改良QuEChERS法提取-气相色谱-火焰光度检测同时测定茶叶中5种有机磷农药残留

采用改良的QuEChERS法提取,气相色谱-火焰光度检测(GC-FPD),建立了同时测定茶叶中敌敌畏、乐果、毒死蜱、水胺硫磷和三唑磷5种有机磷农药(OPPs)残留的分析方法。茶叶样品经改良的QuEChERS方法进行前处理,经GC-FPD检测,基质外标法定量。在最优条件下,上述5种有机磷农药的线性范围分别为:1.8~100μg/L、2.0~200μg/L、0.5~100μg/L、1.6~200μ/L和1.2~200μg/L,相关系数r均大于0.998。在2~50μg/L添加水平范围内,5种目标农药的平均回收率在80%~108.3%之间,相对标准偏差(RSD,n=5)为2.58%~7.31%,检出限(S/N=3)在0.608~4.420μg/kg之间,定量限(S/N=10)在3.448~10.736μg/kg之间。该方法检出限低、操作简单、分析速度快,适用于茶叶中上述5种有机磷农药残留的同时检测。     

LC-MS/MS法同时测定4种中草药中155种农药残留

建立了液相色谱-串联质谱(LC-MS/MS)同时测定4种中草药(甘草、银杏叶、菊花和八角茴香)中155种农药残留方法。样品采用乙腈、无水硫酸镁和乙酸钠分散固相萃取(DSPE),再经Cleanert TPH固相萃取(SPE)柱净化,乙腈/甲苯(8:1,V/V)洗脱,液相色谱串联质谱多反应监测模式下测定,外标法定量。实验结果表明,155种农药的检出限(S/N=3)和定量限(S/N=10)范围分别为0.4～34.1μg/kg和1.3～113.7μg/kg;在1.0～2400.0μg/kg浓度范围内,155种农药中有148种农药在4种中草药中线性相关系数平均值R2≥0.9950;在低、中、高3个添加水平,86.5%～97.4%的农药平均回收率在60%～120%范围,94.2%～100.0%的农药相对标准偏差RSD≤20%(n=5)。该方法适用于中草药中农药多残留检测。     

固相萃取-气相色谱/质谱法测定人参种植土壤中48种农药残留

采用固相萃取方法,结合气相色谱-质谱(GC/MS)建立了同时检测人参种植土壤中48种农药残留的分析方法。研究了萃取剂、固相萃取柱、洗脱剂种类和用量对样品提取及净化效果的影响,并考察了共萃取基质和基质效应,质谱采用选择离子监测(SIM)模式,外标法定量。结果表明,48种农药在各自的线性范围内,线性关系良好(r~20.995);在3个添加水平(10、20、100μg/kg)的回收率为86.3%～128.8%,相对标准偏差(RSD,n=6)为1.5%～14.6%。48种农药的检出限为2.0～6.0μg/kg,定量限为5.0～20.0μg/kg。该方法样品前处理简单、高效,测定的准确性好、灵敏度高,适用于人参种植土壤中多种类农药残留的筛选与测定。     

QuEChERS/高效液相色谱-串联质谱法测定土壤中61种激素类药物残留

建立了QuEChERS/高效液相色谱-串联质谱(HPLC-MS/MS)测定土壤中61种激素类药物残留的分析方法。样品经乙腈提取,QuEChERS方法净化后进行HPLC-MS/MS测定。采用电喷雾离子源(ESI),正、负模式扫描,多反应监测(MRM)模式采集,基质匹配工作曲线法定量。结果表明:61种目标化合物在各自浓度范围内线性良好,相关系数(r~2)为0.991 8～0.999 8,检出限(LOD,S/N≥3)为0.01～2.3μg/kg,定量下限(LOQ,S/N≥10)为0.03～7.5μg/kg;在10、50、200μg/kg 3个加标水平下,平均回收率为62.6%～102%,相对标准偏差(n=6)为1.0%～11%。该方法简单、快速、重现性好、稳定性高,可满足土壤中61种激素类药物残留的检测要求。     

QuEChERS-气相色谱-串联质谱法测定葡萄干中的80种农药残留

建立了QuEChERS前处理,结合气相色谱-串联质谱(GC-MS/MS)法测定葡萄干中80种农药残留的分析方法。样品以1%的乙酸乙腈-NaAc提取,经乙二胺-N-丙基硅烷(PSA)和聚苯乙烯/二乙烯苯(PEP)吸附剂净化,采用气相色谱-串联质谱法,以多反应监测(MRM)模式进行检测,基质匹配外标法定量。结果表明,80种农药在各自线性范围内相关系数均大于0.991;以信噪比(S/N≥3)确定方法的检出限(LOD),其范围为0.2～6.2μg/kg;以S/N≥10确定方法的定量限(LOQ),其范围为0.6～20.5μg/kg。3个加标水平(20、50、100μg/kg)下,80种农药的回收率在62.5%～116.6%之间,相对标准偏差为3.3%～15.4%。该方法的准确度高,精密度好,通用性强。     

