Substoichiometric Isotope Dilution Analysis of Sulphur in coal

Abstract

Substoichiometric radioisotope dilution analysis has been applied to the determination of sulfur in coal. The experimental procedure involved the combustion of coal samples labelled with ³⁵S as sodium sulfate in a flowing oxýgen stream, collection of the combustion gases in hydrogen peroxide and substoíchiometric precipitation of barium sulfate. Samples of 0.2–10.0% sulfur were accurately determined with ±2% RSD by measuring the activity of the precipitates thus obtained and with comparison to standard samples carried through the same procedure. Analysis times of 15 minutes per sample were typical.     

高效液相色谱-同位素稀释质谱法测定血清中的苯丙氨酸

苯丙酮尿症(PKU)是一种世界性分布的遗传疾病,病人体内缺少苯丙氨酸羟化酶(PAH),导致苯丙氨酸(Phe)不能正常代谢为酪氨酸,引起Phe代谢产物在人体中过量蓄积,造成患者中枢神经系统受到不可逆的损害而影响智力.     

Determination of Neodymium and Ytterbium by Isotope Dilution Laser Mass Spectrometry

The experimental conditions for minimizing errors in the laser mass spectrometric (LMS) analysis of isotopic ratios for Nd and Yb were found, and the optimum isotope pairs for determining these elements with the use of isotope dilution (ID) were chosen. The precision and accuracy of LMS data, which are characterized by relative random errors (RSD) and relative systematic errors (), can be improved using ID. The values for Nd or Yb were no higher than RSD = 2.9% and = 0.024 or RSD = 5% and = 0.097, respectively.     

流动注射同位素稀释电感耦合等离子体质谱测定钐

提出了一种利用流动注射同位素稀释电感耦合等离子体质谱测定地质样品中钐的方法。在采样体积为300μL的条件下，该法灵敏度较连续雾化进样提高了近4倍，分析速度为60样／min，检出限为0．42μg/L。     

同位素稀释质谱法测定国际比对水样中的铅

使用热表面电离质谱，采用同位素稀释质谱法测定国际物质量咨询委员会组织的第三次国际比对研究样中的铜样品中的铅，浓缩的＾２０６Ｐｂ稀释剂分用两种不同浓度的天然丰度的Ｐｂ标准溶液标定。然后用它作稀释剂。测量ＣＣＱＭ比对样品扣 铅，测定结果是０．０５００７２±０．００００９１μｍｏｌ／ｇ，与其他国家提供的数据相比，被组织证实为最佳。     

同位素稀释-火花源质谱法分析人参样品中微量元素

本文采用同位素稀释-火花源质谱法定量分析了吉林野山参,园参及高丽参中30多种微量元素的含量。测定下限2μg/g,相对标准偏差在5～28％以内。     

同位素稀释质谱法测定三文鱼中的孔雀石绿

建立了三文鱼中孔雀石绿和无色孔雀石绿的同位素稀释质谱测定法,即:通过添加作为同位素稀释剂的氘代孔雀石绿和无色孔雀石绿到样品中,经液液萃取、提取液中添加中性氧化铝以及过碱性氧化铝小柱进行净化的前处理,然后由以乙腈和乙酸铵缓冲液(0.05mol/L,pH 4.5)为流动相的液相色谱/离子阱质谱联用来作为分离检测手段.对含不同浓度孔雀石绿和无色孔雀石绿的储备液在不同溶剂、酸度、时间和温度的稳定性、前处理过程中的中性氧化铝的合适添加量、破乳剂的选择、孔雀石绿和无色孔雀石绿在氮吹和旋蒸过程中的损失以及液相色谱和质谱条件进行了研究.该方法的孔雀石绿和无色孔雀石绿的叫收率分别为95.6%～103.3%和97.64%～100.80%,检测限为0.4和0.3,μg/kg,相对标准偏差分别为4.76%～6.13%和3.14%～5.67%.结果表明,所建立的方法快速、灵敏、准确、可靠.     

