便携式X射线荧光光谱法同时测定氧化锌富集物中锌铁氯镉砷

氧化锌富集物的进口能弥补我国锌矿资源的不足,但要求ZnO>50%、Fe<10%、Cl<8%、Cd<0.25%、As<0.6%。目前常采用YS/T 1171.1～10-2017《再生锌原料化学分析方法》检测氧化锌富集物中锌铁氯镉砷含量,该系列检测方法均需要繁琐的湿法样品前处理,测量过程较为冗长,不能满足氧化锌富集物大量进口时快速通关的需求。故实验建立了采用便携式X射线荧光光谱法(PXRF)同时测定氧化锌富集物中锌铁氯镉砷的方法。采用YS/T 1171.3-2017和YS/T 1171.5-2017方法对氧化锌富集物样品进行定值,然后选取21个含量具有梯度的氧化锌富集物样品作为校准样品,建立起各元素X射线荧光强度值与含量的校准曲线。各曲线相关系数在0.8164～0.9999,方法检出限为0.013%～1.95%,各元素的相对标准偏差(RSD,n=11)均小于0.05%。采用本方法和化学方法分别检测氧化锌富集物样品,各元素的本方法检测值与化学分析方法检测值的相对误差均小于20%。本方法能应用到口岸现场进口氧化锌富集物快速筛查,检测一个样品仅需1分钟测量时间,极大地加快了进口氧化锌富集物通关速度。     

鲁米诺-过氧化氢体系流动注射化学发光法测定痕量钌

1　引　　言钌是贵金属之一 ,在地壳中的平均含量很低 ,即使富集在某些矿床中 ,其实际含量也不高。因此 ,测定时要求采用高灵敏度的测定方法和特效的分离富集技术。目前多采用光度法 ,如催化光度法、荧光光度法等。化学发光分析法具有很高的灵敏度。曾报道有Luminol 溴酸钠 羟基化学发光体系测定痕量钌 ,Luminol Tritonx 10 0 Ru化学发光体系测定微量钌等都获得了成功。流动注射化学发光法具有样品与反应剂的混合过程 ,化学发光的反应过程以及检测过程都在流动体系中连续进行的特点 ,实现了在线检测。采用微型锥形柱 ,以VS Ⅱ型阴离子…     

毛细管电泳场放大进样化学发光检测10-16mol/L水平钴(Ⅱ)

激光诱导荧光（LIF）以其灵敏度高及应用范围广等特点成为单分子检测的主要手段[1]. 但LIF除了仪器昂贵外, 还需对非荧光物质采用柱前或柱后衍生引入荧光团, 且该法易受拉曼散射、瑞利散射和溶剂噪音的影响, 产生高背景干扰. 化学发光（CL）检测灵敏度高, 光学系统简单、无须外加光源及分光系统, 背景低, 避免了杂散光和光源不稳定性的影响. 这些优异性能使其有可能成为毛细管电泳（CE）中的一种超灵敏检测手段. 关于毛细管电泳在线化学发光检测, 本研究组曾提出一种新的试剂混合模式[2], 并设计了一种新颖的检测接口[3], 降低了噪音, 显著提高了信噪比. 场放大进样在线富集技术可用于提高检测灵敏度, 其对有机化合物[4~6]及金属配合物[7]等方面的研究已有报道. 浓缩因子达到1 500[8]. 我们系统地研究了场放大进样对金属离子的富集作用后发现, 所研究的金属离子如钴（Ⅱ）、铬（Ⅲ）、铜（Ⅱ）及镍（Ⅱ）等的浓缩因子可达到104～106.     

