两种微波等离子体炬质谱测定水中铅的对比研究

建立了一种新型的能够灵敏分析水中痕量铅的质谱方法,以微波等离子体炬(MPT)为离子源,可无需样品预处理而直接分析水样。样品经雾化和去溶后由MPT的中心管道引入等离子体,离子由国产的四极杆质谱仪(Q-MS)检测,得到铅的MPT特征质谱。定量结果表明,该方法的检出限为20 ng/L,线性范围为200~1 000 ng/L,相对标准偏差(RSD)为5.3%;所得定量指标优于相同条件下商用的线性离子阱质谱(LTQ-MS)测试结果,且四极杆质谱仪上所得的铅离子特征质谱信号更简单、易归属,无需复杂的多级串联质谱加以确认。这种MPT可与国产质谱仪器相结合发展成为一种低成本的现场检测铅的质谱仪器,在环境监控、饮用水检验等方面具有一定的应用价值。     

电感耦合等离子体质谱测定地质样品中多种元素

用电感耦合等离子体质谱(ICP-MS)测定了地质样品中多种元素。考察了测量过程中的基体效应及质谱干扰,利用In内标,补偿由于基体效应的影响所引起的测量偏差,建立校正公式校正质谱干扰。方法的检出限为0.06~250ng/L,精密度为1.7%~3.2%,加标回收率为91%~108%,方法适于批量地质样品分析。     

微波等离子体炬-质谱法测定饮用水中微量钙

以微波等离子体炬(MPT)作为离子源,廉价离子阱为质量分析器,建立了用常见有机质谱仪测定饮用水中微量钙的方法.实验考察了MPT工作气流量、载气流量等参数对待测元素信号的影响,并对这些参数进行了优化.在优化的实验条件下,采用标准加入法对井水、自来水及瓶装饮用矿泉水等样品中的微量钙进行了测定.结果表明,该方法的检出限(LOD)为3.88 ng/L,相对标准偏差(RSD)为2.87%~8.04%,加标回收率(R)为101.3%~115.1%.     

微波等离子体炬质谱法快速测定大米中黄曲霉毒素B1的研究

以微波等离子体炬(MPT)为离子化源,在无需样品预处理的条件下,建立了快速测定大米中黄曲霉毒素B1(AFB1)的直接质谱分析方法。在正离子检测模式下,根据黄曲霉毒素B1的特征质谱离子(m/z 285)进行定量分析。结果表明,黄曲霉毒素B1在0.5~20μg/L范围内线性关系良好,相关系数(r2)为0.999 4,方法检出限为0.12μg/kg。直接检测复杂基体大米中的黄曲霉毒素B1,平均回收率为95.8%~107.2%,相对标准偏差(RSD,n=9)为2.2%~10.1%;将该方法与主成分分析(PCA)相结合,能够准确地鉴别大米是否霉变。该方法分析速度快、灵敏度高,适合霉变大米的快速、高通量筛查,有望应用于粮油食品、动植物食品质量监控等领域。     

超高效液相色谱-三重四极杆质谱联用仪同时检测水中9种亚硝胺

采用超高效液相色谱-三重四极杆质谱联用仪(UPLC-MS/MS)优化了9种亚硝胺的质谱运行参数,并通过对比不同流动相、固相萃取柱和定容溶剂对水中9种亚硝胺检测强度的影响,确定以甲醇-10 mmol/L碳酸氢铵溶液为流动相,使用椰壳活性炭萃取柱对样品进行预处理,超纯水作为定容溶剂。在最优实验条件下,9种亚硝胺的线性范围为5~150 ng/L,相关系数(r2)为0.997~0.999,检出限和定量下限分别为1.3~2.8 ng/L和4.0~8.5 ng/L;日内(n=5)和日间(n=6)相对标准偏差分别为3.5%~8.4%和2.8%~7.5%。3种不同实际水样在25 ng/L和100 ng/L加标浓度水平下,回收率达80.4%~109.6%。使用该方法对6个不同给水处理厂和污水处理厂出水中的亚硝胺浓度进行检测,其中N-亚硝基二甲胺(NDMA)的检测浓度最高,分别为10.2 ng/L和45.6 ng/L。     

微波等离子炬质谱负模式检测水中常见过渡金属离子

研究了负离子模式下锰、铁、钴、镍、铜和锌等常见过渡金属的微波等离子体炬(MPT)质谱特征,阐明了这些金属元素在MPT中形成阴离子的规律;初步得出饮用水中这些金属元素的最低检出限(LOD)均在约20μg/L量级,为实际检测这些金属元素奠定了基础.     