碰撞池-同位素稀释质谱法测定塑料样品中铬含量

1 引言 人体若摄入极限量的铬酸或铬酸盐后,会引起肾脏、肝脏、神经系统和血液的广泛病变.欧盟RoHS指令(2002/95/EC)和我国的<电子信息产品污染控制管理办法>相继实施,对在市场出售的电子电气设备中Pb、Hg、Cd、Cr重金属及多溴联苯(PBB)和多溴联苯醚(PBDE)的含量进行了限制.由于样品中铬的含量较低、在样品预处理过程中易损失等原因,使得准确测量复杂基体中的铬存在困难.同位素稀释质谱法(IDMS)是在试样处理前加入待测元素的富集同位素,利用所加稀释剂的量和同位素丰度比值的变化的测定来计算待测样品中元素浓度的方法.     

同位素稀释高效液相色谱-串联质谱法测定水果及其制品中的展青霉素

建立了同位素稀释高效液相色谱-串联质谱法对水果及其制品中的展青霉素进行测定。澄清果汁(浊汁、固液体及固体样品需用果胶酶酶解处理,乙酸乙酯提取浓缩后复溶)经混合型阴离子交换柱净化、富集后,采用Waters HSS T3柱(2.1 mm×100 mm,1.8μm)以乙腈-水为流动相梯度洗脱,电喷雾离子源离子化,负离子多反应离子监测(MRM)模式检测,同位素稀释内标法定量。展青霉素在5~250 ng/m L浓度范围内线性关系良好,相关系数(r~2)大于0.999,该方法在不同基质不同加标浓度下,回收率为90.6%~110.1%,相对标准偏差(RSD)为1.4%~3.9%,定量下限为5.0μg/kg(苹果汁中定量下限为2.0μg/kg)。该方法准确可靠、灵敏度高,适合于水果及其制品中展青霉素的测定,可满足我国GB 2761-2011对于水果制品、果蔬汁和酒类(仅限苹果和山楂)中展青霉素残留的检测要求。     

同位素稀释超高效液相色谱-串联质谱法测定人血清中孕酮

建立了超高效液相色谱-串联质谱(UPLC-MS/MS)测定人血清中孕酮的分析方法。血清样品经乙酸乙酯、正己烷液液萃取(LLE)后,采用Acquity UPLC BEH C₁₈色谱柱(2.1 mm×100 mm,1.7μm)进行梯度分离,色谱运行时间为5 min,采用电喷雾(ESI)正离子电离模式和多反应监测(MRM)扫描模式,同位素内标法定量。考察了两步萃取法对孕酮的提取效果,不同流动相的分离效果以及样品稳定性,结果表明以甲醇-0.1%氨水溶液为流动相时分离效果较好。优化条件下,孕酮在10～10 000pg/mL范围内线性关系良好(r²=0.999 8),方法检出限和定量下限分别为5、10 pg/mL;平均加标回收率为91.5%～106%,日内相对标准偏差(RSD)为1.2%～8.2%,日间RSD为4.1%～9.1%。采用该方法对30个真实血清样品进行测定,孕酮质量浓度为0.050 2～1.363 5 ng/mL,均在正常生理范围内。该方法灵敏度高、准确可靠,可用于临床血清样品中孕酮生理水平的检测。     

液相色谱同位素稀释质谱联用法测定纺织品中的痕量五氯苯酚

针对挪威PoHS指令、1999/51/EC以及REACH危险物质列表中对五氯苯酚的限量要求,建立了纺织品中痕量五氯苯酚残留量的液相色谱同位素稀释质谱联用法(LC-IDMS)。以酸化正己烷提取纺织品试样中的残留五氯苯酚,在Eclipse Plus C18柱(100mm×2.1mm I.D.,3.5μm)上,采用5mmol/L醋酸铵溶液/甲醇(体积比20∶80)为流动相进行分离,结合电喷雾电离离子化技术,在负离子模式下测定,进行质谱定量分析,以13C-五氯苯酚为内标进行定量。方法的定量限为0.005μg/g,在0.1～0.5μg/g个添加水平范围内的平均回收率为95%～105%,测定精密度为0.805%～1.40%。方法准确、可靠,适用于纺织品中痕量五氯苯酚残留的测定。同位素稀释质谱法作为一个基准方法,对五氯苯酚残留进行检测的计量学方法可靠性验证。     

