气相色谱法测定常见饮料中8种邻苯二甲酸酯类化合物

为了解我国市售瓶装饮料中邻苯二甲酸酯类环境污染物的迁移情况,采用气相色谱法测定市售塑料瓶装饮料中的邻苯二甲酸二甲酯、邻苯二甲酸二乙酯、邻苯二甲酸二丁酯等8种邻苯二甲酸酯类化合物(PAEs)。样品经正己烷萃取并浓缩后,采用直接进样法分析,经HP–5毛细管色谱柱分离后用氢火焰离子化检测器检测。8种邻苯二甲酸酯类化合物的质量浓度在0.25～100μg/mL范围内与其色谱峰面积呈良好的线性关系,线性相关系数均大于0.997,检出限均为0.05μg/mL。三水平加标回收率为91.2%～109.0%,测定结果的相对标准偏差为1.2%～3.4%(n=6)。用该方法对14种饮料进行检测,其中有一种或几种PAEs检出,且酸性饮料中PAEs溶出量较大,暴晒后饮料中PAEs的总量增高。该方法操作简单,选择性和准确度较好,可用于饮料中PAEs的检测。     

高效液相色谱测定牛奶中邻苯二甲酸酯的方法研究

建立了针对欧盟指令2007/19/EC中禁止与食品接触的6种邻苯二甲酸酯(BBP、DBP、DEHP、DNOP、DINP和DIDP)的RP-HPLC测定方法.样品用甲醇、正己烷.甲基叔丁基醚(ⅥV=1:1)提取,经冷冻去脂、液液萃取和硅胶固相萃取净化后,用ODS柱(250×4.6mm,5μm)分离,UV 224 nm检测.结果表明,BBP和DBP在0.05～80μg/mL、DEHP和DNOP在0.1～80μg/mL、DINP和DIDP在0.5～80μg/mL的质量浓度范围内,峰面积与质量浓度呈线性关系,相关系数(r2)均大于0.998.方法检测限分别为:BBP 0.15μg/g、DBP 0.1μg/g、DEHP和DNOP 0.2μg/g、DINP和DIDP 0.6μg/g;6种PAEs的添加量在最大残留限量值的0.2、1和2倍时,其平均回收率为80.7%～102.3%,相对标准偏差为1.7%～9.0%.所建立的方法经济、准确、可靠,满足欧盟指令中6种邻苯二甲酸酯限量的检测要求.     

气相色谱法测定茶叶中邻苯二甲酸酯

建立了同时检测茶叶中5种邻苯二甲酸酯类(PAEs)的气相色谱(GC)-氢火焰离子(FID)检测方法,并对市售部分茶叶中的PAEs含量进行了测定。茶叶样品采用同时蒸馏萃取,处理后以HP-5石英毛细管柱分离,GC-FID法进行检测,外标法定量。5种PAEs在各自检测浓度范围内线性关系良好,其线性相关系数均达到0.999以上,检出限(LOD)为2.63~8.42μg/L,加标回收率在78.2%~111.3%之间,相对标准偏差(RSD)均小于5%,方法可以满足实际茶叶样品中5种PAEs的分析检测。     

GPC-GC/MS法测定食用油中17种邻苯二甲酸酯的方法研究及其不确定度评估

建立用凝胶渗透色谱净化-气相色谱/质谱分析食用油中17种邻苯二甲酸酯类(PAEs)增塑剂的方法并对其不确定度进行评估。样品用环己烷-乙酸乙酯稀释,稀释液经凝胶柱净化后,采用气相色谱-质谱在选择离子检测(SIM)模式下进行定性定量分析并计算其不确定度。结果表明,除DINP外16种邻苯二甲酸酯都有较低的检出限(0.1μg/mL);对于17种增塑剂均有较好的精密度(RSD3%);17种增塑剂在1~8mg/L范围内线性关系良好;除苯酯、DNOP、DNP外其余邻苯二甲酸酯类均有较好回收率;扩展不确定度在1.58%~4.60%之间。因此,本法适用于食用油中PAEs的测定。     

GPC-GC/MS法测定食用油中17种邻苯二甲酸酯的方法及其不确定度评估

建立用凝胶渗透色谱净化-气相色谱/质谱分析食用油中17种邻苯二甲酸酯类(PAEs)增塑剂的方法并对其不确定度进行评估。样品用环己烷-乙酸乙酯稀释,稀释液经凝胶柱净化后,采用气相色谱-质谱在选择离子检测(SIM)模式下进行定性定量分析并计算其不确定度。结果表明,除DINP外16种邻苯二甲酸酯都有较低的检出限(0.1μg/mL);对于17种增塑剂均有较好的精密度(RSD3%);17种增塑剂在1~8mg/L范围内线性关系良好;除苯酯、DNOP、DNP外其余邻苯二甲酸酯类均有较好回收率;扩展不确定度在1.58%~4.60%之间。因此,本法适用于食用油中PAEs的测定。     