微波消解电感耦合等离子体质谱法测定大气气溶胶中的铂元素

采用高压密闭微波消解系统消解样品,结合电感耦合等离子体质谱(ICP-MS)法,测定了上海市区大气气溶胶样品中Pt元素的含量。实验采用数学校正方法扣除HfO复合离子对Pt元素测定的干扰,用标准溶液模拟样和铂族元素标准物质检验方法的可靠性,其测定值与标准值相吻合。Pt、Hf的检出限分别为0.3 ng/L、3.0 ng/L;Pt和Hf的空白值分别为1.0±0.1 ng/L和29.0±1.0 ng/L。对采集的3个气溶胶样品的测定结果表明:上海市区大气气溶胶中Pt的平均含量为1.5±1.0 pg/m3,低于世界其他城市。     

电感耦合等离子体质谱法测定水中铀钍元素的含量

建立了电感耦合等离子体质谱测定水中铀钍元素含量的方法。水样以硝酸酸化处理后直接用电感耦合等离子体质谱法测定,为了消除铀记忆效应对测定结果的干扰,测试溶液的质量浓度以不超过10μg/L为宜,样品测定间隙设置清洗时间为2 min。铀钍元素标准曲线线性相关系数分别为0.999 4,0.999 5;铀、钍的检出限分别为0.000 9,0.002 1μg/L;加标回收率分别为95.70%~112.33%,96.94%~109.98%;测定结果的相对标准偏差分别为0.61%~5.33%,1.16%~1.33%。     

有机溶剂溶样-电感耦合等离子体质谱法直接测定六氟磷酸锂中26种杂质元素

建立了电感耦合等离子体质谱(ICP-MS)法直接测定六氟磷酸锂中26种杂质元素(Be,Na,Mg,Al,K,Ca,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn,Ga,Sr,Zr,Mo,Pd,Ag,Cd,Sn,Sb,Ba,Pb)的分析方法。样品用无水乙醇溶解后直接用ICP-MS测定。通过在等离子体中引入氧气,避免样品溶液中高浓度碳冷凝沉积在质谱锥接口和离子透镜上导致分析元素灵敏度的降低的现象,采用碰撞/反应池(CRC)技术校正了多原子离子质谱干扰,选择基体匹配法校正了基本效应。结果表明,26种杂质元素定量标准曲线的线性相关系数不小于0.9995,检出限在0.6~31.9 ng/L之间,RSD为2.5%~7.3%,加标回收率在90.6%~108.6%之间。本方法能满足六氟磷酸锂中杂质元素的分析要求。     

固相萃取–HPLC–ICP/MS法测定水中的烷基汞

建立了固相萃取、高效液相色谱与电感耦合等离子体质谱联用技术测定水中烷基汞的方法。对固相萃取、高效液相色谱和电感耦合等离子体质谱的实验条件进行了优化。在优化条件下,甲基汞和乙基汞的检出限分别为0.5,0.7 ng/L。对地表水、工业废水和生活污水3种水样分别加标10.0,50.0 ng/L进行测定,测定结果的相对标准偏差为3.3%~9.6%(n=6),加标回收率在81.0%~103.0%之间。该方法灵敏度高,实用性强。     

Detection of uranium in industrial and mines samples by microwave plasma torch mass spectrometry

Microwave plasma torch (MPT), traditionally used as the light source for atomic emission spectrophotometry, has been employed as the ambient ionization source for sensitive detection of uranium in various ground water samples with widely available ion trap mass spectrometer. In the full‐scan mass spectra obtained in the negative ion detection mode, uranium signal was featured by the uranyl nitrate complexes (e.g. [UO₂(NO₃)₃]^?), which yielded characteristic fragments in the tandem mass spectrometry experiments, allowing confident detection of trace uranium in water samples without sample pretreatment. Under the optimal experimental conditions, the calibration curves were linearly responded within the concentration levels ranged in 10–1000 µg·l^?1, with the limit of detection (LOD) of 31.03 ng·l^?1. The relative standard deviations (RSD) values were 2.1–5.8% for the given samples at 100 µg·l^?1. The newly established method has been applied to direct detection of uranium in practical mine water samples, providing reasonable recoveries 90.94–112.36% for all the samples tested. The analysis of a single sample was completed within 30 s, showing a promising potential of the method for sensitive detection of trace uranium with improved throughput. Copyright © 2016 John Wiley & Sons, Ltd.     

