免疫亲和柱净化-柱后光化学衍生-高效液相色谱法同时检测粮谷中的黄曲霉毒素、玉米赤霉烯酮和赭曲霉毒素A

建立了同时检测粮谷中黄曲霉毒素(B1、B2、G1和G2)、玉米赤霉烯酮和赭曲霉毒素A的免疫亲和柱净化-柱后光化学衍生-高效液相色谱方法。样品经过甲醇-水(体积比为80∶20)提取,通过免疫亲和柱富集和净化,采用Waters Nova-Pak色谱柱(3.9 mm i.d.×150 mm,4 μm),以甲醇、乙腈和1%的磷酸溶液为流动相,梯度洗脱,柱后光化学衍生、改变波长荧光检测。黄曲霉毒素(B1、B2、G1和G2)、玉米赤霉烯酮和赭曲霉毒素A检出限分别为0.24,4.0和0.5 μg/kg,标准曲线的线性范围分别为0.24~6.0,4.0~100.0和0.5~40.0 μg/L;在小麦、玉米、黑麦样品中,平均加标回收率为70.8% ~94.0%,相对标准偏差为2.79% ~9.38%。     

多功能柱净化-柱后光化学衍生-高效液相色谱法同时检测玉米和花生中9种真菌毒素

建立了同时检测玉米和花生中黄曲霉毒素B1、B2、G1、G2、M1、M2、玉米赤霉烯酮、呕吐毒素和展青霉素的多功能柱净化-柱后光化学衍生-高效液相色谱检测方法。样品经乙腈-水(体积比为86∶14)提取,多功能净化柱净化,采用C18柱分离,以甲醇、乙腈和水为流动相进行梯度洗脱,在线光化学衍生,以荧光和二极管阵列测器同时检测。黄曲霉毒素B1、B2、G1、G2、M1、M2、玉米赤霉烯酮、呕吐毒素和展青霉素的检出限分别为0.02μg/kg、0.01μg/kg、0.03μg/kg、0.05μg/kg、0.08μg/kg、0.04μg/kg、0.09μg/kg、0.20mg/kg和0.04 mg/kg,在相应浓度范围内线性相关系数均大于0.999,平均加标回收率为80.0%~101.5%,相对标准偏差在1.3%~5.6%之间。该方法简便快速、灵敏度高、重现性好,可满足玉米、花生中9种黄曲霉毒素的检测。     

免疫亲和柱净化-液相色谱-串联质谱法测定中药材中的14种真菌毒素

依次采用磷酸盐缓冲液(PBS)和甲醇-PBS溶液提取样品,以多功能免疫亲和柱净化,采用液相色谱-串联四极杆质谱检测,可同时测定中药材中的黄曲霉毒素B1、黄曲霉毒素B2、黄曲霉毒素G1、黄曲霉毒素G2、伏马毒素B1、伏马毒素B2、T-2毒素、HT-2毒素、赭曲霉毒素A(OTA)、玉米赤霉烯酮等14种真菌毒素。优化条件下,真菌毒素的定量限(LOQ)为1～5 μg/kg, 4种中药材基质(人参、桔梗、板蓝根、麦门冬)中3个不同添加水平的平均回收率(n=6)为71.9%～99.7%,相对标准偏差(RSD)为4.8%～15.8%。该方法的检测速度快,中药材复杂基质的干扰较少,结果准确、可靠,定量限可满足国内外中药材真菌毒素相关限量的要求。     

