g；方法的加标回收率为80.39%~94.39%，精密度为0.85%~3.98%。该方法灵敏度高，重复性好，结果准确，适用于调制乳粉中维生素K₁和维生素K₂的分析检测。     

Off-line coupling of pressurized liquid extraction and LC/ED for the determination of retinyl acetate and tocopherols in infant formulas

An analytical methodology including pressurized liquid extraction (PLE) as sample treatment to isolate retinyl acetate and tocopherols from infant formulas has been developed. The milk extracts were kept at −18 °C for 30 min and after filtration could be injected directly into the chromatographic system. Thus, a rapid and simple routine control method of these products is possible.

The parameters affecting both the extraction process and the liquid chromatography (LC) system were optimized. PLE was performed using one cycle of extraction during a static time of 5 min. Methanol was chosen as the extraction solvent for a temperature of 50 °C. Chromatographic separation was accomplished using a RP-18 column; the mobile phase used was methanol–water (94:6, v/v) containing 2.5 mM acetic acid/sodium acetate buffer. Electrochemical detection in amperometric mode with a glassy carbon electrode at +1100 mV was applied. The proposed methodology was successfully used for the determination of retinyl acetate, δ-tocopherol, (β + γ)-tocopherol and -tocopherol in different infant formulas. The analytes were evaluated in the same chemical form present in the samples. Recoveries were between 92 and 106%. A certified reference material of milk powder was also analyzed.     

毛细管区带电泳测定液态奶及奶粉中的A2 β-酪蛋白及总β-酪蛋白

β-酪蛋白（β-CN）是牛乳中的主要酪蛋白。它包含13种变异体,其中A2是牛β-CN的主要变异体之一。定量测定A2 β-CN对A2乳制品的评价十分重要。该文建立了对液态奶和奶粉中A2 β-CN及总β-CN分离并定量的毛细管区带电泳（CZE）分析方法。使用熔融石英毛细管（50 μm×30/40 cm有效/总长度）,以50 mmol/L Na₂HPO₄+140 mmol/L柠檬酸+0.2%（质量分数）HPMC+4 mol/L尿素溶液（pH为2.7）作为分离缓冲溶液,在214 nm下检测。总β-CN和A2 β-CN的校准峰面积与其质量浓度间呈良好的线性关系,相关系数在0.9968~0.9997之间,加标回收率为85.5%~106.4%。对两款巴氏奶和两款奶粉中A2 β-CN和总β-CN进行分析,A2 β-CN和总β-CN的日内精密度分别为2.4%~4.7%和2.6%~4.8%,日间精密度分别为4.0%~6.3%和3.9%~6.7%。所建立的CZE方法可分离液态奶及奶粉中的A2 β-CN,并可对A2 β-CN及总β-CN进行定量。通过计算A2 β-CN在总β-CN中的占比来评价A2乳制品的质量,为保护消费者的利益提供了方法依据。     

Hydrothermal Synthesis and Characterization of Perovskite Oxide AgTaO3

The perovskite-type AgTaO₃ crystals were prepared by mild hydrothermal method and determined by powder X-ray diffraction. Rietveld refinement indicates that AgTaO₃ crystallized in an orthorhombic system with the space group Pcmn. The lattice parameters are a=5.5822(1) nm, b=7.8522(2) nm and c=5.5347(1) nm, with α=β=γ= 90.0o. The compound was characterized by scanning electron microscopy(SEM), X-ray photoelectron spectroscopy (XPS), high resolution transmission electron microscopy(HR-TEM) and UV-Vis diffuse reflectance spectrometry (UV-Vis DRS). The photocatalytic activity of AgTaO₃ powder was evaluated by the degradation of Congo red under UV-light irradiation. The result shows that the titled compound has a high photocatalytic activity at room temperature and potential application in photocatalysis.     

Assay of Brain Tocopherols Using High Performance Liquid Chromatography

Abstract

The four natural tocopherols were separated using a μ-Bondapak-NH₂ column. For the analysis of brain tocopherols 5,7-dimethyltocol was used as an internal standard. α-Tocopherylquinone and other tocopherols than α-tocopherol were not detected. Rat cerebral cortex and cerebellum contained 19.3 μmol/g and 11.2 μmol/g of α-tocopherol, respectively. A chromatographic system with a reversed-phase column proved less suitable.     

