高效液相色谱-串联质谱法测定冷冻饮品中的5种季铵盐

建立了快速测定冷冻饮品中5种季铵盐(十二烷基二甲基苄基氯化铵、十四烷基二甲基苄基氯化铵、十六烷基二甲基苄基氯化铵、十六烷基二甲基苄基氯化铵、十二烷基三甲基氯化铵和双癸基二甲基氯化铵)的高效液相色谱-串联质谱(HPLC-MS/MS)检测方法。样品经乙腈-乙酸乙酯(1∶1,体积比)提取2次,提取液于-20℃冷冻脱脂净化,经CAPCELL PAK CR(1∶20)色谱柱分离,以乙腈-5 mmol/L乙酸铵(含0.1%甲酸)水溶液为流动相,梯度洗脱,采用多反应监测(MRM)模式,基质外标法进行定量分析。结果表明,5种季铵盐在0.5～50.0μg/L质量浓度范围内线性关系良好,相关系数(r)均大于0.995。5种季铵盐的检出限为0.3～1.5μg/kg,定量下限为1.0～5.0μg/kg。样品基质在5.0、10.0和50.0μg/kg 3个加标水平下的平均回收率为80.3%～114%,相对标准偏差(RSD)为2.5%～8.3%。实际样品检测结果表明,冷冻饮品中存在季铵盐的残留污染。该方法操作便捷,灵敏度高,精密度良好,适用于冷冻饮品中5种季铵盐的定量检测。     

固相萃取-高效液相色谱-串联质谱法同时测定牛奶中多种季铵类化合物残留

建立了快速测定牛奶中季铵类化合物多残留的固相萃取-高效液相色谱-串联质谱法。以乙腈提取目标化合物,弱阳离子固相萃取柱萃取净化,氮吹浓缩处理,C18色谱柱分离,0.1%乙酸-20 mmol/L乙酸铵甲醇溶液梯度洗脱,多反应监测正离子模式扫描。目标化合物在7 min内实现良好分离,并在各自相应浓度范围内线性良好,相关系数>0.99,方法的定量限:十二烷基二甲基苄基溴化铵、十四烷基三甲基溴化铵、十四烷基二甲基苄基氯化铵和双十烷基二甲基溴化铵为0.2μg/kg;十六烷基三甲基溴化铵为1.0μg/kg。在2.0,10和20μg/kg添加浓度,目标化合物在纯牛奶、鲜牛奶和低脂牛奶中的平均回收率分别为70.5%~96.6%,69.1%~87.9%和67.1%~93.3%,相对标准偏差为1.4%~11.6%。本方法操作简便,灵敏度高,适用于牛奶中季铵类化合物多残留的快速检测。     

固相萃取/高效液相色谱-串联质谱法同时检测多类食品中二甲基黄、二乙基黄含量

建立了豆干、辣椒酱、豆腐乳、腐竹和饼干等样品中二甲基黄和二乙基黄残留量的液相色谱-串联质谱分析方法。基于二甲基黄和二乙基黄的化学结构特性,采用乙腈溶液提取。提取液酸化后经Bond Elut Plexa PCX阳离子交换树脂固相萃取净化,吹干复溶后,使用反相C_(18)色谱柱分离,电喷雾串联四极杆质谱正离子化多反应监测(MRM)模式检测。二甲基黄和二乙基黄的方法定量下限均为0.50μg/kg。对5种不同基质样品进行二甲基黄和二乙基黄0.50,5.0,80μg/kg 3个浓度水平的加标回收实验,得到二甲基黄和二乙基黄的平均回收率分别为76.4%~93.0%和76.1%~92.4%;相对标准偏差分别为1.7%~6.3%和1.9%~7.4%,可以满足食品中二甲基黄和二乙基黄快速筛查和定量分析的要求。     

