格氏试剂衍生-气相色谱-串联质谱法同时测定水果和蔬菜中的三环锡、三苯锡和苯丁锡残留

建立了水果和蔬菜中三环锡、三苯锡和苯丁锡同时检测的格氏试剂衍生-气相色谱-串联质谱方法（GC-MS/MS）。样品经盐酸/四氢呋喃（1：10,v/v）消解,正己烷振荡提取,乙基溴化镁衍生和Florisil固相萃取净化,采用GC-MS/MS多反应监测（MRM）模式对3种有机锡化合物进行定性和定量分析。实验结果表明,以苹果为代表性样品基质,三环锡、三苯锡和苯丁锡的检出限（LOD）分别为2.0、1.5和3.4 μg/kg （以Sn计）,在10、20、50、200 μg/kg （以Sn计）共4个添加水平下的平均回收率为72.4%~107.1%,相对标准偏差为0.4%~14.2%。该方法灵敏度高,选择性强,可以实现3种有机锡农药的同时检测,能够满足国内外残留限量的检测要求。     

气相色谱-质谱法测定油炸淀粉类食品中的丙烯酰胺

 建立了油炸淀粉类食品中丙烯酰胺的溴衍生化气相色谱-质谱(GC-MS)测定方法。样品经水提取、高速离心、石墨化 炭黑柱净化、溴衍生化后,以GC-MS选择离子进行定性,同位素稀释技术定量。该方法的检出限为5 μg/kg,回收率为90％ ～105％,相对标准偏差为6.3％。利用该方法对市场上某些油炸淀粉类食品进行了初步测定,发现薯片和炸薯条中含有27 8~4518 μg/kg的丙烯酰胺。     

同位素稀释气相色谱-谱法快速测定酱油中3-氯-，2-二醇量

采用同位素稀释气相色谱－质谱联用（GC－MS）法，快速测定酱油中3－氯－1，2-丙二醇（3-MCPD）的含量。试样中加入3－氯－1，2-丙二醇的氘代同位素作为内标，经超声混匀后加入到自行填装的弗罗里硅土柱中，以乙醚洗脱，洗脱液经氮气吹干后在正己烷溶剂中进行衍生化，衍生化试剂采用七氟丁酰咪唑。GC-MS采用选择离子监测（SIM）模式进行定性定量分析。结果表明，本方法的添加回收率为95．0％－101．0％；相对标准偏差为3．2％～4．8％；检出限达到0．010mg／kg。本方法步骤简单，溶剂用量少，定性定量准确可靠。可快速测定酱油等调味品中3－氯－1，2-丙二醇的含量。     

QuEChERS/超高效液相色谱-四极杆-飞行时间质谱法筛查鲜桃中的农药残留

采用QuEChERS前处理技术结合超高效液相色谱-四极杆-飞行时间质谱（UPLC-QTOF MS）筛查了鲜桃中的农药残留。鲜桃均质后经1%乙酸乙腈提取，加入无水醋酸钠和无水硫酸镁，以PSA和石墨化炭黑（Carb）净化，利用UPLC-QTOF MS进行数据采集，经UNIFI软件进行峰谱识别后，利用自建农药谱库进行检索筛查。在23份鲜桃中检出33种农药，其中杀虫剂占49%，抗菌剂占33%，其余为除草剂和植物生长调节剂。所有样本中均筛查出一种或多种农药，其中18种农药有国家限量标准，2份鲜桃中的抗菌剂多菌灵和氟硅唑分别超过标准限量。研究表明UPLC-QTOF MS高分辨质谱技术是筛查水果中农药残留的有效手段，鲜桃中存在多种农药残留，需进一步对其残留水平和暴露风险进行研究。     

快速滤过型净化结合气相色谱-串联质谱法同时检测茶叶中10种拟除虫菊酯农药残留

建立了快速滤过型净化（m-PFC）结合气相色谱-串联质谱（GC-MS/MS）测定茶叶中10种拟除虫菊酯类农药残留的方法。比较了采用不同提取溶剂（乙腈、丙酮和乙酸乙酯）和不同提取方式（不加水浸泡和加水浸泡）时10种农药的提取效率；比较了2种QuEChERS净化管和m-PFC柱对茶叶提取液的净化效果和农药残留的回收率。结果表明，茶叶样品不加水浸泡，用乙腈提取效果最好；m-PFC柱对茶叶提取液净化效果良好，而且能保证较高的农药回收率。10种拟除虫菊酯农药在相应的范围内有良好的线性关系，相关系数（R²）大于0.9980；10种农药在4个水平添加下的回收率为87.5%~111.3%，RSD为2.1%~8.9%。方法的检出限为0.001~0.015 mg/kg，定量限为0.003~0.05 mg/kg。利用该方法检测市售50例茶叶样品中10种拟除虫菊酯农药的残留，检出率为48%，但农药残留量均在国家标准限量值以下。与传统QuEChERS法和固相萃取法相比，该方法具有操作简单、准确度和精密度良好等优点，为多种拟除虫菊酯类农药在茶叶中的残留测定提供了快速检测的新方法。     

