固相萃取-液相色谱-串联质谱法测定水果和土壤中四螨嗪残留量

建立了水果和土壤样品中四螨嗪的液相色谱-电喷雾串联质谱检测方法。水果或土壤样品用丙酮提取,经弗罗里硅土柱净化,以Agilent ZORBAX SB-C18色谱柱分离,以电喷雾电离串联质谱正离子多反应监测模式进行测定。对四螨嗪在水果和土壤中在4个不同添加水平下的回收率进行了测定,结果表明,四螨嗪在柑橘(全果)中的添加回收率为86.9%～93.1%(RSD为7.4%～9.4%),在苹果中的添加回收率为84.1%～95.1%(RSD为5.9%～9.7%),在葡萄中的添加回收率为88.8%～93.7%(RSD为8.0%～10.1%),在梨中的添加回收率为88.6%～96.1%(RSD为7.0%～10.2%),在土壤中的添加回收率为83.0%～96.8%(RSD 6.7%～12%)。该方法满足农药残留检测要求,适用于水果和土壤中四螨嗪残留的检测。     

硅青铜光谱标准样品研制

经化学成分设计、原料精选、熔炼加工、均匀性检验等步骤,研制了硅青铜光谱标准样品。该硅青铜光谱标准样品以高纯铜为主原料,按杂质元素的性质,在选定的条件下分批加入Si、Ni、Zn等15种杂质元素制备而成。杂质元素的定值区间分别为:Zn 0.112%～4.29%,Pb 0.030%～0.264%,Sn 0.055%～0.611%,P 0.009 7%～0.107%,Mn0.066%～1.68%,Fe0.023%～2.02%,Ni0.116%～4.02%,Si0.147%～3.80%,Mg0.000 51%～0.007 2%,Cr0.009 8%～0.090%,As 0.001 4%～0.011%,Sb 0.001 6%～0.008 2%,Bi 0.000 74%～0.025%,Co 0.005 1%～0.051%,Al0.002 8%～0.082%。定值结果的扩展不确定度为0.000 04%～0.09%(k=2)。该标准样品成分设计合理,化学成分均匀,定值结果准确,涵盖范围广,可广泛用于硅青铜QSi0.6-2、QSi3-1、QSi1-3、QSi3.5-3-1.5等系列主、杂元素的分析检测,已被批准为国家级标准样品,标准编号为GSB 04-3755-2020。     

高效液相色谱法同时测定厚朴温中胶囊中的7种有效成分

建立了同时测定厚朴温中胶囊中山姜素、甘草酸、和厚朴酚、小豆蔻明、木香烃内酯、去氢木香内酯及厚朴酚含量的反相高效液相色谱法。固定相为Scienhome C18柱(250 mm×4.6 mm,5 μm),流动相为甲醇-乙腈-0.06%磷酸溶液(体积比为38∶27∶35),流速为1.0 mL/min,柱温为30 ℃,检测波长为235 nm。在上述条件下,山姜素、甘草酸、和厚朴酚、小豆蔻明、木香烃内酯、去氢木香内酯及厚朴酚的质量浓度分别在0.885～17.7,107～2140,8.85～17.7,1.035～20.7,4.85～97,5.9～118和17.5～350 mg/L时与色谱峰面积之间的线性关系良好;回收率分别为96.9%～101.1%,96.0%～100.5%,100.3%～100.8%,97.7%～101.4%,100.4%～102.3%,96.0%～102.3%和96.2%～100.6%。该方法简便、快速、准确,可用于厚朴温中胶囊的质量控制。     