Microwave plasma torch mass spectrometry for the direct detection of copper and molybdenum ions in aqueous liquids

Microwave plasma torch (MPT) is a simple and low power‐consumption ambient ion source. And the MPT Mass spectra of many metal elements usually exhibit some novel features different from their inductively coupled plasma (ICP) mass spectra, which may be helpful for metal element analysis. Here, we presented the results about the MPT mass spectra of copper and molybdenum elements by a linear ion trap mass spectrometer (LTQ). The generated copper or molybdenum contained ions in plasma were characterized further in collision‐induced dissociated (CID) experiments. These researches built a novel, direct and sensitive method for the direct analysis of trace levels of copper and molybdenum in aqueous liquids. Quantitative results showed that the limit of detection (LOD) by using MS² procedure was estimated to be 0.265 µg/l (ppb) for copper and 0.497 µg/l for molybdenum. The linear dynamics ranges cover at least 2 orders of magnitude and the analysis of a single aqueous sample can be completed in 5–6 min with a reasonable semi‐quantitative sense. Two practical aqueous samples, milk and urine, were also analyzed qualitatively with reasonable recovery rates and RSD. These experimental data demonstrated that the MPT MS is able to turn into a promising and hopeful tool in field analysis of copper and molybdenum ions in water and some aqueous media, and can be applied in many fields, such as environmental controlling, hydrogeology, and water quality inspection. Moreover, MPT MS could also be used as the supplement of ICP‐MS for the rapid and in‐situ analysis of metal ions. Copyright © 2016 John Wiley & Sons, Ltd.     

微波等离子体炬发射光谱法测定镉的研究

本文提出了一种灵敏测定痕量镉的微波等离子体炬发射光谱法(MPTAES)。探讨了微波等离子体炬(MPT)光源的一些基本特性.采用电热蒸发微量进样装置进样,详细考察了各种实验参数对测定镉的影响.在228.8nm处测定镉,检出限为0.28ng/mL.实际样品的测定结果是令人满意的.     

Simultaneous determination of perfluoroalkyl phosphonates, carboxylates, and sulfonates in drinking water

A trace analytical method based on high performance liquid chromatography coupled to quadrupole time-of-flight high resolution mass spectrometry was developed for simultaneous determination of perfluoroalkyl phosphonates (PFPAs, carbon chain lengths C6,8,10), perfluoroalkyl carboxylates (PFCAs, C5-12), and perfluoroalkyl sulfonates (PFSAs, C4,6,8,10) in drinking water (tap water). Analytes were enriched on a mixed mode co-polymeric sorbent (C8+quaternary amine) using solid phase extraction. Chromatographic separation was achieved on a Zorbax Extend C18 reversed phase column using a mobile phase gradient consisting of water, methanol, and acetonitrile containing 2mM ammonium acetate and 5 mM 1-methyl piperidine. The mass spectrometer was operated in electrospray negative ion mode. Use of 1-methyl piperidine in the mobile phase resulted in a significant increase in instrument sensitivity for PFPAs through improved chromatographic resolution, background suppression, and increased ionization efficiency. Method detection limits for extraction of 500 mL tap water were in the ranges of 0.095-0.17 ng/L, 0.027-0.17 ng/L, and 0.014-0.052 ng/L for PFPAs, PFCAs, and PFSAs, respectively. Whole method recoveries at a spiking level of 0.5 ng/L to 500 mL HPLC grade water were 40-56%, 56-97%, and 55-77% for PFPAs, PFCAs, and PFSAs, respectively. A matrix effect (signal enhancement) was observed in the detection of PFPAs in tap water extracts, leading to calculated recoveries of 249-297% at a 0.5 ng/L spiking level. This effect resulted in an additional improvement of method sensitivity for PFPAs. To compensate for the matrix effect, PFPAs in tap water were quantified using matrix-matched and extracted calibration standards. The method was successfully applied to the analysis of drinking water collected from six European countries. PFPAs were not detected except for perfluorooctyl phosphonate (PFOPA) at close to the detection limit of 0.095 ng/L in two water samples from Amsterdam, the Netherlands. Highest levels were found for perfluorobutane sulfonate (PFBS, 18.8 ng/L) and perfluorooctanoate (PFOA, 8.6 ng/L) in samples from Amsterdam as well as for perfluorooctane sulfonate (PFOS, 8.8 ng/L) in tap water from Stockholm, Sweden.     