同位素稀释-液相色谱-电感耦合等离子质谱(ICP-MS)法测定大米中的甲基汞

目前国标方法GB 5009.17—2021测量样品中甲基汞(含量≤0.1 mg/kg)的精密度为20%、定量限为0.02 mg/kg,对于定量限以下的样品检测存在困难;为了能精确地测量国家食品安全检测领域关注的甲基汞污染物,通过在样品中加入同位素稀释剂后以GB 5009.17—2021国标方法进行样品前处理,以液相色谱分离出汞形态,用ICP-MS检测同位素比值,考虑质量歧视效应后以同位素稀释质谱法定量,建立了同位素稀释-液相色谱-电感耦合等离子质谱法测定大米样品中甲基汞含量的方法。当样品中甲基汞含量在0.01~0.03 mg/kg时,方法的精密度为0.3%~22.8%,不确定度U为0.002~0.004 mg/kg,k=2。以鱼肉中总汞与甲基汞成分分析标准物质(GBW10029)作为质控样,测定得到三种大米样品中甲基汞含量(以Hg计)分别为(8±2)、(24±3)、(19±4) ng/g,经过不确定度评估后表明方法的准确度较高;质控样(GBW10029)甲基汞的证书值(以Hg计)为 (0.84±0.03) mg/kg,而测量结果为(0.83±0.08) mg/kg,对质控样的测量结果说明该方法可靠;同位素稀释法将浓度的测量转换成同位素的丰度比的测量,可避免前处理过程带来的误差,同位素稀释与质谱结合可用于大米中甲基汞的高精度分析。     

同位素稀释电感耦合等离子体质谱法分析降尘中铂族元素

选取(195)Pt和(108)Pd为待测同位素,(196)pt和(105)Pd为富集同位素,同位素稀释电感耦合等离子质谱法(ID-ICP-MS)测定降尘样品中(195)Pt/(196)Pt和(108)Pd/(105)Pd比值,分析样品中Pt和Pd含量.利用Dowex AG50W-8阳离子交换和N-苯甲酰-N苯基羟胺(B...     

土壤及蔬菜中微量汞的同位素稀释电感耦合等离子体质谱测定

建立了微波消解电感耦合等离子体质谱同位素稀释(ID/ICP-MS)测定微量汞的方法。考察了仪器参数及测量条件对汞同位素比值RHg(202Hg/200Hg)测量的影响,根据同位素比值测量误差的传递因子优化了富集同位素稀释剂(202Hg98%)的加入量,并以铊同位素比值(205Tl/203Tl)作为RHg(202Hg/200Hg)测量时发生质量歧视效应的校正因子;通过反同位素稀释法标定了富集汞同位素稀释剂的浓度。利用所建立的ID/ICP-MS方法测定了杨树叶(GBW07604)和湖积物(GBW07423)2种标准参考物中汞的含量,回收率分别为112%和100%。该方法具有准确度高、精密度好等优点,且样品前处理简便,适用于土壤及蔬菜等样品中微量及痕量汞的准确测定。     

同位素稀释高效液相色谱-串联质谱法测定面粉及面制品中的联二脲

建立了面粉及其制品中联二脲的同位素稀释高效液相色谱-串联质谱检测方法。采用纯水超声提取,含油脂的样品加正己烷脱脂,所得样液进行高效液相色谱-串联质谱测定。以乙腈与纯水为流动相,梯度洗脱,经Waters XBridge BEH Amide(3.5μm,4.6 mm×150 mm)色谱柱分离,MS/MS采用电喷雾电离正离子(ESI+),多反应监测(MRM)模式检测,同位素内标法定量。方法的线性范围为0.2~100μg/L,相关系数为0.999 9;在面粉、馒头、面包、油条和面条5种基质中的平均加标回收率为82.0%~113.6%,相对标准偏差(RSD)为2.1%~9.3%;方法定量下限(LOQ)为20μg/kg。应用该方法对136份市售的面粉及面制品进行检测,在42份样品中检出联二脲,检出率为30.88%。其中面粉检出4份,含量为43.7~564μg/kg;馒头未检出;面条检出2份,分别为70.8μg/kg与9 840μg/kg;油条检出1份,含量为2 480μg/kg;面包表层检出15份,含量为27.4~8 730μg/kg;面包内芯检出20份,含量为64.3~18 100μg/kg。该方法操作简单、灵敏快速、准确可靠,适用于面粉及其制品中联二脲的测定。     

