土壤中毒性元素As的形态分析及其测定

运用氢化物发生-原子荧光光谱法(HG-AFS)测定土壤中的As(Ⅲ)、 As(Ⅴ)的浸提、萃取分离条件, 以及HG-AFS测定As(Ⅲ)、 As(Ⅴ)的最佳条件. 该方法的线性范围为: 1.0～100 μg/L, 相对标准偏差为: As(Ⅲ): 3.2%～9.5%、 As(Ⅴ): 4.3%～5.2%;回收率为: As(Ⅲ): 104%、 As(Ⅴ): 92%.     

基于响应面法优化的La(OH)3吸附水中As(Ⅲ)和As(Ⅴ)特性对比

以La(OH)_3为原材料,探究其对水中As(Ⅲ)和As(Ⅴ)的吸附性能,并考察吸附剂投加量、p H值、初始浓度及温度对As(Ⅲ)和As(Ⅴ)吸附效果的影响。在单因素初步实验基础上,采用响应面法对La(OH)_3吸附水中As(Ⅲ)和As(Ⅴ)过程进行优化,并研究等温吸附及吸附动力学、热力学特性。结果表明,水中As(Ⅲ)和As(Ⅴ)的最佳去除条件分别为:投加量为0.437g和0.469g,p H值为4.365和3.672,初始浓度为106.716mg/L和108.65mg/L,该条件下As(Ⅲ)和As(Ⅴ)的去除率分别达71.68%和99%以上,且相同条件下As(Ⅴ)的去除效果要优于As(Ⅲ)。等温吸附及动力学拟合结果表明,As(Ⅲ)和As(Ⅴ)的吸附等温线均符合Freundlich模型,相同条件下As(Ⅴ)优于As(Ⅲ)的吸附效果,As(Ⅴ)在200mg/L时的吸附量是As(Ⅲ)的1.43倍,吸附过程均遵循准二级动力学模型,吸附过程为吸热且非自发反应过程。     

超富集植物蜈蚣草对水中As(Ⅲ)吸附行为的研究

采用流动注射-氢化物发生-电热石英管原子吸收光谱法研究了超富集植物蜈蚣草对水中As(Ⅲ)的吸附行为。探讨了蜈蚣草的前处理方法、溶液pH值、吸附时间、吸附剂用量、As(Ⅲ)浓度和溶液体积等因素对蜈蚣草吸附As(Ⅲ)的吸附率的影响。结果表明,以50 mg经2 mol.L-1HCl洗脱处理后的蜈蚣草粉末为吸附剂,在pH为2.0、As(Ⅲ)浓度为20 ng.mL-1、溶液体积50 mL、吸附时间15 min条件下,蜈蚣草对As(Ⅲ)的吸附率可达86.1%,水中残余As(Ⅲ)仅为2.8 ng.mL-1。本法成本低廉、操作简便,可望直接用于地下水中As(Ⅲ)的去除。     

HPLC-HG-AFS测定环境样品中As(Ⅲ)和As(Ⅴ)

建立了高效液相色谱-氢化物发生-原子荧光光谱法测定As(Ⅲ)和As(Ⅴ)的分析方法。通过在载流HCl中加入硫脲使经色谱柱分离后的As(Ⅴ)在线还原为As(Ⅲ),使As(Ⅴ)以As(Ⅲ)的形式与Na BH4进行反应,结果等浓度的As(Ⅴ)和As(Ⅲ)可以获得近似相同的荧光信号,有效地提高了方法检出As(Ⅴ)的能力。     