在线凝胶渗透色谱/气相色谱-质谱联用法测定水果中11种苯氧羧酸类农药

建立了水果中11种苯氧羧酸类农药多残留的在线凝胶渗透色谱/气相色谱-质谱(GPC/GC-MS)分析方法。样品经丙酮-正己烷溶液超声提取,提取液浓缩、干燥后用正丁醇-硫酸溶液衍生,再用Florisil固相萃取柱和在线GPC净化,GC-MS选择离子监测模式(SIM)进行检测和确证。结果显示,11种苯氧羧酸类农药在0.01～1.0 mg/L范围内线性关系良好,相关系数为0.998 7～0.999 9;在0.02～0.10 mg/kg加标范围内,回收率为66%～112%,相对标准偏差为3.4%～11.5%,11种苯氧羧酸类农药的定量下限为7～10μg/kg。该方法简便、快速、灵敏、净化效果好,可满足国际上对水果中多种苯氧羧酸类农药残留分析的要求。     

纺织品中游离甲醛的气相色谱-质谱法测定

1引言 脲醛树脂在改善纺织品的抗皱、防水、阻燃、耐压性能以及提高色牢度方面有显著效果,但其所含甲醛在服饰穿着过程中会从织物面料中释放出来.有关纺织品游离和水解甲醛测定的标准（ISO/FDIS14184-1）只适用于游离甲醛含量为20～3500 mg/kg的纺织品.对A类产品（婴幼儿用品）甲醛含量临近阈值（20 mg/kg）的检测结果,易造成假阳性结果.本研究将织物样品甲醛衍生化后借助顶空-固相微萃取（HS-SPME）超声提取衍生化产物醛腙,利用GC-MS选择离子检测方法（SIM）定量,方法适用于各类单层或多层纤维织物中甲醛的测定.     

衍生化-气相色谱-三重四极杆质谱法同时测定粮食作物中三氯甲基吡啶及其代谢物残留

建立了粮食作物中三氯甲基吡啶及其代谢物6-氯吡啶甲酸的衍生化-气相色谱-三重四极杆质谱（GC-MS/MS）检测方法。选取高粱、小麦、玉米及爆谷等典型的粮食作物,采用酸性乙腈提取,以浓硫酸作为三氯甲基吡啶代谢物的衍生化试剂,优化了衍生化反应的最佳反应条件,并使用GC-MS/MS分析,以内标法对三氯甲基吡啶及其代谢物进行定量检测。结果表明,在0.025~0.4 mg/L范围内,线性关系良好,相关系数（r²）均大于0.995,在3个不同添加水平下的平均回收率在80.4%~98.4%之间,相对标准偏差（RSD）在1.0%~10.1%之间。该方法操作简单、高效,灵敏度高,抗干扰能力强,回收率和重复性良好,能够满足粮食作物中三氯甲基吡啶及其代谢产物残留量的检测要求。     

羰基铁粉掺杂整体柱萃取-在线热解吸进样气相色谱-串联质谱法分析茶叶样品中拟除虫菊酯类农药残留

制备了羰基铁粉掺杂硅胶整体柱，用于拟除虫菊酯类农药残留萃取，并与气相色谱-串联质谱（GC-MS/MS）法联用，建立了在线富集、热解吸GC-MS/MS测定茶叶样品中拟除虫菊酯类农药残留方法。研究将端羟基聚二甲基硅氧烷共价键合到SiO₂网络表面，并同时键合羰基铁粉。将目标分析物吸附并浓缩在聚二甲基硅氧烷位点上后，利用羰基铁粉的高频感应加热特性成功实现了GC-MS/MS直接气体进样并可达到快速、均匀解吸的目的。实验结果表明，在最佳条件下，本方法的富集倍数可达到约1000倍。拟除虫菊酯类农药残留的检出限为3.8~7.5 μg/kg，相对标准偏差为3.2%~6.8%（n=6）。该方法的提取回收率为97.7%~110.5%，相关系数≥0.9960。该法的吸附容量大，在电磁感应的条件下进行热脱附继而直接与GC-MS结合实现在线分析以及无溶剂洗脱。与常规固相微萃取（SPME）方法相比，该方法具有富集因子高、整体柱吸附容量大、可重复使用、自动化程度高、普适性好等优点。在样品前处理及复杂基质中农药残留的提取方面具有重要的研究意义。     

气相色谱-质谱法测定富硒酵母中的硒蛋氨酸

建立了气相色谱-质谱（GC-MS）测定富硒酵母中硒蛋氨酸含量的方法。比较了3种从样品中提取硒蛋氨酸方法的效果。样品在三羟甲基氨基甲烷（Tris）缓冲液中酶解24 h后,以丁醇及三氟乙酸酐为衍生化试剂对硒蛋氨酸进行衍生化,采用选择离子模式对衍生物进行GC-MS测定。硒蛋氨酸的回收率为98.5%~103.7%,相对标准偏差为0.9%~2.4%,检出限为0.5 mg/L（S/N=3）。对实际样品进行测定,得到样品中硒蛋氨酸的含量结果。该法简便快速,准确可靠,灵敏度高。     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.