吹扫捕集-气相色谱/质谱法测定水中的乙醛、丙烯醛、丙烯腈和吡啶

水中的乙醛、丙烯醛、丙烯腈和吡啶经吹扫捕集、解吸后,用HP-VOC毛细管色谱柱进行GC分离,用GC-MS法选择离子模式(SIM)下进行检测,外标法定量。结果表明,选择取样量25 m L,吹扫流量为40 m L/min,吹扫温度为40℃,吹扫时间为15 min,解吸时间为2 min,解吸温度为200℃,烘焙时间20 min,乙醛和吡啶质量浓度在0.025~0.60 mg/L之间,丙烯醛和丙烯腈质量浓度在0.002 5~0.10 mg/L之间时,校准曲线呈线性关系,相关系数r0.995,乙醛、丙烯醛、丙烯腈和吡啶的方法检出限分别为0.001 6,0.001 3,0.000 5和0.002 1 mg/L。对3个不同浓度样品进行空白加标实验,测量的回收率为87.8%~114.3%,相对标准偏差(n=6)为2.51%~10.4%。对3批实际水样进行分析,其中一个废水水样加标回收率为79.2%~103.8%,相对标准偏差(n=6)为3.04%~6.39%。     

微波消解-石墨炉原子吸收法测定土壤中铊

通过研究土壤消解体系、混合基体改进剂的使用、石墨管类型的选择和标准加入定量过程对测定结果的影响,建立了适用于土壤中重金属铊的微波消解-平台石墨炉原子吸收方法。结果表明,使用HNO_3-HF-H_2O_2消解体系对土壤进行微波消解,石墨炉原子吸收测定过程采用Pd(NO_3)_2/Mg(NO_3)_2混合基体改进剂和平台石墨管,土壤中铊的检出限可达0.05 mg/kg,线性相关系数为0.996,加标回收率在95.0%~105.0%。使用该方法测得的结果与ICP-MS法比较,无统计学差异。改进后的方法具有简单快捷、灵敏度高、重现性好、线性范围广、结果准确等优势,易于推广使用。     

便携式气相色谱—质谱联用仪应急现场测定空气中54种VOCs

采用Inficon公司的HAPSITE四级杆气质联用仪,建立便携式气相色谱—质谱联用仪应急现场测定空气中54种挥发性有机物。对各种化合物的线性、加标回收率(56.3%~141.1%)、精密度(3.80%~22.69%)、检出限进行了测定,并将该方法运用到实际样品测定中。结果表明,该方法准确可靠、灵敏度好、分析速度快、操作简便,适用于空气中54种挥发性有机物的现场测定。     

固体吸附-热脱附/气相色谱-质谱法测定固定污染源废气中50种挥发性有机物

采用Tenax GR吸附-热脱附-气质联用法对固定污染源废气中50种挥发性有机物(VOCs)进行测定。结果显示,Tanax GR吸附管对于丙酮、环戊酮、2-庚酮、2-壬酮及六甲基二硅氧烷的吸附能力相对较差,但丙酮、环戊酮、2-庚酮、2-壬酮在2~30 ng范围内呈现良好的线性关系,且相关系数(R 2)>0.99,六甲基二硅氧烷在2~50 ng范围内呈现良好的线性关系,R^2=0.994,其他45种化合物在2~100 ng范围内呈现良好的线性关系,R^2>0.995。当采样体积为300 mL时,50种化合物的检出限为0.0003~0.0096 mg/m^3,测定下限为0.0011~0.0384 mg/m^3,相对标准偏差(RSD)<15.98%,加标回收率为78.15%~120.90%。该方法操作简单、灵敏度高、准确性好,能够满足固定污染源废气中痕量VOCs的快速检测。     

鱼类样品中有机磷阻燃剂分析方法的优化研究

建立了鱼类组织样品中有机磷阻燃剂（OPFRs）的分析方法,优化了萃取条件、净化条件、液相色谱条件和质谱检测参数。确定了生物样品经冷冻干燥后,以1∶1（V/V）的正己烷/二氯甲烷混合溶液进行加速溶剂萃取,利用氨基固相萃取柱进行净化,以1∶1（V/V）的正己烷/二氯甲烷、二氯甲烷和9∶1（V/V）的二氯甲烷/甲醇为洗脱液,最后用超高效液相色谱-串联质谱同时对9种OPFRs进行定性定量检测。结果表明,各物质的基质加标回收率均为56.5%~108%,方法的测定下限为0.016~0.104 ng/g （以脂重计）,满足了生物样品中OPFRs的分析检测要求。利用该方法测定了北京和广州市养殖和野生鲫鱼肌肉组织样品,主要的OPFRs同族体为磷酸三正丁酯（TNBP）、磷酸三乙基己基酯（TEHP）、磷酸三（1-氯-2-丙基）酯（TCIPP）和磷酸三氯乙基酯（TCEP）,质量比为5.94~33.7 ng/g（以脂重计）,显示出良好的适用性。     