HPLC–AFS联用测定海产品中砷的形态

建立了高效液相色谱–原子荧光分光光度法测定海产品中无机砷(As V,AsⅢ)、有机砷(DMA,MMA,AsB)含量的方法。样品经含10%(体积分数)HCl的提取液振荡提取、离心分离、二路形态分析预处理、高效液相色谱分离,用原子荧光光度计检测As(Ⅲ),DMA,MMA,As(V);四路条件(过氧化氢氧化和开启紫外灯)形态分析预处理装置处理,高效液相色谱分离,原子荧光光度计测定AsB。As(Ⅲ)线性范围为0～100.00μg/L,r2=0.999 7;DMA线性范围为0～100.00μg/L,r2=0.999 3;MMA线性范围为0～100.00μg/L,r2=0.999 0;As(V)线性范围为0～100.00μg/L,r2=0.999 1;AsB线性范围为0～200.00μg/L,r2=0.999 4。3个样品加标回收率为As(Ⅲ)86.7%～89.4%,DMA 111.2%～117.0%,MMA 109.7%～111.6%,As(V)83.8%～90.7%,AsB 88.3%～90.4%。用该方法测定虾仁(干)5个价态测定结果的相对标准偏差为3.07%～9.93%(n=6)。5个价态的检出限(S/N=2)为As(Ⅲ)0.29μg/L,DMA 0.36μg/L,MMA 0.27μg/L,As(V)0.56μg/L,AsB 1.46μg/L。该方法适用于海产品中As(Ⅲ),DMA,MMA,As(V),AsB含量的测定。     

HPLC-AFS联用测定海产品中砷的形态

建立了高效液相色谱-原子荧光分光光度法测定海产品中无机砷(As V,AsⅢ)、有机砷(DMA,MMA,AsB)含量的方法.样品经含10％(体积分数)HC1的提取液振荡提取、离心分离、二路形态分析预处理、高效液相色谱分离,用原子荧光光度计检测As(Ⅲ),DMA,MMA,As(v);四路条件(过氧化氢氧化和开启紫外灯)形态分析预处理装置处理,高效液相色谱分离,原子荧光光度计测定AsB.As(Ⅲ)线性范围为0～100.00 μg/L,r2=0.9997;DMA线性范围为0～100.00 μg/L,r2=0.9993;MMA线性范围为0～100.00 μg/L,r2=0.9990;As(Ⅴ)线性范围为0～100.00 μg/L,r2=0.999 1;AsB线性范围为0～200.00 μg/L,,r2=0.9994.3个样品加标回收率为As(Ⅲ)86.7％～89.4％,DMA 111.2％～117.0％,MMA 109.7％～111.6％,As(Ⅴ) 83.8％～90.7％,AsB 88.3％～90.4％.用该方法测定虾仁(干)5个价态测定结果的相对标准偏差为3.07％～9.93％(n=6).5个价态的检出限(S/N=2)为As(Ⅲ)0.29 μg/L,DMA 0.36 μg/L,MMA 0.27 μg/L,As(V) 0.56 μg/L,AsB l.46 μg/L.该方法适用于海产品中As(Ⅲ),DMA,MMA,As(V),AsB含量的测定.     

钼酸铵分光光度法测定水质中总磷时砷的干扰消除研究

采用单一影响因素和正交因素水平研究相结合,试验不同形态砷对钼酸铵分光光度法测磷过程的干扰、干扰的主要因素、硫代硫酸钠最佳加入量及最佳显色时间.结果表明不同形态砷的干扰强度依次是,五价砷[As(V)]大于三价砷[As(Ⅲ)],而三价砷[As(Ⅲ)]又远远大于二甲基砷[DMAA].当As(V)浓度小于2.0 mg/L时,显色时间为测定的主要影响因素;当As(V)的浓度为0.1～5.0 mg/L时,考虑到操作以及实际水样中As(V)的含量等因素,选择硫代硫酸钠0.5 mL(40 mg/mL)为最佳量1,5 min为最佳显色时间。     

出口食用甲鱼中有害元素As、Hg的同时测定

建立了微波消解-氢化物发生原子荧光光谱法(HG-AFS)同时测定出口食用甲鱼中As、Hg残留量的方法,并对HG-AFS工作参数及条件进行了优化和选择。As检出限为0.056μg/L,Hg检出限为0.0071μg/L;相对标准偏差As为0.4%(n=11,ρAs=20μg/L),Hg为0.7%(n=11,ρHg=10μg/L);回收率范围为92%~99%。本法已用于出口食用水生活甲鱼中As、Hg残留量的检测。     

