高效液相色谱-串联质谱法同时测定食品接触材料中间苯二酚-o,o’-二乙酸、2-羟基-6-萘甲酸、间苯二甲酸二甲酯-5-磺酸钠的特定迁移量

建立了高效液相色谱-串联质谱(HPLC-MS/MS)法同时测定食品模拟物(10%乙醇、3%乙酸、20%乙醇、50%乙醇和橄榄油)中间苯二酚-o,o’-二乙酸、2-羟基-6-萘甲酸、间苯二甲酸二甲酯-5-磺酸钠的特定迁移量(SM)。水基食品模拟物样品经亲水性聚四氟乙烯针式过滤器过滤后进样;橄榄油食品模拟物样品用0.1%乙酸铵溶液震荡提取12 min后,静置15 min,下清液用亲水性聚四氟乙烯针式过滤器过滤后进样。用C8柱梯度洗脱分离;Qtrap4500质谱在电喷雾离子源负离子及多反应监测(M RM)模式下进行检测。方法在5种食品模拟物中的定量限为0.3~1.2μg/kg;水基食品模拟物在10~200μg/L、橄榄油食品模拟物在10~200μg/kg范围内线性关系良好(r0.99904);加标回收率为86.0%~116%,相对标准偏差为0.5%~7.2%。方法满足欧盟(EU)NO 10/2011法规附表1中间苯二酚-o,o’-二乙酸、2-羟基-6-萘甲酸、间苯二甲酸二甲酯-5-磺酸钠的SM限量要求。方法已应用于实际样品的检测。     

高效液相色谱-串联质谱法同时检测食品接触材料中9种抗氧剂的特定总迁移量

建立了高效液相色谱-串联质谱(HPLC-MS/MS)联用方法同时测定塑料制品食品模拟物(10%乙醇、20%乙醇、50%乙醇、3%乙酸和橄榄油)浸泡液中9种抗氧剂的特定总迁移量[SML(T)]。食品模拟物浸泡待测样品,冷却至室温并混匀,水基食品模拟物(10%乙醇、3%乙酸、20%乙醇、50%乙醇)用含0.05%三(2-羧乙基)膦盐酸盐(TCEP)60%的四氢呋喃水基食品模拟物溶液稀释5倍后,经亲水性聚四氟乙烯针头过滤器过滤后进样;橄榄油用甲醇正庚烷提取后,下清液用亲水性聚四氟乙烯针头过滤器过滤后进样。用C8柱梯度洗脱分离;质谱具电喷雾离子源,在负离子多反应监测(MRM)模式下运行;方法在5种食品模拟物中的定量限为0.01~0.3 mg/kg;水基食品模拟物在0.03~0.72 mg/L,0.06~1.44 mg/L,0.1~2.4 mg/L或0.3~7.2 mg/L,橄榄油食品模拟物在0.15~3.6 mg/kg,0.3~7.2 mg/kg,0.5~12.0 mg/kg或1.5~36 mg/kg范围内线性关系良好(R≥0.99240);0.3~21 mg/kg水平的加标回收率为74.4%~132%,相对标准偏差为0.8%~20%。方法满足欧盟(EU)NO 10/2011法规附表2中9种抗氧剂SML(T)的限量要求,并已应用于实际样品的检测。     

高效液相色谱-串联质谱法同时测定食品接触材料中七种苯多酸及其衍生物的特定总迁移量

建立了高效液相色谱-串联质谱(HPLC-MS/MS)联用方法同时测定食品模拟物(10%乙醇、20%乙醇、50%乙醇、3%乙酸和橄榄油)中偏苯三甲酸、偏苯三甲酸酐、间苯二甲酰氯、间苯二甲酸、对苯二甲酰氯、邻苯二甲酸、对苯二甲酸的特定总迁移量[SML(T)]。食品模拟物浸泡待测样品,冷却至室温并混匀,水基食品模拟物经亲水性聚四氟乙酸针头过滤器过滤后进样;橄榄油用0.1%乙酸铵溶液提取后,下清液用亲水性聚四氟乙酸针头过滤器过滤后进样。用Synergi Polar-RP柱等度洗脱分离;质谱具电喷雾离子源,在负离子多反应监测(MRM)模式下运行;方法在5种食品模拟物中的定量限为0.004~0.04 mg/kg;在0.5~12 mg/L范围内线性关系良好(r0.9975);1.25,2.5,6.25 mg/kg水平的加标回收率为91.2%~121%,相对标准偏差为0.6%~4.5%。该方法满足欧盟(EU)NO 10/2011法规附表2中7种苯多酸及其衍生物的SML(T)的限量要求,并已应用于实际样品的检测。     