高效液相色谱-串联质谱法测定豆芽中8种药物残留

建立了豆芽中8种药物(4-氯苯氧乙酸、吲哚乙酸、吲哚丁酸、1-萘乙酸、6-苄基腺嘌呤、2,4-二氯苯氧乙酸、赤霉素和多菌灵)残留的高效液相色谱-串联质谱(LC-MS/MS)检测方法。豆芽样品经0.1%冰醋酸-乙腈溶液提取、浓缩,分散固相萃取剂净化后,用液相色谱-串联质谱测定,外标法定量。8种药物在5~100μg/L范围内呈良好的线性关系(r20.99),定量下限为5μg/kg。在5,10,20μg/kg 3个加标水平下,8种药物的回收率为71.6%~87.9%,相对标准偏差不大于14.6%。方法准确、简单、快速,可用于豆芽中8种药物的同时测定。     

反相液相色谱-二极管阵列法测定消毒产品中苯扎氯铵3种同系物的含量

目前标准方法检测苯扎氯铵时仅用了一个平均相对分子质量洁尔灭来表示两种或几种混合物,无法区别苯扎氯铵的几种同系物,为了测定苯扎氯铵同系物的含量,进行了题示研究。取消毒产品1.000 0 g,用水稀释并定容至10 mL,超声提取5 min,静置,过0.45μm聚砜醚水相滤膜,滤液中苯扎氯铵3种同系物十二烷基二甲基苄基氯化铵、十四烷基二甲基苄基氯化铵、十六烷基二甲基苄基氯化铵在Agilent XDB-C₁₈色谱柱(250 mm×4.6 mm, 5μm)上分离,以体积比70:30的乙腈-含0.1%(体积分数)三乙胺的0.5 g·L^-1乙酸铵缓冲溶液(pH 5.0)为流动相进行等度洗脱,采用二极管阵列检测器在262 nm处检测。结果表明,扫尾剂三乙胺的体积分数从1%降低到0.1%,避免了扫尾剂三乙胺对色谱柱的可能损害,解决了出现鬼峰的问题。苯扎氯铵3种同系物的质量浓度在10～500 mg·L^-1内与对应的峰面积呈线性关系,检出限(3S/N)分别为1.1,1.2,1.5 mg·L^-1。按照标准加入法进行回收试验...     

通过式固相萃取-超高效液相色谱-串联质谱法测定婴幼儿配方奶粉中的10种季铵盐类消毒剂残留北大核心CSCD

建立了通过式固相萃取净化-超高效液相色谱-串联质谱法测定婴幼儿配方奶粉中的10种季铵盐类消毒剂(QACs)残留的方法。样品经水溶解后,用含0.2%甲酸的乙腈提取,提取液用甲醇1∶1混匀,用通过式固相小柱(Oasis PRiME HLB)净化,流动相由含0.2%甲酸的甲醇-乙腈溶液(体积比,6∶4)与含0.2%的甲酸水溶液组成。10种QACs在Waters CORTECS UPLC C18(100 mm×2.1 mm,1.6μm)色谱柱上以梯度洗脱分离后,采用电喷雾离子源正离子(ESI+)模式电离,配合多反应监测模式(MRM)进行定性定量分析。结果表明,10种QACs在各自浓度范围内线性良好,相关系数r^(2)≥0.9964,方法定量限(LQD)为0.5~3.0μg/kg。采用低、中、高3个浓度水平进行加标实验,回收率范围为86.2%~103.4%。方法简单高效,可作为日常婴幼儿配方奶粉监督抽样中10种季铵盐类消毒剂(QACs)残留检测的有效方法。     

高效液相色谱-示差折光检测器法测定复配消毒液中3种双链季铵盐的含量

提出了高效液相色谱-示差折光检测器法测定复配消毒液中二癸基二甲基氯化铵、辛基癸基二甲基氯化铵、二辛基二甲基氯化铵等3种双链季铵盐含量的方法。复配消毒液样品经流动相稀释,以Welchrom C₁₈色谱柱为固定相,以体积比70:30的乙腈-0.01 mol·L^-1丁烷磺酸钠溶液的混合溶液(pH 3.5)为流动相进行洗脱,采用示差折光检测器测定3种双链季铵盐的含量。结果表明：3种双链季铵盐的质量浓度在50～1 000 mg·L^-1内与对应的峰面积呈线性关系,检出限(3S/N)为3.3～5.1 mg·L^-1;对实际样品进行3个浓度水平的加标回收试验,回收率为91.0%～105%,测定值的相对标准偏差(n=6)为1.3%～2.2%。采用独立样本t检验法比对本方法与高效液相色谱-蒸发光散射检测器法是否具有显著性差异,结果显示两组检测结果t值为1.85,P值为0.089,表明无显著性差异。     