高效色谱-电感耦合等离子体质谱法分析海藻类海产品中砷的形态

采用阴(Hamilton PRP-X100柱)阳(Dionex Ionpac CS-10柱)离子交换色谱-电感耦合等离子体质谱联用技术,分别以pH 10.3的20 mmol/L NH4HCO3和pH 2.0的5 mmol/L吡啶溶液为流动相,建立了As(Ⅲ)、As(Ⅴ)、一甲基砷酸(MMA)、二甲基砷酸(DMA)、砷甜菜碱AsB、砷糖PO4、砷糖OH、砷糖SO3、砷糖SO4砷形态的分析方法。采用微波消解法和超声溶剂提取法对不同海域10种紫菜和海带产品进行前处理,对As含量及其化学形态进行分析。实验表明,样品总砷的质量分数为1.7～38.7 mg/kg,样品萃取物中,As糖PO4和As糖OH为As的主要形态,其含量分别占可提取As的6.5%～67.7%和12.9%～86.2%,海带样品萃取物中还有As糖SO3和DMA被检测,其含量分别占可提取As的13.0%～52.1%和5.9%～17.4%。在紫菜和海带海藻类产品中,含As的化合物主要是毒性较低的有机砷。     

As-5、[As5M]-、[As5MAs5]2- (M=Ti,Zr, Hf)的结构和芳香性

用密度泛函理论(DFT)研究了As-5、[As5M]-和[As5MAs5]2- (M=Ti, Zr, Hf)的结构、频率、能量以及芳香性, 详细讨论了体系中不同类型的键和电子如化学键、孤对电子、核电子等对总的核独立化学位移(NICS)的影响. 结果表明, As-5、[As5M]-和[As5MAs5]2-的基态结构分别具有D5h、C5v和D5h对称性, 而且都具有芳香性. As-5 (D5h)的芳香性主要来源于As—As π键和As—As σ键的作用. [As5M]-(C5v)中各种As—M键的NICS分割值占主要优势, 其次是As—As之间形成的σ键. [As5TiAs5]2-(D5h)中, As—As π键的作用占主要优势. [As5ZrAs5]2-(D5h)中, As—As π键对体系总的NICS贡献相对减小, 而As—Zr键的作用增强. [As5HfAs5]2-(D5h)的芳香性主要来自As—Hf键的作用.     

Three new acyclic diterpene glycosides from the aerial parts of paprika and pimiento

Paprika and pimiento are used as vegetables and spices. We have obtained three new acyclic diterpene glycosides, called capsianosides XVII (1), V methyl ester (2) and XIV (3) together with capsianosides I and II from the aerial parts of paprika and pimiento. The structures of these compounds have been established by (1)H- and (13)C-NMR spectra and two-dimensional NMR methods.     

A new neutron activation technique for simultaneous determination of inorganic and total mercury contents in human hair

A simple method for simultaneous determination of inorganic and total mercury contents in human hair by neutron activation analysis (NAA) has been developed. The method is based on the selective extraction of methylmercury from hair by hydrochloric acid. Thus, the residual phase containing inorganic mercury can be determined by NAA. Further, the methylmercury contents in hair samples are easily calculated by subtracting the inorganic mercury contribution from the total Hg simultaneously given by INAA. Several reference materials of human hair, including IAEA hair RM 085 and 086, Chinese hair RMs GBW 09101 and 07601, were analyzed by this method. Our results show that the method is reliable.     

Deposition of JWH-018, JWH-073 and their metabolites in hair and effect of hair pigmentation

Analysis of drugs in hair is often used as a routine method to obtain detailed information about drug ingestion. However, few studies have been conducted on deposition of synthetic cannabinoids and metabolites in hair. The first purpose of this study was to establish and validate an analytical method for detection of JWH-018, JWH-073, and their metabolites in hair, by use of UHPLC–MS–MS, for forensic application. The second purpose was to investigate the distribution of synthetic cannabinoids metabolites in hair and the effect of hair pigmentation, by use of an animal model. For this, JWH-073 was chosen as a representative synthetic cannabinoid. Finally, the developed method was applied to hair samples from 18 individuals suspected of synthetic cannabinoids use. JWH-018, JWH-073, and their metabolites were extracted from hair with methanol. The extract was then filtered and analyzed by UHPLC–MS–MS with an electrospray ion source in positive-ionization mode. Validation proved the method was selective, sensitive, accurate, and precise, with acceptable linearity within the calibration ranges. No significant variations were observed when different sources of both human and rat hair were used. The animal study demonstrated that JWH-073 N-COOH M was the major metabolite of JWH-073 in rat hair, and hair pigmentation did not have a significant effect on incorporation of JWH-073 and its metabolites into hair. In the analysis of 18 authentic hair samples, only JWH-018, JWH-018 N-5-OH M, and JWH-073 were detected, with wide variation in concentrations.     