花生及其制品中多种霉菌毒素残留同时测定方法

利用液相色谱-质谱联用（LC-MS／MS）建立了花生及其制品中多种霉菌毒素包括黄曲霉毒素（B1,B2,G1,G2）、赭曲霉毒素A、伏马毒素B1、脱氧雪腐镰刀菌烯醇、T-2毒素、HT-2毒素及玉米赤霉烯酮的同时测定方法。样品经PBS溶液和甲醇-水溶液提取,提取液经稀释、过滤后,用免疫亲和柱净化,通过淋洗去除免疫亲和柱上的杂质,随后用洗脱液过柱,将目标物分离下来,氮吹干后定容。以液相色谱-质谱／质谱测定,外标法定量。方法的检出限黄曲霉毒素B1为0．0005mg／kg,黄曲霉毒素B2,G1,G2为0．001mg／kg,赭曲霉毒素A为0．002mg／kg,伏马毒素B1为0．020mg／kg,脱氧雪腐镰刀菌烯醇为0．050mg／kg,T-2毒素为0．010mg／kg,HT-2毒素为0．010mg／kg,玉米赤霉烯酮为0．002mg／kg。在样品中添加检出限水平的毒素混标溶液,加标回收率为72．35％-97．82％,测定结果的相对标准偏差为8．95％～18．41％（n=10）.     

电化学衍生-高效液相色谱和荧光光度法检测花生酱中的黄曲霉毒素

建立了免疫亲和柱净化-柱后电化学衍生-高效液相色谱结合荧光光度法检测花生酱中4种黄曲霉毒素(B1、B2、G1和G2)的方法。样品经过体积分数为60%的甲醇提取,通过免疫亲和柱净化后,以KobraCell装置柱后衍生,高效液相色谱法分离定量。黄曲霉毒素B1、B2、G1和G2能达到完全的基线分离,检测限分别为0.5、0.15、0.5和0.15μg/kg,线性相关系数0.999,回收率可达74.2%～96.5%,相对标准偏差低于11%。该方法能够满足花生酱中黄曲霉毒素检测的需要。     

超声萃取-免疫亲和柱净化-柱后光化学衍生高效液相色谱法同时测定蜂房药材中4种黄曲霉毒素

建立超声萃取-免疫亲和柱净化-柱后光化学衍生高效液相色谱同时测定蜂房药材中黄曲霉毒素B1、黄曲霉毒素B2、黄曲霉毒素G1、黄曲霉毒素G2含量的分析方法。样品经粉碎，过孔径为120μm筛后，采用70%甲醇溶液超声处理30 min，经免疫亲和柱净化、高效液相色谱分离、光化学柱后衍生，通过荧光检测器测定4种黄曲霉毒素的含量。黄曲霉毒素B1的线性范围为0.010 4～0.052 0 ng，相关系数为0.999 9；黄曲霉毒素B2的线性范围为0.003 8～0.019 0 ng，相关系数为0.999 8；黄曲霉毒素G1的线性范围为0.010 8～0.054 0 ng，相关系数为0.999 8；黄曲霉毒素G2的线性范围为0.003 8～0.019 0 ng，相关系数为0.999 8。4种黄曲霉毒素检出限分别为0.42、0.15、0.43、0.15μg/kg，测定结果的相对标准偏差不大于2.5%(n=6)，样品加标回收率为92.9%～96.9%。该方法操作简便，灵敏度高，可用于蜂房中黄曲霉毒素含量的测定。     

免疫亲和柱净化-光化学柱后衍生-高效液相色谱法测定柏子仁中的黄曲霉毒素

采用免疫亲和柱净化-光化学柱后衍生-高效液相色谱法测定中药材柏子仁中的黄曲霉毒素G_2、G_1、B_2和B_1。样品经甲醇(7+3)溶液提取,提取液经免疫亲和柱净化,用甲醇洗脱,洗脱液经黄曲霉毒素专用C18色谱柱分离,以甲醇(45+55)溶液为流动相进行洗脱,柱后光化学衍生波长为254nm,荧光检测器的激发波长为365nm,发射波长为440nm。黄曲霉毒素G2、B2的线性范围均为0.125~5.0μg·L~(-1),黄曲霉毒素G_1、B_1的线性范围均为0.50~20μg·L~(-1),检出限(3S/N)在0.012~0.047μg·L~(-1)之间。加标回收率81.4%~105%之间,测定值的相对标准偏差(n=6)在1.6%~6.9%之间。     

