液相色谱–质谱法测定血清中左乙拉西坦含量

建立测定血清中左乙拉西坦浓度的液相色谱–质谱方法。血清样品用甲醇提取,离心分离除去蛋白,采用液相色谱–质谱法测定其中左乙拉西坦的含量。流动相为甲醇–0.1%甲酸(体积比为80∶20),色谱柱为Agilent C18柱(100 mm×4.6 mm,3.5μm)。左乙拉西坦含量在1 000~100 000 ng/m L范围内与色谱峰面积线性关系良好,线性相关系数r2=0.999,检出限为10 ng/m L。测定结果的相对标准偏差为0.93%(n=6),样品加标回收率为99.4%~101.3%。该方法具有较高的灵敏度、准确度和良好的精密度,适合血清中左乙拉西坦含量的测定。     

超高效液相色谱–串联质谱法检测果蔬中的吡氟甲禾灵残留

建立了超高效液相色谱–串联质谱(UPLC–MS/MS)法测定果蔬中吡氟甲禾灵残留的方法。样品以乙腈匀浆提取,并采用Sep-Pak Vac型氨基固相萃取柱净化样品,采用超高效液相色谱柱WATERS ACQUITY C_(18)柱(50mm×2.1 mm,1.7μm)分离,以乙腈–0.1%甲酸水溶液作为淋洗液进行梯度洗脱。吡氟甲禾灵在1.0~50.0 ng/m L范围内线性关系良好,相关系数r~2=0.997 7,加标回收率为84.1%~88.6%,测定结果的相对标准偏差为1.18%~3.58%(n=6)。该方法操作简便,分析快速,提取效率高,重现性好,有实用价值。     

亲水超高效液相色谱–串联质谱法同时测定尿液中百草枯和敌草快

建立亲水超高效液相色谱–串联质谱法同时测定尿液中百草枯和敌草快的方法.样品经磷酸盐缓冲液(pH=6.8)提取,用弱阳离子交换固相萃取柱净化,选择Waters HILIC色谱柱(100 mm×2.1 mm,1.7μm)为分离柱,以乙腈–200 mmol/L甲酸铵水溶液(pH=3.7)为流动相,梯度洗脱,采用多反应监测(M...     

柱后衍生HPLC法测定功能饮料中的牛磺酸

建立柱后衍生–高效液相色谱法测定功能性饮料中牛磺酸的含量。功能性饮料中的牛磺酸经水溶提取后与邻苯二甲醛柱后衍生,以柠檬酸三钠溶液(p H 3.2)为流动相,用AMINO–NA色谱柱分离,荧光检测器检测,激发波长为338 nm,发射波长为425 nm,柱后衍生反应温度为55℃,流量为0.4 m L/min。牛磺酸质量浓度在5.0~25.0μg/m L范围内与色谱峰面积线性关系良好,r=0.999 8,检出限(S/N=3)为0.11μg/m L,测定结果的相对标准偏差为0.73%(n=6),加标回收率在99.2%~101.6%之间。该方法灵敏度高、选择性好,可用于市售功能性饮料中牛磺酸的测定。     

高效液相色谱法测定葛根芩连片中的葛根素

建立高效液相色谱测定葛根芩连片中葛根素含量的方法。以体积分数50%的甲醇为提取液对样品超声提取20 min,采用DiamonsilTMC18(250 mm×4.6 mm,5μm)色谱柱,以甲醇–乙腈–水(体积比8∶12∶80)为流动相,流速为1.0 mL/min,检测波长为250 nm,柱温为30.0℃,进样量体积10μL。在最佳实验条件下,葛根素与其它物质能完全分离,葛根素的质量浓度在5.43~543.2μg/mL范围内与色谱峰面积呈良好的线性,线性相关系数r=0.999 9,方法检出限为3.50μg/mL(S/N=3)。方法加标回收率为100.0%,测定结果的相对标准偏差为1.6%(n=6)。该方法简单、快速、重现性好,适用于葛根芩连片中葛根素的测定。     

蒸发光散射高效液相色谱法测定黄芪饮片中的黄芪甲苷含量

采用蒸发光散射高效液相色谱法测定黄芪饮片中黄芪甲苷的含量。黄芪饮片分别用甲醇和正丁醇提取,以Na OH溶液洗涤,蒸干,再用甲醇溶解,采用Agilent SB–C18柱(250 mm×4.6 mm,5μm)分离测定,流动相为乙腈–水(32∶68),流量为1.0 m L/min,漂移管温度为80℃。方法检出限为1.5μg/m L,黄芪甲苷溶液的质量浓度在2~12μg/m L范围内与色谱峰面积线性关系良好(r2=0.999 6),测定结果的相对标准偏差为0.65%(n=6),平均加标回收率为99.6%。该方法稳定可靠,可用于黄芪药材及其生物制品中黄芪甲苷含量的测定。     