液相色谱-串联质谱法测定蔬菜和水果中硝苯菌酯的残留量

建立了一种通过检测硝苯菌酯(2,4-dinitro-6-(1-methylheptyl) phenyl crotonate, 2,4-DNOPC)相应的水解产物2,4-二硝基-6-(1-甲基庚基)苯酚(2,4-dinitro-6-(1-methylheptyl) phenol, 2,4-DNOP)来测定蔬菜和水果中2,4-DNOPC残留量的液相色谱-电喷雾串联质谱(LC-ESI-MS/MS)检测方法。蔬菜和水果样品用丙酮-甲醇-盐酸的混合液进行液-液分配提取,在碱性条件下超声水解后再进行液-液分配提取,然后进行LC-MS/MS测定。2,4-DNOPC在6种蔬菜和水果中的回收率试验结果表明,2,4-DNOPC在甘蓝中的添加回收率为89.7%～93.3%,相对标准偏差(RSD)为6.3%～8.5%;在黄瓜中的添加回收率为87.7%～95.1%, RSD为5.8%～10.4%;在番茄中的添加回收率为89.3%～96.0%, RSD为6.8%～9.2%;在苹果中的添加回收率为92.0%～98.3%, RSD为5.1%～10.3%;在梨中的添加回收率为89.0%～95.0%, RSD为5.3%～10.2%;在葡萄中的添加回收率为81.2%～95.8%, RSD为5.8%～10.4%。2,4-DNOPC在6种蔬菜和水果的最低检测浓度均为0.01 mg/kg。该检测方法样品前处理简单、快速,分析时间短,灵敏度、准确度和精密度均符合农药残留检测要求,适用于蔬菜和水果中硝苯菌酯残留量的检测。     

环境中除草剂扑草净残留分析方法的研究

建立了高效液相色谱(HPLC)法测定环境中土壤、水和小麦中除草剂扑草净残留量的分析方法。采用丙酮超声提取,硅胶柱层析净化,测定土壤中扑草净残留量;水样直接用LC-18固相萃取小柱分离、净化和富集;采用超声提取,甲醇∶水=1∶1(V/V)为提取剂,LC-18固相萃取小柱分离、净化,测定小麦样品中扑草净的残留。结果表明:HPLC法检测扑草净的线性范围为0.5～16 mg.L-1,相关系数R2=0.9999,方法的检出限为0.0125 mg.L-1。土壤的加标回收率为88.2%～102.4%,相对标准偏差为6.3%～6.4%;水样的加标回收率为81.7%～102.5%,相对标准偏差为4.5%～4.6%;小麦的加标回收率为88.4%～101.7%,相对标准偏差为3.6%～5.5%。     

硅青铜和铝青铜光谱分析标准物质的研制

研制了2种硅青铜和10种铝青铜光谱分析标准物质。该标准物质以高纯铜为主料、按杂质元素的性质分批分期加入Cu-Fe、Ni、Si、Pb、Sn、Cu-As、Cu-S、Zn、Mn、Cr、Al、Cu-P等12种成分，采用250 kg中频感应炉冶炼，半连续铸造，2 000吨水压挤压机挤压而成，确保了标准物质的均匀性。8家权威实验室用准确可靠的分析方法确定了13种元素的标准值和不确定度。元素定值区间分别为：Cu 80.92%～95.77%,Pb 0.000 2%～0.001 5%,Zn 0.001 1%～0.034%,P0.000 4%～0.006 1%,Fe0.027%～4.09%,Sn0.001 2%～0.033%,As0.000 15%～0.000 4%,Al7.69%～10.26%,Mn0.055%～2.10%,Ni0.030%～4.48%,Si0.008 4%～3.31%,Cr0.012%～0.026%,S0.000 8%～0.000 9%。定值结果的扩展不确定度为0.000 04%～0.10%(k=2)。该标准物质的均匀性与稳定性良好，定值结果准确，已被国家市场监督管理总局批准为国家级标...     

惰性熔融-红外吸收/热导法测定高铍铍铝合金中氧氮

建立红外吸收/热导法同时测定高铍铍铝合金中氧氮的含量。称取0.03～0.04 g试样,以带盖镍囊(Φ7mm×6 mm)包裹,使用0.1 g纯铜助熔剂及0.05 g纯锡助熔剂为混合浴料,在4 500 W的分析功率下,高纯氦气氛中熔融释放气体,通过红外吸收池测定氧含量,热导池测定氮含量。对氧质量分数为0.217%～0.546%及氮质量分数为0.005 8%～0.012 0%的试样进行测定,测定结果的相对标准偏差分别为1.07%～3.00%(n=8)与4.55%～4.94%(n=8),氧的加标回收率为97.1%～103.8%,氮的加标回收率为95.9%～104.4%。该方法操作简单快捷,测定结果准确。     

柱前衍生-固相萃取/气相色谱法测定油菜、土壤中二氯吡啶酸

采用柱前衍生化法,建立了二氯吡啶酸在油菜植株、菜籽和土壤中的固相萃取-气相色谱测定方法.样品经NaOH溶液提取,乙酸乙酯萃取,甲醇浓硫酸衍生化后,Florsil固相萃取小柱净化,GC-ECD测定.空白油菜植株的平均添加回收率为82.8%～99.1%,RSD为1.0%～11%;菜籽的平均添加回收率为85.0%～94.9%,RSD为2.8%～8.5%;土壤的平均添加回收率为102.3%～109.7%,RSD为3.5%～9.8%.方法的检出限(LOD)为1.87μg/kg,定量限(LOQ)为4.0μg/kg.方法可完全满足农药残留分析要求.     