Direct desorption/ionization of analytes by microwave plasma torch for ambient mass spectrometric analysis

Ambient ionization is the new revolution in mass spectrometry (MS). A microwave plasma produced by a microwave plasma torch (MPT) at atmospheric pressure was directly used for ambient mass spectrometric analysis. H₃O⁺ and NH₄⁺ and their water clusters from the background are formed and create protonated molecules and ammoniated molecules of the analytes. In the full‐scan mass spectra, both the quasi‐molecular ions of the analytes and their characteristic ionic fragments are obtained and provide evidence of the analyte. The successful detection of active compounds in both medicine and garlic proves that MPT has the efficient desorption/ionization capability to analyze solid samples. The obtained decay curve of nicotine in exhaled breath indicates that MPT‐MS is a useful tool for monitoring gas samples in real time. These results showed that the MPT, with the advantages of stable plasma, minimal optimization, easy, solvent‐free operation, and no pretreatment, is another potential technique for ambient MS. Copyright © 2013 John Wiley & Sons, Ltd.     

电热蒸发进样低功率MPT—AES测定铜,锌,镉的研究

微波等离子体炬(MPT)是一种具有类似ICP炬管结构的新型等离子体光源,该光源的基本性质已进行了详细的研究。本文采用自制的低功率MPT为激发光源,以氧为工作气体,用微型电热蒸发装置进样,测得铜、锌和镉的检出限分别为3.3、1.4和1.7ng/mL。考察了碱金属元素对铜、锌和镉发射信号的影响,该方法应用于钢样中铜的测定,结果较好。     

调控微波等离子体能量进行药片活性分子结构的质谱分析

采用微波等离子体质谱(MPT-MS)技术,对替硝唑和马来酸氯苯那敏药片进行快速质谱分析.通过调控等离子体能量,在一级谱图中可得到目标物的准分子离子及丰富的碎片离子,这些碎片离子与其对应串联质谱数据基本一致,甚至更加丰富;结合标准品比对分析,最终确定这些碎片离子来自目标物而非基质.因此,MPT兼具硬电离和软电离性质,采用MPT-MS技术从一级质谱图中获得的数据可对药片中活性分子的结构进行鉴定.该方法具有快速、准确及环保等特点,在发展MPT与简单的质量分析器联用,实现质谱仪的小型化等方面有广阔的应用前景.     

Dual ambient plasma source ionization mass spectrometry for the rapid detection of trace sterols in urban water

A direct analytical method based on dual ambient plasma ion source tandem mass spectrometry was used for the simultaneous determination of four sterols in the environment. This technology has very high sensitivity and the method detects the four sterols in methanol–water (1:3) solutions with limits of detection (LOD) and limits of quantification (LOQ) ranging from 1.2 ng/L to 6.9 ng/L and 7.6 ng/L to 10.0 ng/L, respectively. The method was also used to test water quality at three locations within the city and successfully detected all four sterols at very low concentrations. The dual plasma source tandem mass spectrometry technique is extremely simple, rapid, sensitive and highly efficient compared to other traditional methods, providing a useful screening tool for sterols in water.     

Trace level analysis of polycyclic aromatic hydrocarbons in surface waters by solid phase extraction (SPE) and gas chromatography-ion trap mass spectrometry (GC-ITMS).

Ontario Provincial Water Quality Objectives for polycyclic aromatic hydrocarbons (PAHs) in surface waters require low parts per trillion (ng L(-1))/high parts per quadrillion (pg L(-1)) detection limits. To meet these monitoring requirements, a solid phase extraction-gas chromatography-ion trap mass spectrometry (SPE-GC-ITMS) method was developed. Seventeen priority PAHs commonly monitored in surface and drinking waters were examined using an external ionization ion trap mass spectrometer operated in selected ion monitoring (SIM) mode. Under 70 eV electron ionization (El) conditions, both the quantitative [M]+* ion and confirmatory [M - 2H]+* ion were formed in classical abundance ratios. Each of these ion species was isolated in the ion trap using a specific scan function. However, to overcome poor levels of confirmatory ion abundance which otherwise restrict PAH method detection limits (MDLs), the abundance of [M - 2H]+* ions was augmented during isolation by causing the dissociation of [M]+* with the broad-band waveform used for high mass ion ejection. Augmenting the [M - 2H]+* signal intensity facilitated the achievement of MDLs of approximately 1 ng L(-1). PAHs in surface water samples that were not detected by current Ontario Ministry of the Environment high-performance liquid chromatography (HPLC)-fluorescence and GC-single-stage quadrupole mass spectrometry methods were detected and quantified using the ion trap mass spectrometry SIM method. The data produced by all three methods on natural water samples fortified at sub-parts per billion (ppb) levels were comparable. When applied to Standards Council of Canada/Canadian Association for Environmental Analytical Laboratories (SCC/CAEAL, www.CAEAL.ca) accreditation audit samples, the SPE-GC-ITMS method results met all performance evaluation criteria.