基于涡流色谱技术的在线固相萃取/高效液相色谱-荧光检测法结合在线稀释快速测定牛奶中5种氟喹诺酮抗生素残留

建立了牛奶中环丙沙星、达氟沙星、恩诺沙星、沙拉沙星和二氟沙星残留量的快速测定方法。牛奶样品经0.2%三氯乙酸-乙腈(90∶10)沉淀蛋白后,直接进样分析,采用涡流色谱柱作为在线固相萃取柱,通过双梯度液相色谱的左泵结合大体积进样方式对目标分析物进行富集和净化,利用在线100μL定量环中的强洗脱溶剂快速转移目标分析物,并以右泵作为在线稀释泵和分析泵,通过柱头浓集作用改善分离效果。通过荧光检测,方法检出限为0.01~0.13μg/L,远低于欧盟规定限量,且在一定浓度范围内,方法的线性较好,加标回收率为75.9%~95.7%。该方法简便、快速、灵敏度较高,适用于牛奶样品中环丙沙星等5种兽药残留的快速检测。     

分子印迹荧光探针在农药检测中的应用进展北大核心CSCD

分子印迹聚合物由于可特异性地从样品溶液中富集目标物,已被广泛应用于粮食、果蔬等食品以及水、土壤等环境中农药的提取和检测.将分子印迹技术和量子点修饰技术相结合形成的分子印迹荧光探针,可以实现对目标物的高灵敏快速检测.据此,对分子印迹技术的原理、制备方法及应用进行了概述,并进一步阐述了量子点修饰的分子印迹荧光探针在农药检测中的应用和展望.     

在线富集二维毛细管电泳分析新体系检测尿样中药物及对映体

将在线富集技术同二维(2D)毛细管电泳(CE)分离相结合同时提高复杂样品中痕量组分的分离度和检测灵敏度.毛细管区带电泳(CZE)作为第一维,分析物根据淌度不同进行分离,第一维流出组分进入第二维毛细管,根据分配系数不同进行胶束电动毛细管色谱(MEKC)分离.采用阳离子选择性耗尽进样(CSEI)在柱预富集,延长进样时间,增大进样量;同时在二维毛细管接口处采用动态pH联接/胶束扫集在线富集技术不仅避免第一维分离组分在接口处扩散,还可进一步压缩样品区带.同常规电动进样CE分离相比,该在线富集二维分离技术的分离能力远远高于一维CZE或MEKC分离,富集倍数达到(0.5～1.2)×104.该法成功应用于人体尿样中四种药物及对映体的分析测定,浓度检出限为0.1～0.3μg/L.进一步研究了人体尿样中四种药物24h内的药代动力学规律.     

X射线荧光光谱法测定重稀土氧化物富集物中稀土元素含量

建立了测定重稀土氧化物富集物中稀土元素的X射线荧光光谱法。采用人工合成标准样品,按照样品与甲基纤维素质量1∶9的比例,用甲基纤维素稀释粉末压片制样,用X射线荧光光谱法测定重稀土氧化物富集物中的稀土元素含量。以D. Jongh数学模式对谱线干扰和基体效应进行校正。15种稀土元素测定结果的相对标准偏差为0.126%～3.654%(n=10),样品的测定值与计算值基本一致,回收率为94.00%～108.00%。其中La_2O_3,CeO_2,Pr_6O_(11),Nd_2O_3等轻稀土氧化物的检出限为0.11～0.22 mg/g。该方法简便快速、结果准确,能满足重稀土氧化物富集物中各稀土元素检测要求。     

XRF/EDTA滴定法测定钐铕钆富集物样品稀土总量

采用X射线荧光光谱(XRF)法测定钐铕钆富集物的平均摩尔质量;用EDTA滴定法测定钐铕钆富集物中的稀土总量。方法的标准偏差为0．13％,相对标准偏差为0．14％,所得结果与重量法结果基本一致。     

对氨基偶氮苯印迹聚合物的吸附特性及在痕量检测中的应用

采用本体聚合法以α-甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂合成了对氨基偶氮苯的分子印迹聚合物,成功分离了印迹分子和结构相似物甲基橙,并考察了流动相组成、pH、温度和流速对分离效果的影响。用静态吸附法和Scatchard分析考察了对氨基偶氮苯在印迹聚合物上的结合特性。建立了一种在线富集痕量对氨基偶氮苯的分析方法,回收率85%以上。样品只需要过滤处理就可用于富集检测,实现了快速的痕量分析。     