光化学柱后衍生–高效液相色谱法测定婴幼儿营养米粉中的黄曲霉毒素B1

建立婴幼儿营养米粉中黄曲霉毒素B1的高效液相色谱荧光检测器测定方法。样品以甲醇–水(体积比70∶30)溶液匀质提取,过黄曲霉毒素B1免疫层析亲和柱净化,经CNW Athena C18色谱柱分离和光化学柱后衍生反应器衍生后,用带有荧光检测器的高效液相色谱仪测定。采用峰面积外标法定量黄曲霉毒素B1含量。黄曲霉毒素B1在0～10μg/L的浓度范围内线性关系良好,相关系数为0.999 8,检出限为0.25μg/kg。在3个添加水平下加标回收率为97.7%～106.9%,测定结果的相对标准偏差为1.7%(n=6)。该方法的灵敏度、准确度、精密度均符合黄曲霉毒素B1的检测技术要求,适用于婴幼儿营养米粉中黄曲霉毒素B1的日常检测。     

液相色谱-串联质谱法测定虾饲料中7种真菌毒素

建立了虾饲料中黄曲霉毒素B_1(AFB_1)、黄曲霉毒素M_1(AFM_1)、T-2毒素(T-2)、HT-2毒素(HT-2)、脱氧雪腐镰刀菌烯醇(DON)、赭曲霉毒素A(OTA)和玉米赤霉烯酮(ZEN)的液相色谱-串联质谱(LC-MS/MS)同时检测方法。样品中加入15 mL乙腈-水(体积比4∶1)和10 mL乙腈饱和正己烷,涡旋混匀,超声提取,MycoSpin~(TM)400多毒素净化柱净化后上机测定。采用Hypersil Gold (150 mm×2.1 mm,5μm)色谱柱进行分离,以甲醇-水(含0.03%氨水)为流动相梯度洗脱,在电喷雾电离模式下正、负离子同时扫描检测,基质匹配外标法定量。在优化条件下,7种真菌毒素的线性相关系数(r~2)均大于0.991,检出限为1.83～12.63μg/kg。在高、中、低3个加标水平下,各目标毒素的回收率为87.5%～116%,相对标准偏差为2.4%～18%。该法可为水产饲料中多种真菌毒素的同时检测提供参考。     

免疫亲和柱净化、在线电化学衍生化高效液相色谱法检测花生中的黄曲霉毒素

 采用免疫亲和柱净化、在线电化学衍生化高效液相色谱法测定了花生中黄曲霉毒素（AFT）B 1,B2,G1和G2。以体积分数为80%的甲醇提取样品中的AFT,经免疫亲和柱净化洗脱 后,以Kobra Cell装置在线衍生,反相HPLC分离定量。4种毒素的分离在13 min内完成,检 出限均达到0.1 μg/kg。5次测定花生样品的RSD值为9.2%～15%;样品添加标样0.5 ～9.0 μg/kg,回收率为74.8%～97.3%。     

Furyl- and thienyl-silatranes and germatranes

We review our research on the synthesis and study of the physical and biological properties of furyl- and thienylgermatranes and -silatranes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 725–732, June, 1992.     

Review and patents and literature

The use of the insect cell/baculovirus expression system for producing recombinant proteins of bacterial, plant, insect, and mammalian origin has become widespread. The popularity of this eukaryotic expression system is due to many factors, including (1) potentially high protein expression levels, (2) ease and speed of genetic engineering, (3) ability to accommodate large DNA inserts, (4) protein processing similar to higher eukaryotic cells (e.g., mammalian cells), and (5) ease of insect cell growth (e.g., suspension growth). The following review of the literature discusses two engineering aspects of recombinant protein synthesis by insect cell cultures: bioreactor scale-up and insect cell line selection. Following this review patent abstracts and additional literature pertaining to expression of recombinant proteins in insect cell culture are listed.     