自动石墨消解-石墨炉原子吸收法测定土壤中铅和镉

本文建立了一种自动石墨消解仪消解土壤样品,石墨炉原子吸收法测定土壤中的铅、镉的方法。铅、镉元素在标准曲线范围内线性良好,相关系数均大于0.999,检测限分别为0.02、0.007 mg/kg,加标回收率在90.8%~104.0%,方法重复性RSD(n=7)低于3%。实验结果表明,该方法操作简单、准确度高、精密度好、检测限低,可用于大批量土壤中铅、镉的测定。     

电感耦合等离子体原子发射光谱法测定食品中的铝

采用硝酸-高氯酸消解,电感耦合等离子体原子发射光谱法(ICP-AES法)测定食品中铝。结果表明,消解液可以直接用水定容上机;在A l浓度0~6mg/L范围内,相关系数R2=0.9996,优于国标比色法(0~3μg范围内,R2=0.981);该方法检出限为0.15mg/kg,极大地优于国标比色法(12.5 mg/kg);同一样品比较,本法RSD为5.8%,而国标比色法只能达10%;该法回收率在92%~97%之间,对GBW 10016茶叶标准物质测定值也在可接受范围内。     

Assessment of GC–MS response of selected pesticides in apple matrices related to matrix concentration

A uniform analyte response is required for GC–MS analysis in order to obtain acceptable quantitative results. The response of pesticides in complex matrices is susceptible to variation due to the interactions of co-extractives, both with pesticides or with GC–MS system. This study was conducted to determine the magnitude of the interactions, called matrix effect, and their behavior with the matrix dilution. The response of pyrimethanil (4,6-dimethyl-N-phenylpyrimidin-2-amine), cyprodinil (4-cyclopropyl-6-methyl-N-phenylpyrimidin-2-amine), trifloxystrobin (methyl-(2Z)-2-methoxyimino-2-[2-[[(E)-1-[3(trifluoromethyl)phenyl]ethylidene amino]oxymethyl]phenyl]acetate) and bifenthrin(2-methyl-3-phenylphenyl)methyl-3-[(Z)-2-chloro-3,3,3-trifluoroprop-1-enyl]-2,2-dimethylcyclopropane-1-carboxylate), used in apple crops protection, was evaluated in different concentrations of peel and flesh extracts of Granny Smith, Golden Delicious and Demi Rouge, selected as representatives of different matrix types. The matrix effect ranged from ?0.05 to 146.14%, depending on matrix type and pesticide. The highest response variation was observed in extracts of Granny Smith—an enhancement in flesh and suppression in peel extract. With the dilution, the matrix effect decreased with different magnitudes, but for Granny Smith peel extract an inverted effect was observed. The presence of the matrix effect in GC–MS pesticides analysis was obvious, requiring the application of matrix-matched calibration in quantification procedures for each variety, with calibration standards matched by the matrix concentration.     

Simultaneous determination of pesticides,mycotoxins, tropane alkaloids,growth regulators,and pyrrolizidine alkaloids in oats and whole wheat grains after online clean-up via two-dimensional liquid chromatography tandem mass spectrometry

In this study, a two-dimensional liquid chromatography tandem mass spectrometry method was developed and validated for the determination of pesticide residues and contaminants in whole wheat grains and oats. The samples were extracted with a mixture of acetonitrile and water and were injected into the two-dimensional LC-MS/MS system without any further clean-up or sample preparation. Samples were analyzed with four different matrix matched calibrations. Matrix effects were evaluated by comparing analyte signals in the respective matrix matched standard with the neat solvent standards. The final method was validated according to the current Eurachem validation guide and SANTE document. The number of successfully validated analytes throughout all three validation levels in oats and wheat, respectively, were as follows: 330 and 316 out of 370 pesticides, 6 and 13 out of 18 pyrrolizidine alkaloids and 7 out of 9 regulated mycotoxins. Moreover, both plant growth regulators mepiquat and chlormequat as well as the tropane alkaloids atropine and scopolamine met the validation criteria. The majority of pesticides showed limits of detection below 1?µg kg^?1, pyrrolizidine alkaloids below 0.7?µg kg^?1, tropane alkaloids below 0.2?µg kg^?1, growth regulators below 0.7?µg kg^?1 and mycotoxins below 8?µg kg^?1 in both matrices.     

进口含锌物料的表征和鉴别

采用X射线荧光光谱(XRF)、X射线衍射光谱(XRD)等分析手段,对4种进口疑似固体废物的含锌物料进行了表征。通过分析含锌物料的主要元素组成、物相组成和常规理化特征,结合外观特征,与含锌矿物、含锌产品及相关文献资料等进行比对,推导出含锌物料的产生来源。然后,参照我国《进口废物管理目录》得出鉴别结论。结果表明:4种含锌物料分别为锌矿、湿法冶炼锌浸出渣、热镀锌灰和固定CO2产物;后3种属于我国目前禁止进口的固体废物。