凝胶排阻色谱法测定中空纤维超滤膜组件对聚乙二醇的截留率

采用凝胶排阻色谱法测定中空纤维超滤膜组件对聚乙二醇20000(PEG20000)溶液的截留率,选择Agilent PL aquagel-OH MIEXD–H8μm色谱柱,流动相为0.1 mol/L Na NO3溶液(含0.02%Na N3),流量为1 m L/min,RID检测器,柱温箱和检测器温度均为30℃。当进样体积为50μL时,方法的检出限为18.8 mg/L,定量限为49.0 mg/L。PEG20000溶液的质量浓度在60~1 000 mg/L范围内与色谱峰高呈良好的线性,相关系数r2=1.000。该方法对实际样品测定结果的相对标准差为1.31%(n=6)。将该方法的测定结果与紫外–可见分光光度计法的测量结果进行F检验和t检验,结果表明两种方法测量结果无显著性差异。采用该方法可以同时对PEG20000样品的相对分子质量及其分布进行测定,从而对选用的截留标准物质进行质量控制。     

HPLC法测定土圞儿根皮和块根中的西瑞香素

建立高效液相色谱法测定土圞儿根皮和块根中西瑞香素含量的方法。采用Kromasil C18色谱柱(250mm×4.6 mm,5μm),以甲醇–0.2%磷酸水溶液(56∶44)为流动相等度洗脱,流量为1.0 m L/min,柱温为35℃,检测波长为345 nm。西瑞香素的质量浓度在20~100μg/m L内与色谱峰面积呈现良好的线性关系,线性相关系数r=0.999 9,方法精密度(RSD)为1.23%(n=6)。根皮样品、块根样品的加标回收率分别为98.8%,98.2%,测定结果的相对标准偏差分别为1.30%,2%(n=6)。该方法快速可靠,可用于土圞儿药材的质量控制。     

HPLC法快速测定熟肉制品中10种食品添加剂

建立了熟肉制品中10种食品添加剂的高效液相色谱分析方法。以乙醇–氨水溶液为提取溶剂,样品经超声波辅助溶剂萃取法萃取后,以Atlantis d C18(250 mm×4.6 mm,5μm)色谱柱为分离柱,20 mmol/L乙酸铵–甲醇为流动相进行分离测定。10种目标化合物的质量浓度在1.0~200.0 mg/L范围内与其峰面积线性关系良好(r0.999),在20.0,500.0,1 000.0 mg/kg的添加水平下,10种目标化合物的平均加标回收率为82%~104%,测定结果的相对标准偏差小于4.0%(n=6),方法的检出限为1.0~5.0 mg/kg(S/N=3)。该方法简单、快速、准确,适合于熟肉制品中食品添加剂的检测。     

反相高效液相色谱法测定消毒凝胶中的度米芬

建立高效液相色谱测定消毒凝胶中度米芬含量的方法。样品经Shim-Pack VP–ODS C_(18)柱(250 mm×4.6mm,5μm)分离,以0.012 mol/L十二烷基硫酸钠–乙腈–甲醇(2∶6∶2)为流动相,流量为1.5 mL/min。用紫外检测器检测,检测波长为269 nm。度米芬的质量浓度在0～434.20μg/mL范围内与色谱峰面积呈良好的线性关系,线性相关系数为1,方法检出限为0.13μg/mL。平行测定结果的相对标准偏差为1.13%(n=6),平均加标回收率为97.80%。该方法灵敏度高,重现性好,通用性强,可作为消毒产品中度米芬含量测定的检测方法。     

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。     

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.     

Acid hydrolysis of carboxymethylcellulose of low degree of substitution

Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.     

Estimation of Kinetic Parameters of Thermal Oxidation of Ilmenite

The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe₂O₃. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.     

Mechanism of action of base-catalyzed oxygenation of phenol derivatives

Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

化学计量中不确定度评定研究进展

测量不确定度是表征合理地赋予被测量之值的分散性的参数。本文针对化学计量不确定度评定基础模型仅适用于线性模型、概率分布为正态分布或缩放位移t分布等局限,介绍了近年来不确定度评定的研究热点:蒙特卡罗方法(Monte Carlo Method,MCM),不确定度评定的来源、评定概念、评估方法及其发展过程,扩大了测量不确定度评定与表示的适用范围。     

微量钙的测定方法研究进展

介绍了1995-2006年期间测定微量和痕量钙的方法,如电感耦合等离子体-原子发射光谱法、原子吸收光谱法以及离子色谱法等的工作原理和特点,并说明了其测定微量钙的应用领域。并对微量钙的测定技术进行了展望(引用文献55篇)。     

Stages of thermal decomposition of sodium oxo-salts of sulphur

Thermal behaviour of sodium oxo-salts of sulphur: Na₂SO₄, Na₂S₂O₇, Na₂S₂O₆, Na₂SO₃, Na₂S₂O₅, Na₂S₂O₄, Na₂S₂O₃, Na₂S₃O₆ and of sulphides Na₂S and Na₂S₂ was studied on heating up to 1000°C. The experiments were performed with anhydrous compounds obtained from commercial products by recrystallisation and dehydration. The stage mechanisms of decomposition of anionic sub-lattices of the salts have been proposed basing on the Górski’s morphological classification of simple species. The thermal stability and the stage decomposition mechanisms were correlated with the structure and the potential chemical properties of the salt anions. The thermal decomposition processes were studied by means of thermal analysis, and the decomposition products were identified by means of X-ray phase analysis.     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.