血液中苏丹红染料的高效液相色谱分析

采用高效液相色谱法检测血液中苏丹红系列染料(苏丹红Ⅰ～Ⅳ).以镁试剂Ⅱ为内标,用乙腈直接沉淀蛋白,采用Diamonsil C18色谱柱为分析柱,流动相为甲醇-水(体积比94 ∶ 6),流速1.0 mL/min,检测波长480、520 nm.苏丹红Ⅰ ～Ⅳ的线性范围为0.02 ～4.0 mg/L,相关性良好(r=0.999 7),检出限达0.004 mg/L,4种物质的回收率均不低于82%.     

高效液相色谱法测定食品中禁用色素苏丹红Ⅰ-Ⅳ和对位红

采用高效液相色谱法测定食品中禁用色素苏丹红Ⅰ一Ⅳ和对位红.以乙腈为提取剂,超声波提取样品中苏丹红Ⅰ一Ⅳ和对位红.以ZORBAX SB-C18>柱(4.6 mm×150 mm,5μm)为分离柱,乙酸(1 999)溶液和乙腈为流动相进行梯度洗脱,流速为1 mL·min-1,检测波长为485nm的条件下进行检测.苏丹红、对位红的回收率为90%～98%,相对标准偏差小于5%,苏丹红和对位红的检出限均为0.01μg·g-1,苏丹红和对位红的质量浓度在0.2～2.0 mg·L-1范围内呈线性.     

单扫描示波极谱法测定食品中禁用色素苏丹红Ⅰ

在pH 10硼砂缓冲介质中,苏丹红Ⅰ产生一个峰电位在-0.95 V(vs.SCE)的灵敏的吸附还原极谱波.其峰电流的一阶导数值(I'p)与苏丹红Ⅰ的质量浓度在0.1～2.0 mg·L-1范围内呈线性关系,检出限为0.01 mg·L-1.应用此方法分析了辣椒酱及腐乳等试样,均未测出苏丹红Ⅰ,以此试样为基体加入苏丹红Ⅰ标准溶液做回收试验,测得回收率在95.3%～103.0%之间.     

液相色谱-串联质谱法测定浓缩胡萝卜汁中8种苏丹类染料

提出了液相色谱-串联质谱法同时测定浓缩胡萝卜汁中苏丹橙G、苏丹红G、苏丹红7B、苏丹黄、苏丹红Ⅰ、苏丹红Ⅱ、苏丹红Ⅲ、苏丹红Ⅳ等8种苏丹类染料含量的方法。样品经正己烷提取,于39℃旋转蒸发至近干,氮气吹干后用1mL乙腈和0.1%(体积分数,下同)甲酸(1+1)混合液溶解。采用Hypersil GOLD色谱柱(50mm×2.1mm,1.9μm)为分离柱和以不同比例的0.1%甲酸和甲醇混合液为流动相作梯度淋洗,采用多反应监测正离子模式监测。8种苏丹类染料的质量浓度均在30～100μg.L-1范围内呈线性,测定下限(10S/N)在5～30μg.kg-1之间。在3个浓度水平下做加标回收试验,回收率在72.0%～96.0%之间,测定值的相对标准偏差(n=6)在6.2%～9.6%之间。     

高效液相色谱化学发光检测法测定食品中苏丹红Ⅰ

基于碱性条件下,苏丹红Ⅰ对鲁米诺-KIO4发光体系的增敏作用,建立了高效液相色谱化学发光测定苏丹红Ⅰ的新方法。方法采用Phenomenex C18色谱柱(250×4.6mm,5μm),以乙腈∶甲醇∶水=5∶4∶1(V/V/V)为流动相,在0.001～0.50μg/mL范围内,苏丹红Ⅰ浓度与发光强度呈良好的线性关系,相关系数为0.9996,检出限为5ng/kg,相对标准偏差为1.45%(c=0.01μg/mL,n=6),加标回收率为95.0%～104.0%。该法灵敏、准确,用于实际样品中苏丹红Ⅰ的测定,结果令人满意。     

基质固相分散液相色谱-串联质谱法检测禽蛋中的苏丹红

应用基质固相分散技术和液相色谱-串联质谱法(LC-MS/MS)测定了禽蛋中的苏丹红Ⅰ、Ⅱ、Ⅲ、Ⅳ染料.制备样品后装柱,用氯仿-乙腈(体积比为90∶10)混合溶剂洗脱,洗脱液浓缩定容后经ZORBAX SB-C18柱分离,采用电喷雾正离子多反应监控(MRM)模式质谱检测,外标法定量.苏丹红Ⅰ、Ⅱ、Ⅲ、Ⅳ的线性范围分别为0.5～100 ng/g,5.0～100 ng/g,1.0～100 ng/g和2.0～100 ng/g,线性方程的相关系数均大于0.99.样品的添加回收率在87.3%～113%之间,相对标准偏差均小于9.1% .4种苏丹红染料的检测低限分别为0.1,2.0,0.2,0.4 μg/kg,可以满足国内外禽蛋中苏丹红的监控要求.     