Enzymatic production of xylooligosaccharides from corn stover and corn cobs treated with aqueous ammonia

A novel method of producing food-grade xylooligosaccharides from corn stover and corn cobs was investigated. The process starts with pretreatment of feedstock in aqueous ammonia, which results delignified and xylan-rich substrate. The pretreated substrates are subjected to enzymatic hydrolysis of xylan using endoxylanase for production of xylooligosaccharides. The conventional enzyme-based method involves extraction of xylan with a strong alkaline solution to form a liquid intermediate containing soluble xylan. This intermediate is heavily contaminated with various extraneous components. A costly purification step is therefore required before enzymatic hydrolysis. In the present method, xylan is obtained in solid form after pretreatment. Water-washing is all that is required for enzymatic hydrolysis of this material. The complex step of purifying soluble xylan from contaminant is essentially eliminated. Refining of xylooligosaccharides to food-grade is accomplished by charcoal adsorption followed by ethanol elution. Xylanlytic hydrolysis of the pretreated corn stover yielded glucan-rich residue that is easily digestible by cellulase enzyme. The digestibility of the residue reached 86% with enzyme loading of 10 filter paper units/g-glucan. As a feedstock for xylooligosaccharides production, corn cobs are superior to corn stover because of high xylan content and high packing density. The high packing density of corn cobs reduces water input and eventually raises the product concentration.     

动态液相微萃取-微波衍生化-气相色谱/选择离子检测-质谱法测定毛发中的苯丙胺类毒品

建立了一种便捷的毛发中4种苯丙胺毒品的检测方法。采用动态液相微萃取法用氯仿提取毛发消解液中的苯丙胺类毒品,然后在微波加热的条件下用N-甲基-双三氟乙酰胺(MBTFA)进行衍生化处理,将反应液直接用气相色谱/选择离子检测-质谱法（GC/SIM-MS）检测。以2-甲基苯乙胺为内标,在空白毛发中添加标准品做标准曲线得到4种苯丙胺类毒品的线性相关系数均不小于0.996。衍生化后4种毒品在毛发中的最小检测限(S/N=3)均为50 pg/mg。4种苯丙胺类毒品在毛发中的添加浓度为5 ng/mg时,5次测定的相对标准偏差（RSD）分别为苯丙胺6.0%,甲基苯丙胺13.9%,3,4-(亚甲二氧基)苯丙胺10.2%,3,4(亚甲二氧基)-甲基苯丙胺9.2%。应用所建立的方法对苯丙胺类毒品吸食者的毛发进行检测,检出了这4种毒品,毛发样品的最小用量为4.6 mg (约20 cm 长)。该方法灵敏、简便、快速,可用于毛发中低含量苯丙胺类毒品的分析。     

Rapid detection of ketamine and norketamine in rat hair using micropulverized extraction and ultra‐performance liquid chromatography–electrospray ionization mass spectrometry

A new method for the rapid and simultaneous detection of ketamine and its major metabolite, norketamine, in rat hair has been developed by combining micropulverized extraction and ultraperformance liquid chromatography–electrospray ionization mass spectrometry. By using reversed‐phase UPLC, ketamine and norketamine were well separated within 2 min. Using ketamine‐dosed rat hair, the conditions for micropulverized extraction were optimized, and the limits of detection and quantification of the developed method were found to be 1.7 and 5.7 pg/mg hair for ketamine, respectively. The precisions achieved with this method were slightly better than that obtained with conventional acidic methanol extraction method. Using this proposed method, analysis of the washed rat hair could be completed within 16–17 min. This method is expected to be applied for the analysis of the hair samples of not only rats but also ketamine abusers. Copyright © 2009 John Wiley & Sons, Ltd.     