Ground- and excited-state aromaticity and antiaromaticity in benzene and cyclobutadiene

The aromaticity and antiaromaticity of the ground state (S 0), lowest triplet state (T 1), and first singlet excited state (S 1) of benzene, and the ground states (S 0), lowest triplet states (T 1), and the first and second singlet excited states (S 1 and S 2) of square and rectangular cyclobutadiene are assessed using various magnetic criteria including nucleus-independent chemical shifts (NICS), proton shieldings, and magnetic susceptibilities calculated using complete-active-space self-consistent field (CASSCF) wave functions constructed from gauge-including atomic orbitals (GIAOs). These magnetic criteria strongly suggest that, in contrast to the well-known aromaticity of the S 0 state of benzene, the T 1 and S 1 states of this molecule are antiaromatic. In square cyclobutadiene, which is shown to be considerably more antiaromatic than rectangular cyclobutadiene, the magnetic properties of the T 1 and S 1 states allow these to be classified as aromatic. According to the computed magnetic criteria, the T 1 state of rectangular cyclobutadiene is still aromatic, but the S 1 state is antiaromatic, just as the S 2 state of square cyclobutadiene; the S 2 state of rectangular cyclobutadiene is nonaromatic. The results demonstrate that the well-known "triplet aromaticity" of cyclic conjugated hydrocarbons represents a particular case of a broader concept of excited-state aromaticity and antiaromaticity. It is shown that while electronic excitation may lead to increased nuclear shieldings in certain low-lying electronic states, in general its main effect can be expected to be nuclear deshielding, which can be substantial for heavier nuclei.     

Hard and soft acids and bases: structure and process

Under investigation is the structure and process that gives rise to hard-soft behavior in simple anionic atomic bases. That for simple atomic bases the chemical hardness is expected to be the only extrinsic component of acid-base strength, has been substantiated in the current study. A thermochemically based operational scale of chemical hardness was used to identify the structure within anionic atomic bases that is responsible for chemical hardness. The base's responding electrons have been identified as the structure, and the relaxation that occurs during charge transfer has been identified as the process giving rise to hard-soft behavior. This is in contrast the commonly accepted explanations that attribute hard-soft behavior to varying degrees of electrostatic and covalent contributions to the acid-base interaction. The ability of the atomic ion's responding electrons to cause hard-soft behavior has been assessed by examining the correlation of the estimated relaxation energies of the responding electrons with the operational chemical hardness. It has been demonstrated that the responding electrons are able to give rise to hard-soft behavior in simple anionic bases.     

Determination and study on residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil

A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg^?1, the maximum residue level of European Union for quizalofop-p-ethyl).     

Syntheses and structures of P-anilino-P-chalcogeno- and P-anilino-P-iminodiazasilaphosphetidines and their group 12 and 13 metal compounds

The P-anilino-P-chalcogeno(imino)diazasilaphosphetidines [Me(2)Si(mu-N(t)Bu)(2)P=E(NHPh)] (E = O (3), S (4), Se (5), N-p-tolyl (6)) were synthesized by oxidizing the P-anilinodiazasilaphosphetidine [Me(2)Si(N(t)Bu)(2)P(NHPh)] (2) with cumene hydroperoxide, sulfur, selenium, and p-tolyl azide, respectively. The lithium salt of 4 reacted with thallium monochloride to produce ([Me(2)Si(mu-N(t)Bu)(2)P=S(NPh)-kappaN-kappaS]Tl)(7), which features a two-coordinate thallium atom. Treatment of 4-6 with AlMe(3) gave the monoligand dimethylaluminum complexes ([Me(2)Si(mu-N(t)Bu)(2)P=E(NPh)-kappaN-kappaE]AlMe(2)) (E = S (8), Se (9), N-p-tolyl (10)), respectively. In these complexes the aluminum atom is tetrahedrally coordinated by one chelating ligand and two methyl groups, as a single-crystal X-ray analysis of 8 showed. A 2 equiv amount of 4-6 reacted with diethylzinc to produce the homoleptic diligand complexes ([Me(2)Si(mu-N(t)Bu)(2)P=E(NPh)-kappaN-kappaE](2)Zn)(E = S (11), Se (12), N-p-tolyl (13)). A crystal-structure analysis of 11 revealed a linear tetraspirocycle with a tetrahedrally coordinated, central zinc atom.