反相高效液相色谱法同时测定咸鸭蛋黄中的斑蝥黄和苏丹红

采用反相高效液相色谱法同时测定了咸鸭蛋黄中的斑蝥黄和苏丹红。以乙腈-甲醇-氯仿(体积比为1∶0.5∶0.5)混合溶液提取咸鸭蛋黄中的斑蝥黄和苏丹红。提取液经减压蒸馏至近干,用乙腈定容。以乙腈-水(体积比为95∶5)为流动相,经XDB-Ｃ18色谱柱(250 mm×4.6 mm)分离,采用478 nm～520 nm~471 nm三段变波长检测,获得了较好的分离效果和较低的检测限。将该法用于咸鸭蛋黄中斑蝥黄和苏丹红的测定,苏丹红Ⅰ、苏丹红Ⅱ、苏丹红Ⅲ、苏丹红Ⅳ和斑蝥黄的回收率分别为97.34%,89.56%,90.98%,93.63%和95.15%;相对标准偏差分别为2.7%,4.3%,5.1%,4.9%和3.1%。该法简便、快速、准确。     

等色吸收荧光猝灭法快速测定食品中苏丹红Ⅰ

在乙醇介质中, 强荧光染料吖啶的荧光波长478 nm与苏丹红Ⅰ的吸收光波长480 nm十分接近, 由于等色性苏丹红Ⅰ能够有效吸收吖啶发出的荧光, 使吖啶在激发波长λex=410 nm、荧光波长λem=478 nm处荧光猝灭, 依此建立了荧光猝灭测定苏丹红Ⅰ的新方法. 该方法快速、简便, 其线性范围为3.72～37.2 mg/L, 方法检出限为1.1 mg/L. 用于辣椒、辣椒酱食品中痕量苏丹红Ⅰ的测定. 6次平行测定, 相对标准偏差为0.8%～2.7%, 加标回收率为89.5%～104.0%.     

凝胶净化/超高效液相色谱电喷雾质谱法检测调味油中11种禁用偶氮染料及罗丹明B

建立了凝胶渗透色谱(GPC)净化/超高效液相色谱-电喷雾串联四极杆质谱(UPLC-MS/MS)同时检测调味油中11种脂溶性偶氮类工业染料(苏丹红Ⅰ、苏丹红Ⅱ、苏丹红Ⅲ、苏丹红Ⅳ、苏丹红7B、苏丹红G、苏丹黄、苏丹橙G、苏丹蓝Ⅱ、甲苯胺红、对位红)和罗丹明B的分析方法。样品经乙酸乙酯-环己烷(1∶1)提取,采用凝胶渗透色谱(GPC)去除大分子油脂、天然色素等干扰物质;以乙腈-0.1%甲酸为流动相,目标化合物在梯度洗脱条件下经C18柱分离后采用多离子反应监测(MRM)正离子模式进行检测。结果表明:调味油中12种工业染料的线性范围为1～50μg/L,定量下限(LOQ)为0.2～2.5μg/kg,在5、20、40μg/L 3个加标水平下的回收率为54%～125%,相对标准偏差为2.5%～17.2%。随机抽取市售35份样品进行检测,其中两份样品检出罗丹明B。该方法操作简便、灵敏度高,实现了11种禁用偶氮染料和罗丹明B的同时提取和净化,适合于调味油中非法添加脂溶性偶氮工业染料和罗丹明B的筛查与确证。     

液相色谱-串联质谱法快速检测番茄制品中苏丹红

采用HPLC/MS-MS鉴定和检测番茄制品中苏丹红染料Ⅰ～Ⅳ。番茄制品中苏丹红Ⅰ、Ⅱ、Ⅲ、Ⅳ,经正己烷加乙酸溶液提取,氧化铝柱净化,再用二氯甲烷洗脱苏丹红,经浓缩至干,流动相定容,液相色谱串联质谱测定,外标法定量。将已用HPLC法测定过的10个可疑样品,用该方法进行检测,结果有4个检了苏丹红Ⅰ。采用本方法检测苏丹红Ⅰ～Ⅳ,检测限均可达到1.0μg/kg,在添加浓度1～100μg/kg之间线性关系良好,相关系数(r)均>0.9990,对于1、5、10μg/kg水平添加回收率在72.3%～103%之间,相对标准偏差在2.5%～9.8%之间。     

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.