纳米纤维固相萃取柱萃取-高效液相荧光法分析头发皮质醇

采用基于纳米纤维固相萃取的高效液相色谱-荧光测定(HPLC-Flu)法测定头发中的皮质醇水平.以新型纳米纤维萃取柱(PFSPE)提取头发样本浸出液,用100 μL乙醇洗脱,再加入230μL浓H2SO4反应2 min,反应物加水混合后用PFSPE柱提取,最后用50 μL甲醇直接洗脱后注入色谱体系进行分析.此方法的检出限为0.05 ng/g( S/N=3),日内精密度和日间精密度分别低于6.8％和8.9％,平均方法回收率为88.9％.本方法提取过程简便、快速、环保,而且可以准确测定头发样本中的皮质醇水平.     

Determination of testosterone in human hair by gas chromatography-selected ion monitoring mass spectrometry.

A method for the determination of testosterone in human hair by gas chromatography-mass spectrometry using d3-testosterone as internal standard is described. Our method consisted of alkaline digestion, fast liquid-liquid extraction, LH-20 chromatography and derivatization with heptafluorobutyric anhydride. Quantification was achieved by selected ion monitoring of m/z 680 (testosterone) and m/z 683 (d3-testosterone). Our method needed no complex corrections for isotope contributions. The procedure provided a sensitive and specific technique with good accuracy and precision. For the first time, testosterone has been quantified by gas chromatography-mass spectrometry in human hair. The concentrations (median, range, ng g-1 hair) reflected a significant (p = 0.05; t-test) sex difference with 2.7 ng g-1 (2.5-4.2) in male and 1.7 ng g-1 (1.0-3.4) in female hair.     

Microanalysis of the antiretroviral nevirapine in human hair from HIV-infected patients by liquid chromatography-tandem mass spectrometry

Sufficient drug exposure is crucial for maintaining durable responses to HIV treatments. However, monitoring drug exposure using single blood samples only provides short-term information and is highly subject to intra-individual pharmacokinetic variation. Drugs can accumulate in hair over a long period of time, so hair drug levels can provide drug exposure information over prolonged periods. We now report on a specific, sensitive, and reproducible liquid chromatography-tandem mass spectrometry method for measuring nevirapine (NVP), a widely used antiretroviral drug, levels in human hair using even a single short strand of hair. Hair samples are cut into small segments, and the drug is extracted in methanol/trifluoroacetic acid (v/v, 9:1) shaken at 37 °C in a water bath overnight, followed by liquid–liquid extraction under alkaline conditions. The extracted samples are then separated on a BDS-C₁₈ column with a mobile phase composed of 50% acetonitrile containing 0.15% acetic acid and 4 mM ammonium acetate with an isocratic elution for a total run time of 3 min and detected by triple quadrupole electrospray multiple reaction mode at precursor/product ion at 267.0 > 225.9 m/z. Deuterated nevirapine-d5 was used as an internal standard. This method was validated from 0.25 to 100 ng/mg using 2 mg hair samples. The accuracies for spiked NVP hair control samples were 98–106% with coefficients of variation (CV) less than 10%. The CV for incurred hair control samples was less than 7%. The extraction efficiency for incurred control hair samples was estimated at more than 95% by repeated extractions. This method has been successfully applied to analyze more than 1,000 hair samples from participants in a large ongoing cohort study of HIV-infected participants. We also showed that NVP in human hair can easily be detected in a single short strand of hair. This method will allow us to identify drug non-adherence using even a single strand of hair.     

GC-MS法测定氧化型染发剂中的苯二胺

建立了气相色谱-质谱同时测定氧化型染发剂中邻苯二胺、间苯二胺和对苯二胺的方法。以乙酸乙酯提取氧化型染发剂中苯二胺,用气相色谱-质谱方法进行定性和定量分析。该方法对氧化型染发剂中的3种苯二胺的检出限为20 mg/kg,线性范围为0.2~10 mg/L,线性相关系数为0.999 2~0.999 9。方法的回收率为75%~110%,满足氧化型染发剂中3种苯二胺检测的需要。