流动注射预富集─石墨炉原子吸收联用测定海水中痕量钼

用二乙基二硫代氨基甲酸钠作络合剂、乙醇作洗脱液的流动注射固相吸附萃取预富集─石墨炉原子吸收联用测定海水中痕量钼。设计了以固定体积取样法为基础的预富集装置。考察了实验参数对分析性能的影响。本法能在线分离干扰、富集被测物,当样品上柱体积为1.35mL时,富集倍数为13.3倍,检测下限为0.027μg/L,用于测定海水等标样中钼含量,精密度较好。     

Rapid and sensitive determination of polycyclic aromatic hydrocarbons in atmospheric particulates using fast high-performance liquid chromatography with on-line enrichment system

A method using on-line enrichment and fast high-performance liquid chromatography (HPLC) with fluorescence detection has been developed and validated for the determination of polycyclic aromatic hydrocarbons (PAHs) in atmospheric particulate samples. The evaporation step for sample preparation can be eliminated since this system allows the injection of 1000microL of sample solution. PAH recoveries were between 87% and 120% for spiked atmospheric particulate samples. The limit of detection was 0.02-0.23ng/mL (signal/noise ratio=3.3). There was good linear correlation between HPLC peak area and PAH concentration, with a linear range of 0.4-40ng/mL and correlation coefficients >0.997. Furthermore, compared to conventional approaches that include an evaporation step, the method proposed is acceptable for detecting PAHs in atmospheric particulate samples.     

Liquid-liquid-liquid microextraction for the enrichment of polycyclic aromatic hydrocarbon metabolites investigated with fluorescence spectroscopy and capillary electrophoresis

The extraction and pre-concentration of phenol, 2-naphthol, and several hydroxyl polycyclic aromatic hydrocarbon (PAH) metabolites were investigated, using liquid-liquid-liquid microextraction (LLLME). The PAH metabolites are a very important class of compounds, and they have not been investigated previously by LLLME. For several of the hydroxyl PAH metabolites, the enrichment factors were small when using LLLME with an alkaline acceptor phase. Changing the acceptor phase to 1-octanol, which gave a two-phase system, improved the enrichment factors significantly for several of the hydroxyl PAH metabolites. For example, the enrichment factor was improved by a factor of 68.5 for 3-hydroxybenzo[a]pyrene. Enrichment factors were investigated as a function of time and stirring rate. At about 55 min the enrichment factor reached a maximum for the two-phase system and at approximately 75 min for the three-phase microextraction system. However, a 30 min extraction time was used for most of the experiments. Also, fluorescence spectroscopy was used to determine the enrichment factors and the mass distribution of the solute between the phases. Fluorescence spectroscopy was very effective in determining the very small concentrations of the solute in the various phases. In addition, capillary electrophoresis and LLLME were combined to demonstrate the substantial enrichment of 2-naphthol by combining these two approaches.     

Analysis of nitrated polycyclic aromatic hydrocarbons by liquid chromatography with fluorescence and mass spectrometry detection: air particulate matter, soot, and reaction product studies

Polycyclic aromatic hydrocarbons (PAH) and their nitrated derivatives (nitro-PAH) are environmental pollutants which pose a threat to human health even at low concentration levels. In this study, efficient analytical methods for the analysis of nitro-PAH and PAH (extraction, clean-up, chromatographic separation, and spectrometric detection) have been developed, characterized, and applied to aerosol samples. The separation and quantification of 12 nitro-PAH was carried out by reversed-phase high performance liquid chromatography (HPLC), on-line reduction, and fluorescence detection. The detection limits were in the range of 0.03–0.5 g L^–1 (6–100 pg in the investigated sample aliquots), and the recovery rates from soot samples were 70–90%. Nitro-PAH and PAH concentrations have been determined for different types of soot and for urban, rural, and alpine fine air particulate matter (PM2.5). For the first time, trace amounts of nitro-PAH have been detected in a high-alpine clean air environment. The on-line reduction and fluorescence technique has been complemented by atmospheric pressure chemical ionization time-of-flight mass spectrometry (APCI-TOF-MS). The MS detection allowed the analysis of partially nitrated and oxygenated PAH in laboratory studies of the heterogeneous reaction of PAH on soot and glass fiber substrates with gaseous nitrogen oxides and ozone. It led to the tentative identification of a previously unknown nitrated derivative of the particularly toxic PAH benzo[a]pyrene (BaP-nitroquinone), and provides the first experimental evidence that PAH-nitroquinones can be formed by reaction of PAH with atmospheric photooxidants.     