碘化钾―甲基异丁基甲酮萃取―火焰原子吸收法测定土壤中的痕量铅

土壤样品经微波消解,在优化的条件下,用碘化钾―甲基异丁基甲酮萃取,采用火焰原子吸收光谱法测定其中的铅。结果表明,在盐酸质量分数为1%～2%,萃取时间为2 min,平衡时间为15 min,样品中的铅能被定量萃取。方法检出限为0.1 mg/kg。方法用于土壤标准样品测定,测定值与标准值相符,相对标准偏差为1.2%～1.4%,相对误差为0.8%～2.5%。实际土壤样品的测定结果显示,回收率为99.8%～100.4%。     

半夏淀粉的理化特性

研究了不同产地的4种半夏淀粉的理化特性,包括直链淀粉含量、膨胀度、溶解性、持水性、淀粉粒大小和形貌、结晶类型、热特性和糊化特性等。结果表明,这些半夏淀粉中直链淀粉含量为18.60%～23.91%;膨胀度21.53%～23.09%;溶解度11.5%～32.3%;持水性100.3%～119.0%。淀粉粒单粒球形,卵形或圆半球形,直径2～20μm,复粒由2～3个分粒组成,其结晶类型均为C型,结晶度15.0%～37.9%。用差示扫描量热仪测得的转变温度TO、TP和TC分别为71.58～77.75℃、83.03～83.84℃和89.41～90.99℃,热焓为4.316～5.809 J/g。用快速粘度分析仪测定了4种半夏淀粉的糊化特征值:峰值粘度、热糊粘度、冷糊粘度、稀懈值和回复值分别为149.5～226.2、97.7～127.2、141.8～194.3、50.4～99.0和44.2～67.2 RVU。糊化温度77.8～79.9℃,峰值时间8.3～8.7 min。     

热脱附-气相色谱-三重四极杆串联质谱法测定环境空气中的挥发性有机物

采用热脱附(TD)结合气相色谱-三重四极杆串联质谱(GC-MS/MS)建立了环境空气中23种挥发性有机物(VOCs)同时检测的分析方法。空气样品通过主动采样的方式富集到装有Tenax-TA填料的热脱附管中,热解吸后在选择反应监测(SRM)模式下用GC-MS/MS进行检测,内标法定量。结果表明,23种VOCs在0.01~1 ng和1~100 ng低、高两个范围内线性关系良好,相关系数(r²)均大于0.99,方法定量限为0.00008~1 μ g/m³。加标水平为2、10和50 ng时,23种VOCs的平均回收率为77%~124%。除了最低加标水平的氯苯,相对标准偏差(RSD, n=6)均小于20%。对市内3个采样点的环境空气进行测定,其中苯、甲苯、乙苯、二甲苯、苯乙烯、1,2,4-三甲基苯和六氯丁二烯均有检出。实验证明,该TD和GC-MS/MS相结合的检测方法具有准确、可靠、灵敏度高等优点,适用于环境空气中VOCs的同时测定。     

微波消解石墨炉原子吸收法测定环境空气中痕量锡

建立石墨炉原子吸收法测定环境空气中痕量锡的方法。采用混合纤维素微孔滤膜采集环境空气样品,用硝酸–氢氟酸微波消解样品,以5%硝酸镧–10%酒石酸混合液作基体改进剂,石墨炉原子吸收法进行测定。当采样体积为4 800 L,定容体积50 m L时,方法检出限为0.024μg/m~3,样品加标回收率为96.0%~106.0%,测定结果的相对标准偏差为2.74%~5.81%(n=7)。该方法样品处理操作过程简单,酸用量少,可用于环境空气中痕量锡的测定。     