液液萃取/气相色谱－质谱法测定氟［18F］脱氧葡糖注射液塑料生产组件浸提液中16种邻苯二甲酸酯类增塑剂

建立了基于液液萃取（LLE）/气相色谱－质谱（GC－MS）检测氟［18F］脱氧葡糖注射液塑料生产组件浸提液中16种邻苯二甲酸酯类（PAEs）增塑剂的方法。根据生产工艺,采用含5%乙醇、5%乙腈的混合溶液作为模拟溶剂,在40 ℃条件下进行模拟浸提。采用Thermo TG－5 SIL MS色谱柱分离,选择离子扫描模式（SIM）进行分析。通过对仪器条件与萃取条件进行优化,确定最佳前处理方法和仪器条件。在优化实验条件下,16种PAEs在50～500 ng/mL范围内与峰面积呈良好的线性关系,相关系数（r）均不小于0.990 6,检出限（LOD）和定量下限（LOQ）分别为10、30 ng/mL。以二氯甲烷为萃取溶剂时,平均回收率为83.0%～114%,相对标准偏差（RSD,n = 6）为1.9%～4.2%。采用该方法对浸提液进行测定,16种PAEs均未超过分析评价阈值（AET）。该法操作简便,专属性强,可用于氟［18F］脱氧葡糖注射液塑料生产组件的相容性研究。     

分散固相萃取技术分析油脂类食品中塑化剂含量

建立了含油脂食品样品中的15种邻苯二甲酸酯类(PAEs)物质的检测方法。采用分散固相萃取(DSPE)方法,经正己烷、乙腈提取,N-苯基乙二胺(PSA)净化,并用气质联用仪定性定量检测。结果表明,在优化条件下,15种邻苯二甲酸酯的标准曲线线性范围为0.2～10 mg/L,加标样品在0.5和5.0 mg/L水平浓度下的回收率都在78%～113%范围内,相对标准偏差为1.5%～7.3%,检出限为0.03～0.5 mg/L(S/N=3)。本方法性能可靠、重复性好,回收率高,适用于含油脂食品中PAEs的痕量分析。     

高效液相色谱-串联质谱法测定焙烤食品及其塑料包装中31种邻苯二甲酸酯

建立了高效液相色谱-三重四极杆串联质谱（HPLC-MS/MS）测定焙烤食品及其塑料包装中31种邻苯二甲酸酯（PAEs）的方法。焙烤食品采用乙酸乙酯超声提取,提取液经冷冻（-18℃）、低温高速离心净化,剪碎后的塑料包装材料采用体积比为1：1：1的甲醇-丙酮-正己烷混合溶剂进行液液超声萃取后进入HPLC-MS/MS分析。采用MGⅢC₁₈色谱柱（2.0 mm×100 mm,5 μm）,选择反应监测（SRM）模式测定。实验结果表明,31种邻苯二甲酸酯的特征离子质量色谱峰的峰面积与其质量浓度在各自的质量浓度范围内线性关系良好（r²≥0.9958）。样品加标回收率除邻苯二甲酸二月桂酯（DLP）为70.9%～109.7%外,其余30种化合物为80.1%～113.0%,相对标准偏差（n=6）为1.0%～13.7%。31种PAEs的检出限在0.02～8.15 μg/kg之间,定量限在0.07～27.17 μg/kg之间。应用该方法检测了面包、饼干、糕点、馅料4大类焙烤食品及其塑料包装中31种邻苯二甲酸酯的含量。该方法具有操作简单、快速、准确度和精密度高等优点,满足日常检测的要求。     

气相色谱-负化学电离质谱法测定塑料中十七种邻苯二甲酸酯

建立了气相色谱-负化学电离质谱法(GC-NCI/MS)同时测定塑料中17种邻苯二甲酸酯(PAEs)的分析方法。塑料样品经二氯甲烷超声提取并过滤后进行检测。采用HP-5 MS毛细管色谱柱在程序升温条件下对滤液进行色谱分离,质谱采用负化学电离(NCI)模式,反应气采用氨气。17种PAEs在0.05~3.5 mg/L范围内线性关系良好,相关系数(r)均大于0.995;检出限为0.018~2.162 mg/kg;在100,500,1000,5000 mg/kg 4个添加水平下,17种PAEs的平均加标回收率为95.8%~106.5%,RSD(n=6)为2.6%~7.9%。方法可用于塑料产品中17种邻苯二甲酸酯的检测。     

GC-MS同时测定油脂性的食品及食品添加剂中16种邻苯二甲酸酯类迁移物

采用气相色谱电子轰击离子源质谱(GC-EI-MS)技术同时分析油脂性食品及油脂性添加剂中16种邻苯二甲酸酯(PAEs)环境激素的迁移量。以GC-EI-MS选择离子检测模式(SIM)进行定性和定量分析,优化出了油脂性基质的系统前处理方法。当样品的加标浓度水平分别为0.25和0.50 mg/kg时,加标回收率为58.9%～111.1%,相对标准偏差为1.0%～4.6%。16种PAEs在0.1～2.0 mg/L浓度范围内16种PAEs都呈现良好的线性关系,r为0.9960～0.9995,检测限(LOD)均为0.07～0.70μg/kg。方法已用于8批油脂性的食品和7批油脂性食品添加剂中16种痕量PAEs迁移物的分析。     

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.     

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%).     

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.     

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.