QuEChERS-高效液相色谱/串联质谱法同时测定茶油中21种农药残留

采用QuEChERS结合液相色谱/串联质谱法建立了茶油中21种农药残留的快速分析方法。样品用乙腈均质提取,PSA和C18净化。对色谱、质谱条件和样品前处理进行了优化。在多反应监测(MRM)模式下进行质谱分析,外标法定量。21种农药在5.0～200μg/L范围内具有良好的线性关系,相关系数均大于0.995。在50,100,200μg/kg水平的平均加标回收率为63.1%～128.6%,RSD为1.6%～15%。21种农药的定量限为0.12～6.93μg/kg。方法适用于茶油中21种农药的定量与定性分析。     

固相萃取/气相色谱法测定禽蛋中19种农药残留

建立了QuEChERS及固相萃取净化技术结合气相色谱法测定禽蛋中19种农药(联苯菊酯、甲氰菊酯、氯菊酯、氯氰菊酯、氰戊菊酯、溴氰菊酯、敌敌畏、甲胺磷、乙酰甲胺磷、二嗪磷、乐果、甲基嘧啶磷、毒死蜱、杀螟硫磷、丙溴磷、氟虫腈、氟甲腈、氟虫腈硫醚及氟虫腈砜)残留的分析方法。蛋液样品经乙腈及QuEChERS提取盐包提取后,采用石墨化碳黑(GCB)吸附剂和十八烷基硅烷键合硅胶(C_(18))SPE小柱净化,以Agilent DB-1701(30 m×0.32 mm,0.25μm)毛细管色谱柱分离,在气相色谱火焰光度检测器(Flame photometric detector,FPD)及电子捕获检测器(Electron capture detector,ECD)上检测,外标法定量。结果显示,19种农药在各自线性浓度范围内线性关系良好,相关系数(r~2)均不小于0.999 3;在低、中、高3个加标水平下的回收率为78.6%～105%,相对标准偏差(n=6)为1.6%～9.3%,检出限(LOD,S/N=3)为0.138～8.33μg/kg,定量下限(LOQ,S/N=10)为0.461～27.8μg/kg。该方法操作简便、分离效果好、可靠稳定,可满足禽蛋中多种农药残留的检测要求。     

气相色谱-三重四极杆串联质谱结合QuEChERS测定三七中有机磷农药残留

建立了改良的QuEChERS样品前处理法,结合气相色谱-三重四极杆串联质谱(GC-MS/MS)同时测定三七中18种有机磷农药残留的方法。样品经1%乙酸-乙腈提取,改良QuEChERS技术净化,利用GC-MS/MS采取多反应离子监测模式测定,基质匹配校准曲线外标法定量。18种有机磷农药残留在2.5~120.0μg/kg范围内线性良好,相关系数(R2)大于0.99;检出限为0.4~1.5μg/kg,定量限为0.8~2.5μg/kg。在3个加标水平(2.5,8.0,60.0μg/kg)下平均回收率为70.5%~118.9%,相对标准偏差为1.0%~9.8%。     

小麦中多种农药的快速残留分析

建立了同时测定小麦中12种农药(灭线磷、甲拌磷、甲基毒死蜱、八氯二丙醚、马拉硫磷、毒死蜱、氟虫腈、杀扑磷、溴虫腈、三唑磷、联苯菊酯和甲氰菊酯)残留的快速分析方法.样品采用改进的QuEChERS进行前处理,用1%乙酸乙腈提取,C18和中性氧化铝双重净化后,结合GC-MS/SIM对小麦中的12种农药进行检测.结果表明,小麦中12种农药的加标水平为0.025 ～1.0 mg/kg时,平均回收率为76% ～108%,相对标准偏差为0.4% ～10.5%;方法的定量下限(S/N=10)为0.5 ～9.8 μg/kg,低于欧盟设定的MRLs值.     

QuEChERS/超高效液相色谱-串联质谱法同时测定土壤中67种农药残留

建立了同时测定土壤中67种农药的QuEChERS/超高效液相色谱-串联质谱法(QuEChERS/UPLCMS/MS)方法。样品经乙腈振荡提取、QuEChERS净化,采用超高效液相色谱-串联质谱测定。质谱分析采用电喷雾电离,正负双离子扫描,多反应监测(MRM)模式。结果表明:67种农药在5~500μg/L范围内均呈良好的线性关系,相关系数为0.990~0.999,检出限为0.001~0.010 mg/L;在10、50、500μg/kg 3个加标水平下的平均回收率为58%~111%,相对标准偏差(n=5)为1.1%~19.3%;定量下限为10μg/kg。该方法简单、快速、重现性好、灵敏度高,可满足土壤中67种农药残留的检测要求。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。