液液萃取-气相色谱/质谱法同时测定水中3种季胺盐化合物

建立了液液萃取-气相色谱/质谱同时测定水中3种典型季胺盐化合物十二烷基三甲基氯化铵(DTAC)、十六烷基三甲基溴化铵(CTAB)、双十二烷基二甲基氯化铵(DDAC)的分析方法。采用电子轰击(EI)-选择离子模式(SIM)进行定性与定量分析,DTAC和CTAB的特征离子为m/z 58,DDAC的特征离子为m/z 212。考察了萃取剂种类、萃取次数、pH值以及盐度对萃取效率的影响。以HCl及30%NaCl溶液调节水样pH值为1.5及盐度为3%,以5 mL三氯甲烷萃取2次,3种目标化合物的线性范围在0.01~2.0 mg/L之间,检出限LOD(S/N=3)为2.5~8.5μg/L。以此方法测定自来水、湖水、河水、选矿废水样品,3种目标化合物的含量在0.06~2.45 mg/L之间,不同加标水平(0.2,0.5和1.0 mg/L)回收率在65%~113%之间,相对标准偏差在3.8%~23.0%之间。     

十二烷基二甲基苄基氯化铵从碱性氰化液中固相萃取金的研究

建立了一种用十二烷基二甲基苄基氯化铵(BDMDAC)从碱性氰化液中固相萃取金的新方法:在碱性介质中,十二烷基二甲基苄基氯化铵溶液(BDMDAC)与Au(CN)2-络阴离子生成离子缔合物,该离子缔合物可被反相键合硅胶固相萃取柱萃取、富集,用乙醇洗脱,反相键合硅胶固相萃取柱可重复使用。该方法用于从碱性氰化液中固相萃取痕量金,萃取回收率可超过98%。     

液相色谱-串联质谱法测定育肥猪配合饲料中的阿奇霉素

通过对提取溶剂、净化方法及色谱-质谱条件的优化,建立了配合饲料中阿奇霉素(AZM)的液相色谱-串联质谱测定方法。样品经乙腈超声波提取,MCX固相萃取柱净化,BDS Hypersil C_(18)(2.4μm,100 mm×2.1 mm)色谱柱分离,以甲醇-0.05 mol/L乙酸铵水溶液为流动相梯度洗脱,正离子模式电离,多反应监测模式检测,同位素内标法定量。在优化条件下,AZM在1~250μg/L范围内线性关系良好,相关系数(r~2)为0.999 1,检出限(S/N≥3)为2.8μg/kg,定量下限(S/N≥10)为8.4μg/kg;在0.5,1,5,10 mg/kg加标水平下,回收率为87.0%~106.6%,批内相对标准偏差为0.58%~5.4%,批间相对标准偏差为3.1%~5.4%。该方法准确、灵敏,选择性强,基质干扰小,可用于配合饲料中AZM的测定。     

Darstellung,Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von vier bindungsisomeren Trichlorotrirhodanoosmaten(IV)