Determination of particle-associated hydroxynitropyrenes with correction for chemical degradation on a quartz fibre filter during high volume air sampling

A correction method for the determination of atmospheric monohydroxylated derivatives of 1-nitropyrene (hydroxy-1-nitropyrenes, OHNPs) based on their degradation rates during high volume air sampling was established. OHNPs adsorbed directly on a quartz fibre filter (QFF) or on airborne particles collected on a QFF were exposed to ambient air passively or actively in a high volume air sampling system. The influence of ozone flux and exposure time on the degree of degradation of OHNPs was investigated. Up to 50% of OHNPs degraded over 1 h of exposure to ambient air containing ～60 ppbv of ozone in the active system. The degradation rate constants of OHNPs were found to correlate with the number of ozone molecules passing through the QFF in a unit time (N_O3) during high volume air sampling. The chemical loss of OHNPs under high volume air sampling conditions was successfully evaluated by the exposure time and the pseudo-first-order rate constant for OHNP degradation estimated from the correlation with N_O3. Concentrations of 3-, 6-, and 8-hydroxy-1-nitropyrenes in airborne particles collected in Osaka, Japan were determined using the established correction method.     

Determination of passive-sampled sulphur dioxide in ambient air as sulphate ion by flow injection analysis with an in-line reaction column

A modified FIA method was developed for the determination of sulphur dioxide (SO(2)) in ambient air collected by a passive sampler. SO(2) was oxidized by hydrogen peroxide and determined as sulphate ion in solution. Barium-dimethylsulfoazo-III complex was used as spectrophotometric reagent. A BaSO(4)-immobilized in-line reaction column was introduced into the flow system to increase the sensitivity and reproducibility. An in-line cation exchange column was used to eliminate triethanolamine, which was used as the absorbent reagent in the passive sampler. Sulphate ions can be analyzed in the range of 0.08-10.00 mg l(-1) with the R.S.D. less than 1.6% at the rate of 15 samples h(-1). It was satisfactory to apply this method to the analysis of sulphur dioxide in ambient air and the results agreed with those obtained by ion chromatography.     

Development of an analytical technique and stability evaluation of 143 C3-C12 volatile organic compounds in Summa canisters by gas chromatography-mass spectrometry

A technique using Summa canisters with cryogenic preconcentration and gas chromatographic-mass spectrometric (GC-MS) detection was developed to determine 143 C3-C12 volatile organic compounds (VOCs) including alkanes, alkenes, aromatics and halohydrocarbons in ambient and indoor air. The method detection limits and practical quantification limits were sensitive at 0.02 and 0.10 ppbv, respectively, and the method precision and accuracy were also satisfactory. The stability of C3-C12 VOC standards at ppbv levels under elevated pressure in canisters was assessed over various time intervals (from 1 week to 4 months after preparation) and most of the compounds were found to be acceptably stable with a mean recovery of 85.6 +/- 9.9% during the course of a 4-month study. However, a small fraction (approximately 6%) of the compounds, including two halohydrocarbons (bromotrichloromethane and benzyl chloride) and six alkenes (2-methylbuta-1,3-diene (isoprene), cis-4-methylpent-2-ene, cis-3-methylpent-2-ene, hept-1-ene, oct-1-ene and styrene) displayed relatively low recoveries in the range 34.6-67.9%. The loss of these compounds is most probably caused by their physical adherence to the active sites of the canister surface, chemical decomposition and/or reactions with other species. The results indicated that one must be cautious in attempting to measure these compounds owing to their instability in canisters. Overall, this analytical technique, which has been used for the determination of the VOCs under study in the toxic air pollutant monitoring network administered by the HKSAR Government, was amenable to the measurement of airborne VOCs collected both outside and inside a semi-confined car park in the present study.     