Determination of Halide Traces in Environmental Samples by Mass Spectrometric Isotope Dilution Analysis

Abstract

Since 1985, the Goulden large-sample extractor (GLSE) has been used to isolate a broad array of trace-organic contaminants from large volumes of water. In this study, field-applied quality control measures, including matrix and surrogate spikes and blanks, were used to monitor method performance from GLSE extraction through GC-MS analysis. The method was applied to the determination of multiple classes of pesticides isolated from 4- to 112-L filtered surface-water samples. Average recoveries of six surrogate compounds ranged from 84 ± 18% for [²H₁₀]diazinon to 15 ± 13% for 4,4′-[²H₈]DDT, the low recoveries for which were largely a result of unmonitored breakdown of this surrogate by the GC injection system. Field-matrix-spike samples were prepared by fortifying 10-L, 35-L, and 110-L filtered surface-water samples with 68 pesticides to amended concentrations of 11-to 50-ng/L each. Recoveries ranged from not detected to greater than 100%. Variability in pesticide recoveries from triplicate 10-L water samples collected at one site averaged 5.7% relative standard deviation and did not exceed 19%.     

Stable Isotope Dilution Analysis of Gibberellin Residues in Tomato Paste by Liquid Chromatography-Tandem Mass Spectrometry

An accurate and sensitive method for the simultaneous determination of gibberellic acid(GA₃), gibberellin A₄(GA₄) and gibberellin A₇(GA₇) residues in tomato paste was developed by coupling solid phase extraction to high performance liquid chromatography-tandem mass spectrometry(LC-MS/MS) with electrospray ionization based stable isotope dilution analysis(SIDA). The isotope labeled internal standard can compensate for the losses during the extraction and cleanup steps and for discrimination due to ion suppression. After extraction from methanol, hydrophile lipophilic balance(HLB) solid phase extraction(SPE) column was tested for the capacity of the cleanup of the tomato paste in compared with C₁₈ SPE column which is the common way to the detection of GAs, and the former gained better result. Spiked experiments were performed in the non-contaminated tomato pastes and the recoveries of GA₃, GA₄ and GA₇ were 42.6%―75.0% in external standard method(ESM) and 91.1%―103.8% in internal standard method(ISM) respectively. The validities of this method were investigated and good analytical performance for the three GAs was obtained, including low limits of method detection(2 ng/g for GA₃ and GA₄, 0.3 ng/g for GA₇), excellent linear dynamic ranges(5―500 ng/g for GA₃ and GA₄, 1―100 ng/g for GA₇) and good relative standard deviation ranges(4.8%―9.4% for the intra-day test and 3.5%―11.9% for the inter-day test).     

同位素稀释气相色谱-三重四极杆质谱测定虾仁中氯霉素

建立了一种稳定同位素稀释技术测定虾仁中氯霉素的气相色谱-三重四极杆质谱分析方法。样品中氯霉素用乙酸乙酯提取,以N,O-双三甲基硅基三氟乙酰胺(BSTFA)+三甲基氯硅烷(TMCS)为衍生剂,用氘代氯霉素(D5-CAP)为内标物,采用反吹技术,用气相色谱-三重四极杆质谱中多反应监测模式(MRM)进行定性定量分析。该方法在0.5~25ng范围内线性良好,相关系数r=0.9991,低、高二种浓度加标回收率均在89.2%~106.4%之间,方法检出限为0.1μg/kg。