Computational study of calix[4]arene derivatives and complexation with Zn

High level DFT was applied to study structure and conformational equilibrium of amino and mercaptocalix[4]arenes possessing methylene groups or sulfur atoms at their four junctions. All the calculations point to cone and 1,3-alternate as the most stable conformers for sulfur and methylene bridged compounds, respectively. The presence of four sulfur atoms in place of the methylene bridges can lead to novel features in the complexation with transition metals. The host–guest 1:1 complexes between Zn²⁺ and each conformer of tetraaminothiacalix[4]arene were also investigated at the same DFT level. The four nitrogens of amino groups play a dominant role in the interaction with Zn²⁺ via distorted tetrahedral coordination for 1,3-alternate, or distorted square planar for partial cone and 1,2-alternate. On the other hand, the 2:1 complexes with cone show that the sulfur bridges can also bind Zn²⁺ and contribute to form two sets of five-membered chelated rings with two N donor atoms.     

Determination of vitamin E isomers of grape seeds by high-performance liquid chromatography-UV detection

A simple analytical method for the determination of vitamin E isomers in grape seeds by reversed-phase high-performance liquid chromatography with UV detection is described. The method is based on a solid-liquid extraction separation on an ODS column, and the analytes are monitored at 295 nm with a UV detector. Tocopherols are extracted in n-hexane and directly injected onto the column without using any purification step, such as saponification, prior to the separation and determination. The chromatographic separation of tocopherols is achieved in 12 min with a mobile phase that consists of n-hexane and isopropyl alcohol (99.99:0.01, v/v). The method is reproducible and accurate, with respect to demonstrating a relative standard deviation between 2.57% and 3.30% (n = 10, for 500 ng/mL) and a relative error between 0.84% and 6.54% (n = 10, for 500 ng/mL), respectively. The theoretical limits are estimated as 25 ng/mL for α-tocopherol, 43 ng/mL for γ-tocopherol, and 83 ng/mL for δ-tocopherols. The method is then applied for the determination of tocopherols in grape seeds grown in Turkey. The amounts of tocopherols are calculated by using the standard addition method.     

The simultaneous determination of capsaicinoids,tocopherols, and carotenoids in pungent pepper powder

From nutritional points of view, carotenoids, capsaicinoids, and tocopherols are valuable constituents in pungent peppers. A rapid and reliable high performance liquid chromatography (HPLC) method for the simultaneous determination of phytonutrients in spice red peppers and chili products was developed and validated. The method included simultaneous detection by fluorescence and diode-array detectors. The major capsaicinoids, two tocopherols and 43 carotenoid components, were simultaneously separated, detected, and identified in the appointed pepper powder (containing Capsicum annuum and Capsicum frutescens) for method validation. The separation was performed on a Nucleosil C18 reverse phase column and optimized gradient elution. Resolution ranged between 0.96 and 1.46 with the highest values corresponding to γ-tocopherol and α-tocopherol. The limits of detection and quantification of target compounds ranged between 18.77 and 148.08 ng mL^?1. Recoveries were between 89.83–100.26 and 79.72–88.86% when standard materials were spiked at low and high amounts, respectively. The most sufficient extraction of the different phytonutrients was achieved by mixture of methanol and acetone, although it was only slightly better than the mixture of methanol and acetonitrile. These results suggest that the developed method could be used for rapid, one-step determination of a wide range of phytonutrients in chili and pepper powders.     

液相色谱-大气压化学电离串联质谱法测定婴幼儿配方奶粉中的维生素D

建立了婴幼儿配方奶粉中维生素D的液相色谱-大气压化学电离串联质谱(LC-APCI-MS/MS)分析方法。样品经正己烷和甲基叔丁基醚混合溶液提取,ProElut VDC固相萃取柱净化,Kinetex C_(18)色谱柱分离,采用大气压化学电离(APCI)源、正离子扫描和多反应监测(MRM)模式对维生素D_2和维生素D_3进行检测,内标法定量。结果表明维生素D_2和维生素D_3在5~5 000μg/L范围内均具有良好的线性关系,检出限为2μg/kg,定量限为5μg/kg。在5、10和100μg/kg添加水平下,维生素D_2和维生素D_3的回收率为85.2%~105.3%,相对标准偏差为4.7%~8.1%。该方法简便准确,灵敏度高,适用于婴幼儿奶粉中维生素D的测定。     

安培检测-离子色谱法测定乳品中的微量碘

 用安培检测 离子色谱法检测了乳品中的微量碘。以NaOH作淋洗液 ,直接进样 ,优化了碘的离子色谱分离和测定条件 ,方法的检测限达 1μg/L(3倍信噪比 )。测定了婴儿奶粉、孕产妇专用奶粉和鲜牛奶中的微量碘 ,加标回收率分别为 89 0 % ,86 0 %和 84 1%。