Mass distribution for the microextraction of polycyclic aromatic hydrocarbon metabolites investigated with fluorescence spectrometry

Mass-balance data were acquired using fluorescence spectrometry for 2-naphthol and three polycyclic aromatic hydrocarbon (PAH) metabolites using liquid-liquid-liquid microextraction and liquid-liquid microextraction systems. The PAH metabolites are very important biomarkers, and there has been no previously reported mass-balance data on these compounds with microextraction systems. In addition, the effects of two solvent systems used in the preparation of donor and acceptor phases were investigated. The effects of the solvent systems on the partitioning process were compared. The mass balance results showed that significant amounts of the hydrophobic metabolites were held in the pores of the microfiber in both the three-phase and two-phase microextraction systems. Based on the mass-balance data, a new enrichment factor was defined as the concentration of the solute trapped in the pores of the fiber divided by the initial concentration of the solute in the donor phase. Because of the relatively large amount of the solute in the pores, it is envisioned that the solutes could be easily extracted from the pores, the extraction solvent concentrated, and further separated by capillary electrophoresis or characterized by solid-matrix phosphorescence, solution fluorescence, or mass spectrometry.     

First field application of a thermal desorption resonance-enhanced multiphoton-ionisation single particle time-of-flight mass spectrometer for the on-line detection of particle-bound polycyclic aromatic hydrocarbons

The on-line analysis of single aerosol particles with mass spectrometrical methods is an important tool for the investigation of aerosols. Often, a single laser pulse is used for one-step laser desorption/ionisation of aerosol particles. Resulting ions are detected with time-of-flight mass spectrometry. With this method, the detection of inorganic compounds is possible. The detection of more fragile organic compounds and carbon clusters can be accomplished by separating the desorption and the ionisation in two steps, e.g. by using two laser pulses. A further method is, using a heated metal surface for thermal desorption of aerosol particles. If an ultraviolet laser is used for ionisation, a selective ionisation of polycyclic aromatic hydrocarbons (PAH) and alkylated PAH is possible via a resonance-enhanced multiphoton-ionisation process. Laser velocimetry allows individual laser triggering for single particles and additionally delivers information on aerodynamic particle diameters. It was shown that particles deriving from different combustion sources can be differentiated according to their PAH patterns. For example, retene, a C₄-alkylated phenanthrene derivative, is a marker for the combustion of coniferous wood. In this paper, the first field application of a thermal desorption resonance-enhanced multiphoton-ionisation single particle time-of-flight mass spectrometer during a measurement campaign in Augsburg, Germany in winter 2010 is presented. Larger PAH-containing particles (i.e. with aerodynamic diameters larger than 1 μm), which are suspected to be originated by re-suspension processes of agglomerated material, were in the focus of the investigation. Due to the low concentration of these particles, an on-line virtual impactor enrichment system was used. The detection of particle-bound PAH in ambient particles in this larger size region was possible and in addition, retene could be detected on several particles, which allows to identify wood combustion as generic source of these particles. The observed diurnal distribution of these larger particles, however, support the origin by traffic induced re-suspension of sedimented/agglomerated material.     