加速溶剂萃取-高效液相色谱-串联质谱法测定空气中的全氟化合物

建立了加速溶剂萃取-高效液相色谱-串联质谱法(ASE-HPLC-MS/MS)测定环境空气样品中全氟化合物(PFCs)的分析方法。采用PS-1型大流量采样器采集环境空气样品,聚氨酯(PUF)收集空气,石英纤维滤膜(QFF)收集空气颗粒物。采用ASE萃取采样后的PUFs和QFFs,萃取剂为甲醇-丙酮(1∶1,V/V),萃取温度100℃,萃取压力15MPa,静态萃取时间15min,连续萃取3次。萃取液经K-D浓缩后转换溶剂为甲醇,采用HPLC-MS/MS测定PFCs的含量。线性范围在0.1～50μg/L之间,方法检出限在0.034～0.54pg/m3范围。应用本方法检测2007年5～6月在广州市采集的环境空气样品,蒸气态PFCs的总含量在5.2～37.4pg/m3范围内,颗粒态PFCs的总含量在11.3～74.3pg/m3范围内。本方法适用于监测环境空气中的痕量PFCs。     

Identification of alkyl dinitrates in ambient air of Central Europe

Bifunctional organic nitrates – organic esters of nitric acid – are part of the pool of components of odd nitrogen (NO_Y) in the atmosphere. In this paper, we report the identification of dinitrates in ambient air of Central Europe (Ulm, Germany). The organic nitrates were sampled by adsorptive high volume sampling of 100 m³ of air with 100 g precleaned silica. Sample preparation and group separation was performed by NP-HPLC. Separation and detection was done by HRGC/EI-MSD. We have extended the identification of dinitrates in ambient air to a number of 30, of which only five have been reported by other authors before. To our knowledge, this is the first time that 13 non-vicinal dinitrates and two branched dinitrates have been identified in ambient air. Four organic nitrates have never been reported before: the non-vicinal 1,3-dinitrooxy-pentane (1,3C5), the two branched 2-methyl-1,2-dinitrooxy-propane (2M1,2C3) and 2-methyl-2,3-dinitrooxy-butane (2M2,3C4), and one diastereomer of 3,4-dinitrooxy-hexane (RR/SS-3,4C6). We are also assigning the configuration of the two diastereomers of 2,4-dinitrooxy-pentane (2,4C5) found in air before using reference standards obtained by enantioselective synthesis. Received: 8 June 1998 / Revised: 7 September 1998 / Accepted: 14 September 1998     

Particle-particle chemistry between micrometer-sized PbSO4 and CaCO3 particles in turbulent flow initiated by liquid water

A mixture of natural and anthropogenic particles is ubiquitous in the troposphere and exerts an important influence on air quality. This work reports the study of mixing and heterogeneous chemistry of particles of natural-like mineral dust (CaCO(3)) and anthropogenic-like microparticle (PbSO(4)) in turbulent air flow under varying relative humidity. Sparse monolayers of laboratory-generated particles were collected on substrates using impaction. The grain size distribution and chemistry of micrometer-sized particles were determined as CaCO(3)-PbSO(4) internal and external mixtures by Raman imaging, scanning electron microscopy, and time-of-flight static secondary ionization mass spectrometry. The condensation of a thin water layer on mixed aggregates initiates the formation of complex internal mixtures of Pb(3)(CO(3))(2)(OH)(2), PbCO(3), CaSO(4)·2H(2)O, CaCO(3), and PbSO(4) fine particles. These heterogeneous chemistry processes which may occur in ambient air can increase dramatically the amounts of hazardous breathable particles.     

大流量采样-GC-NCI-MS测定环境空气中的多溴联苯醚

建立了大流量采样-气相色谱负化学电离质谱法测定环境空气中痕量多溴联苯醚的方法.用PS-1型大流量空气采样器采集环境空气样品,样品经提取、纯化后采用气相色谱负化学电离质谱法测定环境空气中多溴联苯醚.方法的线性范围在5～10000 pg/m3之间,检出限1～50 pg/m3.用于检测2006年5月在广州市采集的环境空气样品,多溴联苯醚组分含量在5.4～4989 pg/m3范围.该方法适合用于监测环境空气中的痕量PBDEs.     

Sampling and determination of gas phase divalent mercury in the air using a KCl coated denuder

KCl coated denuders were employed for the measurement of divalent mercury (Hg²⁺) species in the air. Laboratory tests show that gaseous Hg²⁺ can be collected by the denuder with an average efficiency of 98% and elemental Hg will pass through it freely. Hg²⁺ trapped in the denuder can be quantitatively extracted by 1 mol/L HCl and analyzed by the method of SnCl₂ reduction-CVAFS determination. Hg²⁺ concentrations of 0.04–0.15 ng m^–3 corresponding to about 2–9% of the total gaseous mercury in the ambient air were determined at several sampling locations.