Preparation, Crystal Structures, Vibrational Spectra, and Normal Coordinate Analysis of four Linkage Isomeric Trichlorotrirhodanoosmates(IV) By treatment of fac-[OsCl₃I₃]^2? with (SCN)₂ in dichloromethane the linkage isomers fac-[OsCl₃(NCS)₃]^2? ( 1 ), mer-[OsCl₃(NCS)₂^c(SCN)]^2? ( 2 ), mer-[OsCl₃(NCS)(SCN)₂^t]^2? ( 3 ), and mer-[OsCl₃(NCS)(SCN)₂^c]^2? ( 4 ) are formed which have been separated by ion exchange chromatography on diethylaminoethyl cellulose. X-Ray structure determinations have been performed on single crystals of fac-(Ph₄As)₂[OsCl₃(NCS)₃] (triclinic, space group P1 , a = 12.142(5), b = 13.233(5), c = 19.300(5) Å, α = 98.642(5)º, β = 100.509(5)º, γ = 112.514(5)º, Z = 2), mer-(Ph₄As)₂[OsCl₃(NCS)₂^c (SCN)] · acetone (triclinic, space group P1 , a = 11.707(5), b = 13.238(5), c = 19.048(5) Å, α = 75.960(5)º, β = 88.981(5)º, γ = 69.999(5)º, Z = 2), mer-(Ph₄As)₂[OsCl₃(NCS)(SCN)₂ ^t] (triclinic, space group P1, a = 10.6861(12), b = 11.6587(5), c = 12.5232(5) Å, α = 112.069(8)º, β = 95.052(8)º, γ = 92.559(7)º, Z = 1) and mer-(Ph₄As)₂[OsCl₃(NCS)(SCN)₂ ^c] · 2acetone (triclinic, space group P1 , a = 11.444(5), b = 14.661(5), c = 15.830(5) Å, α = 75.790(5)º, β = 80.273(5)º, γ = 75.205(5)º, Z = 2). The complex anions are completely ordered. The via N or S coordinated thiocyanate groups are located nearly direct above one of the cis-positioned Cl ligands with Os? N? C angles of 169.1º, 171.5º, 175.7º ( 1 ), 175.6º, 178.6º ( 2 ), 172º ( 3 ), and 173.1º ( 4 ) and Os? S? C angles of 106.2º ( 2 ), 106.1º, 106.6º ( 3 ), 105.1º, and 108.2º ( 4 ). Using the molecular parameters of the X-Ray determinations the low temperature (10 K) IR and Raman spectra of the (n-Bu₄N) salts of all four linkage isomers have been assigned by normal coordinate analyses based on a modified valence force field. The valence force constants are f_d(OsN) = 1.71 ( 1 ), 1.46 and 1.62 ( 2 ), 1.69 ( 3 ), and 1.61 ( 4 ), f_d(OsS) = 1.27 ( 2 ), 1.36 ( 3 ), 1.32, and 1.49 mdyn/Å ( 4 ). Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved.     

Darstellung,Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von vier bindungsisomeren Tetrachlorodirhodanoosmaten(IV)

Preparation, Crystal Structures, Vibrational Spectra, and Normal Coordinate Analysis of Four Linkage Isomeric Tetrachlorodirhodanoosmates(IV) By treatment of cis- or trans-[OsCl₄I₂]^2? with (SCN)₂ in dichloromethane the linkage isomers cis-[OsCl₄(NCS)₂]^2? ( 1 ), trans-[OsCl₄(NCS)(SCN)]^2? ( 2 ), cis-[OsCl₄(NCS)(SCN)]^2? ( 3 ) and trans-[OsCl₄(SCN)₂]^2? ( 4 ) are formed which have been separated by ion exchange chromatography on diethylaminoethyl cellulose. The X-Ray structure determinations on single crystals of cis-(Ph₄As)₂[OsCl₄(NCS)₂] (triclinic, space group P1 , a = 10.019(5), b = 11.702(5), c = 21.922(5) Å, α = 83.602(5)°, β = 85.718(5)°, γ = 73.300(5)°, Z = 2), trans-(Ph₄As)₂[OsCl₄ · (NCS)(SCN)] (monoclinic, space group P2₁/c, a = 18.025(5), b = 11.445(5), c = 23.437(5) Å, β = 94.208(5)°, Z = 4), cis-(Ph₄As)₂[OsCl₄(NCS)(SCN)] (triclinic, space group P1 , a = 10.579(5), b = 11.682(5), c = 22.557(5) Å, α = 81.073(5)°, β = 85.807(5)°, γ = 87.677(5)°, Z = 2) and trans-(Ph₄As)₂ · [OsCl₄(SCN)₂] (triclinic, space group P1 , a = 10.615(5), b = 11.691(5), c = 11.907(5) Å, α = 111.314(5)°, β = 96.718(5)°, γ = 91.446(5)°, Z = 1) reveal the complete ordering of the complex anions. The via N or S coordinated thiocyanate groups are located nearly direct above one of the cis-positioned Cl ligands with Os? N? C angles of 171.2° and 174.3° ( 1 ), 162.3° ( 2 ), 172° ( 3 ) and Os? S? C angles of 108.3° ( 2 ), 105.7° ( 3 ) and 105.5° ( 4 ). Using the molecular parameters of the X-Ray determinations the low temperature (10 K) IR and Raman spectra of the (n-Bu₄N) salts of all four linkage isomers are assigned by normal coordinate analyses based on a modified valence force field. The valence force constants are f_d(OsN) = 1.59 ( 1 ), 1.67 ( 2 ), 1.60 ( 3 ) and f_d(OsS) = 1.27 ( 2 ), 1.31 ( 3 ) and 1.32 mdyn Å^?1 ( 4 ). Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved.     