高效液相色谱-紫外检测法同时测定食品接触材料中7种苯多酸及其衍生物的特定总迁移量

建立了高效液相色谱-紫外检测(HPLC-UV)同时测定5种食品模拟物(10%(v/v)乙醇、20%(v/v)乙醇、50%(v/v)乙醇、3%(w/v)乙酸和橄榄油)中偏苯三甲酸、偏苯三甲酸酐、间苯二甲酰氯、间苯二甲酸、对苯二甲酰氯、邻苯二甲酸、对苯二甲酸的特定总迁移量(SML(T))的方法。用食品模拟物浸泡待测样品,冷却至室温并混匀,水基食品模拟物经亲水性聚四氟乙酸针头过滤器过滤后进样;橄榄油用0.1%(w/v)乙酸铵水溶液提取后,下层清液用亲水性聚四氟乙烯针头过滤器过滤后进样。用Synergi Polar-RP色谱柱(250 mm×4.6 mm, 4 μm)分离,梯度洗脱,检测波长为232 nm。5种食品模拟物中的定量限为0.1~0.2 mg/kg;水基食品模拟物在0.5~12 mg/L、橄榄油食品模拟物在0.5~12 mg/kg范围内线性关系良好(r² > 0.99991); 1.25、2.5、6.25 mg/kg水平的加标回收率为94.3%~105%,相对标准偏差为0.1%~2.3%。结果表明,该方法的色谱分离和线性关系较好,回收率和准确度高,完全满足欧盟(EU)No 10/2011法规附表2中7种苯多酸及其衍生物的SML(T)的限量要求,并已应用于实际样品的检测。     

高效液相色谱-串联质谱法测定食品接触材料及制品中27种全氟化合物迁移量

建立了食品接触材料迁移模拟环境中27种全氟化合物的高效液相色谱-串联质谱检测方法。选取乙酸(3%)、乙醇(10%、50%)和橄榄油作为食品模拟物,模拟了食品接触材料在与不同类型食物接触下的迁移行为,根据(EU)No.10/2011的要求对样品进行处理,每6 dm2食品接触材料加入1 L食品模拟物浸泡。水相模拟物经过滤后直接检测,橄榄油经乙腈提取后进行检测。模拟溶液样品以甲醇-水混合溶液为流动相,经C18色谱柱分离,在MRM模式下进行检测。结果表明:全氟化合物在1~1 000μg/L质量浓度范围内线性关系良好(r0.999 1);全氟化合物在食物模拟物中的定量下限为0.28~9.85μg/kg;对空白样品进行10、100 ng两个浓度水平的加标回收试验,加标回收率为82.6%~112.1%,相对标准偏差为2.2%~7.2%。     

液相色谱-串联质谱法测定食品接触材料中5种乙醇胺类化合物的迁移量

建立了不同食品接触材料中5种乙醇胺类化合物迁移量的液相色谱-串联质谱(LC-MS/MS)测定方法。以5种不同食品模拟物(水、4%乙酸、10%乙醇、50%乙醇、95%乙醇)浸泡样品,4%乙酸浸泡液经氮气吹干后用水复溶,其他浸泡液直接过滤后进样。采用氨基柱BEH Amide(50 mm×2.1 mm,1.7μm)分离,以乙腈-5 mmol/L乙酸铵溶液为流动相,梯度洗脱分离,在电喷雾源的正离子多反应监测(MRM)模式下检测,外标法定量。在优化条件下,5种乙醇胺类化合物在1.0~750.0μg/L范围内线性关系良好,相关系数均大于0.997,检出限(LOD,S/N=3)和定量下限(LOQ,S/N=10)分别为0.3~5.0μg/kg和1.0~15.0μg/kg。在1.0~750.0μg/kg加标水平下的回收率为90.2%~118%,相对标准偏差(RSD)为0.5%~8.8%。该方法高效灵敏、准确可靠,可满足相关检测的需求。     

高效液相色谱-串联质谱法测定塑料类食品接触材料中4种苯胺衍生物的特定迁移量

采用高效液相色谱-串联质谱法同时测定间苯二甲胺、N-乙酰对氨基苯酚、4,4′-二氨基二苯砜、N,N′-二苯基硫脲在5种食品模拟物中的特定迁移量。水基模拟物样品过聚四氟乙烯(PTFE)过滤器后进样;油性(橄榄油)模拟物样品用20mmol·L~(-1)磷酸二氢钾溶液-甲醇(1+1)混合液振荡提取10min,提取液过PTFE过滤器后进样。采用C_(18)柱进行梯度洗脱分离,质谱分析中选择电喷雾离子源正离子及多反应监测模式。4种化合物的质量浓度在一定范围内与峰面积呈线性关系,测定下限(10S/N)在2.0~20μg·kg~(-1)之间。加标回收率在85.6%~108%之间,测定值的相对标准偏差(n=6)在0.90%~8.8%之间。用该方法检测实际样品,发现有N,N′-二苯基硫脲检出。     