Polyurethane foam chips combined with liquid chromatography in the determination of unmetabolized polycyclic aromatic hydrocarbons excreted in human urine

A method suitable for the determination of unmetabolized polycyclic aromatic hydrocarbons (PAHs) excreted at trace levels (ng/L) in human urine for the monitoring of exposure of the general population to PAH contamination was developed. PAHs were determined, after enrichment by solid-phase extraction on polyurethane foam (PUF) chips, by HPLC with fluorescence detection. Different parameters affecting analyte extraction to the PUF, including urine salting-out and organic additives, and optimization of conditions for clean-up and desorption have been investigated. Optimized conditions were 40 mL acidified urine sample, added with magnesium sulfate, tetrahydrofuran and a 2 cm3 PUF chip, and extracted by shaking at 30 rpm for 1 h at ambient temperature. Desorption was performed, after a clean-up step with diluted sodium hydroxide, using a small amount of diethyl ether. The recovery of PAH congeners from spiked urines was >90% in the 2-100 ng/L range; the detection limit was 0.1-0.5 ng/L, depending on the considered PAH congener; day-to-day precision, at 50 ng/L native PAH content, was CV = 10-20%. The proposed technique provides a simple, economical and effective procedure for the determination of trace amounts of unmetabolized PAHs excreted in human urine spot samples.     

Column-switching high-performance liquid chromatographic detection of pholcodine and its metabolites in urine with fluorescence and electrochemical detection.

A sensitive and selective method for the detection of pholcodine and its metabolite morphine in urine using high-performance liquid chromatography is described. It involves on-line clean-up of urine on a trace enrichment column packed with a polymeric strong cation-exchange material. Pholcodine and its metabolites were separated on two analytical columns with different selectivities. Pholcodine was detected by a fluorescence detector and morphine was detected electrochemically. One system, based on reversed-phase chromatography, applied a polystyrene-divinylbenzene column and gradient elution. The other system was based on normal-phase chromatography with a silica column and isocratic elution. Morphine was confirmed to be a metabolite of pholcodine by reversed-phase chromatography and electrochemical detection. Two unidentified metabolites of pholcodine were separated from pholcodine by normal-phase chromatography and detected by fluorescence detection.     

On-line liquid chromatography – gas chromatography for automated clean-up and analysis of polycyclic aromatic hydrocarbons

A fully automated system, comprising a liquid chromatograph (LC) coupled on-line to a gas chromatograph (GC) by means of a loop interface, has been constructed for clean-up and analysis of polycyclic aromatic hydrocarbons (PAH). An autosampler was utilized for sample injection into the LC. By the use of a back-flush technique in conjunction with an ordinary analytical aminopropylsilica column, PAH could be isolated by LC: a concurrent solvent evaporation injection technique was then used for on-line transfer of the PAH fraction to the GC, where the PAH analysis was completed. Compared with ordinary off-line LC clean-up followed by GC analysis, the sensitivity has been increased by a factor of 50–100, yielding a detection limit for individual PAH of a few nanograms per sample when using flame ionization detection. Further, irreproducible losses of low molecular weight PAH as a result of solvent evaporation steps in off-line clean-up procedures have been eliminated. Reproducibility of retention times and relative peak areas is high, facilitating automatic peak identification and calculation of concentrations, and the system can thus be used for automatic sample evaluation. The total time required for clean-up and analysis is only 1.5 hours, and the demand on personnel time for the analysis of PAH has been drastically reduced. The technique has been demonstrated with samples of urban air and of used automobile engine lubricating oil.     

Determination in soils of PAH produced by combustion of biomass under different conditions

Summary The nature and concentrations in soils of polynuclear aromatic hydrocarbons (PAH) generated by combustion of pine biomass under different conditions was determined by gas chromatography-mass spectrometry after their enrichment by a simple clean-up procedure. The patterns of pyrogenic PAH, presumably generated by thermal aromatization of biogenic precursors, vary for each sample. When burned at moderate temperature for a long period of time the most abundant homologues generated were alkylated derivatives of naphthalene, whereas phenanthrene alkyl derivatives were predominant after a forest wildfire, where higher temperatures are reached in less time. More condensed PAH included in well-known priority pollutant lists were detected only in minor amounts. No long persistence of PAH was observed in some soil samples analysed.