Comparative Thermogravimetric Studies of Poly(ether-ketone/sulfone) Imides and Their Parent Polymers: I. Poly(ether-ketone/sulfone) ethylimide

Thermogravimetry (TG) was employed to study the thermal degradation kinetics of poly(etherketone/sulfone)ethylimide (PEK-IE and PES-IE). The corresponding decomposition activation energies and reaction orders were obtained and the comparison was made with their parent polymerspoly(ether-ketone/sulfone) with Cardo group (PEK-C and PES-C). The results show that the degradation activation energies of PEK-IE and PES-IE were lower than that of PEK-C and PES-C; and two stages of the degradation process were found for all the four polymers. For PEK-IE and PES-IE, the activation energies in the first decomposition stage are much lower than that in the second stage and the two stages can be taken as slow induction and fast degradation, whereas for PEK-C and PES-C the activation energies in the first decomposition stage are larger than that in the second stage, and the two stages can both be taken as two fast degradation stages. The decomposition mechanism of the two stages was also speculated.This revised version was published online in November 2005 with corrections to the Cover Date.     

Darstellung und Kristallstruktur von (n-Bu4N)3[Ir(NCS)(SCN)5]

Preparation and Crystal Structure of (n-Bu₄N)₃[Ir(NCS)(SCN)₅] The evaporated ethanolic extrakt of the reaction product of K₃[IrCl₆] and HNO₃, refluxed with an aqueous KSCN solution yields a mixture of the linkage isomers [Ir(NCS)_n(SCN)_6?-n]^3?, n = 0? 2, and small amounts of linkage isomeric chloropentarhodanoiridates(III), from which [Ir(NCS)(SCN)₅]^3? has been isolated by ion exchange chromatography on DEAE-cellulose. The X-Ray structure determination on a single crystal of (n-Bu₄N)₃[Ir(NCS)(SCN)₅] (monoclinic, space group P 2₁/a, a = 17.513(5), b = 32.607(5), c = 23.661(5) Å, β = 94.757(5)°, Z = 8) confirms the existance of a heteroleptic hexakis(thiocyanato(N)-thiocyanato(S))iridate(III) with an Ir? N distance of 2.03 Å and Ir? S bond lengths between 2.29 and 2.38 Å. The SCN groups with angles between 166 and 175° are nearly linear with Ir? S? C angles from 99.9 to 109.4°. The Ir? N? C angles of the two crystallographic independent anions are 166 and 174°.     

SYNTHESIS AND CHARACTERIZATION OF METAL COMPLEXES WITH AMPICILLIN

Abstract

The reaction, in water, of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions with sodium ampicillinate at room temperature has allowed isolation of dimers with the following general formula [M(amp)Cl]₂ × nH₂O (n = 1.5?3.2). The complexes were characterized by elemental analyses, conductivity measurements, magnetic susceptibilities and spectroscopic methods (IR, Raman, EPR and UV-Visible). A dinuclear structure based on octahedrally coordinated metal ions is proposed.     