有机相阴离子交换固相萃取HPLC-UV法快速测定食品接触材料中4种尼泊金酯的特定迁移量

建立了有机相阴离子交换固相萃取/高效液相色谱紫外法(HPLC-UV)快速测定10%乙醇、3%乙酸、20%乙醇、50%乙醇和橄榄油食品模拟物中尼泊金甲酯、尼泊金乙酯、尼泊金异丙酯和尼泊金丙酯的特定迁移量(SM)。橄榄油食品模拟物样品采用有机相阴离子交换固相萃取法净化,水基食品模拟物样品经亲水性聚四氟乙烯针式过滤器过滤后直接进样。以甲醇和纯水为流动相,4种尼泊金酯在ZORBAX SB-Phenyl柱上等度洗脱,12.5 min内达到基线分离;紫外外标校准曲线法定量。4种尼泊金酯在0.5~100 mg/L范围内线性关系良好(r2≥0.999 8),在10、50、100 mg/kg 3个浓度水平下的加标回收率为97.9%~103%,相对标准偏差为0.02%~2.2%,在5种食品模拟物中的定量下限为0.1~0.5 mg/kg。结果表明,该方法的色谱分离和线性关系好,回收率和准确度高,满足欧盟(EU)NO 10/2011法规附表1中4种尼泊金酯SM的限量要求,并已应用于实际样品的检测。     

顶空/气相色谱-质谱联用法测定食品接触材料中5-亚乙基-2-降冰片烯的迁移量

建立了顶空/气相色谱-质谱联用(HS/GC-MS)测定食品接触材料中5-亚乙基-2-降冰片烯(ENB)迁移量的方法,对前处理方法(溶剂提取-直接进样和气液平衡-顶空进样)、顶空平衡温度、顶空平衡时间进行了优化。以水、4%(体积分数)乙酸、50%(体积分数)乙醇和橄榄油作为食品模拟物,样品经食品模拟物浸泡,于顶空气液平衡后进样,经DB-5 MS色谱柱(30 m×0. 25 mm×0. 25μm)分离后,采用选择离子模式进行检测,外标法定量。在优化实验条件下,ENB在0. 1～10 mg/L范围内呈良好的线性关系,相关系数(r)大于0. 999,在0. 1、1. 0、10 mg/L 3个加标水平下,方法的回收率为92. 0%～108%,相对标准偏差(RSD,n=5)为0. 9%～4. 0%,检出限(LOD)为0. 01 mg/kg,定量下限(LOQ)为0. 03 mg/kg。该方法准确、可靠、灵敏度高,适用于食品接触材料中ENB迁移量的测定。     

高效液相色谱–串联质谱法同时测定塑料食品接触材料中20种邻苯二甲酸酯迁移量

采用高效液相色谱–串联质谱(LC–MS/MS)技术建立了食品接触材料中20种邻苯二甲酸酯类迁移量的测定方法。样品分别采用欧盟(EU)No.10/2011法规中食品模拟液浸泡,橄榄油浸泡液用乙腈进行液–液萃取,水基浸泡液直接过滤,C18色谱柱(100 mm×2.1 mm,2.7μm)分离,以0.1%甲酸溶液–甲醇溶液为流动相,梯度洗脱,采用多反应监控(MRM)模式进行分析检测。20种邻苯二甲酸酯类化合物质量浓度在1~500 ng/m L范围内与色谱峰面积呈线性关系。水溶液、3%乙酸食品模拟浸泡液、10%乙醇食品模拟浸泡液、20%乙醇食品模拟浸泡液、50%乙醇食品模拟浸泡液、橄榄油食品模拟浸泡液中方法定量限分别为0.20~9.81 ng/m L,0.19~9.76 ng/m L,0.25~12.3ng/m L,0.21~10.8 ng/m L,0.19~11.7 ng/m L,0.45~20.3 ng/m L。样品加标回收率为85.8%~111.3%(3%乙酸浸泡液),79.4%~123.6%(橄榄油浸泡液),两种浸泡液中测定结果的相对标准偏差不大于8.48%(n=6)。该方法具有快速简便、灵敏度高及准确性好等特点,适用于塑料类食品接触材料中邻苯二甲酸酯类迁移量的检测。     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。