PMDA-BPDA-HAB聚苯并噁唑的合成及耐热性

PMDA-BPDA-HAB聚苯并噁唑的合成及耐热性;均苯四甲酸二酐;联苯四羧酸二酐;二羟基联苯胺;聚酰亚胺;聚苯并噁唑;耐热性     

Thermal Degradation of Poly(ε-caprolactone), Poly(L-lactic acid) and their Blends with Poly(3-hydroxy-butyrate) Studied by TGA/FT-IR Spectroscopy

Summary: The thermal degradation behavior of poly(ε-caprolactone) (PCL) and poly(L-lactic acid) (PLA) have been studied in different environment. It was found that these polymers undergo completely different degradation processes in nitrogen and oxygen atmosphere. In oxygen environment PCL and PLA mainly decompose to CO₂, CO, water and short-chain acids. In nitrogen atmosphere PCL releases 5-hexenioc acid, CO₂, CO and ε-caprolactone, whereas PLA decomposes to acetaldehyde, CO₂, CO and lactide. The polymer blends of poly(3-hydroxybutyrate) (PHB) with PCL and PLA decompose similar to the individual homopolymers with crotonic acid as the initial decomposition product of PHB.     

Energy relationship and the polarization of C_(60) cage in the endohedral complexes (X@C_(60))

In this paper, we carry out the calculation on the system (X@C60)(X=Li, Na, K, Kb, Cs; F, Cl, Br, I), where the position of X changes along 5 typical symmetry directions. For the calculation of quantum chemistry we use EHMO/ASED method, for the calculation of molecular mechanics we use Buckingham potential (exp-6-1) function, and for the calculation of thermo-chemical cycle we use individually isolating the processes such as the structure variation, charge transfer and charge distribution, and their interactions etc. The calculation results show that (1) In the region of radius r≈0.2 nm of the Ceo cage, the potential field is nearly spherical; (2) Except for Li and Na, the systems are the most stable with minimum energies at the center of C60 cage. For Li and Na, the systems are the most stable with minimum energies at r≈0.16 nm and r≈0.13 nm, respectively. In view of the interactive region of chemical bonds, the interactions between X and the C60 cage do not belong to the classical chemical bonds; (     

铜在3%NaCl溶液中腐蚀行为的光电化学研究

Cu以其优异的导电性、导热性和易加工性广泛用于工农业生产中．自然Cu的腐蚀和防腐成为人们很关注的问题．人们已经注意到，Cl-对Cu的腐蚀有影响，并进行过一些研究．但目前使用光电化学方法研究这一问题的文章尚不多见，特别是利用测量开路光电压及其瞬态波形这一现场的、无损的、灵敏的监测方法研究户对Cu电极腐蚀全过程的文章尚未见到．本文正是利用如上方法及XPS，AES方法，研究了Cl-对Cu电极腐蚀的全过程，取得了一些有意义的结果．1实验方法Cu电极用99．99％（质量分数）的Cu制成，面积约为39mm2；电极底部由Cu导线焊接引出，…     

On the morphological behavior of ABC miktoarm stars containing poly(cis 1,4-isoprene), poly(styrene), and poly(2-vinylpyridine)

Fundamental understanding of microphase separation in ABC miktoarm copolymers is vital to access a plethora of nonconventional morphologies. Miktoarm stars based on poly(cis 1,4-isoprene) (I), poly(styrene) (S), and poly(2-vinylpyridine) (V) are model systems, which allow systematic studies of the effects of composition, chemical microstructure, and temperature on the thermodynamics of microphase separation. Eleven ISV-x (I:S:V = 1:1:x, v:v:v) miktoarm copolymers were synthesized by anionic polymerization affording well-defined copolymers with a variable V arm. Equilibrium bulk morphologies of all samples, as evidenced by small-angle X-ray scattering, transmission electron microscopy (TEM), and self-consistent field theory, showed a systematic transition from lamellae (x ≈ 0–0.2) to [8.8.4] tiling (x ≈ 0.6–0.9) to cylinders in undulating lamellae (x ≈ 2–4) and, finally, to hexagonally packed core–shell cylinders (x ≈ 5–8). Chemical microstructure of the I arm [poly(cis 1,4-isoprene)] versus poly(3,4-isoprene) is shown to play important role in affecting morphological behavior. To reconcile differences between ISV-x star morphologies reported in the literature and those reported herein, even for the same composition, effects of the microstructure of I arm on the Flory–Huggins parameter between I and V arms were taken into account in a qualitative manner. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 1491–1504