阻抑溴酸钾氧化茜素红褪色动力学光度法测定药物中水杨酸

在稀盐酸介质中,水杨酸的存在对溴酸钾氧化茜素红褪色反应有很强的阻抑作用,利用光度法监测反应过程中茜素红浓度的变化,建立了水杨酸-溴酸钾-茜素红体系阻抑动力学光度法测定水杨酸含量的方法。在选定条件下,方法的线性范围是0.008μg·m L~(-1)-1.2μg·m L~(-1),检出限为0.0017μg·m L~(-1)。     

流动注射不可逆双安培法测定水杨酸的研究

基于不可逆电对的双安培检测原理,利用水杨酸在铂电极上的氧化和高锰酸钾在另一铂电极上的还原构建双安培检测新体系,建立了在外加电压为-0·3V条件下流动注射双安培法直接测定乙酰水杨酸片剂中微量水杨酸的新方法。结果在-0·3V外加电压下,0·05mol/L硫酸载液中,测得水杨酸的响应电流与其浓度在8·00×10-6~4·00×10-4mol/L范围内呈线性关系(r=0·9985,n=7),检出限为2·00×10-6mol/L,连续测定1·00×10-4mol/L的水杨酸溶液13次,电流值RSD为2·36%,进样频率为80样/h。该方法具有较高的选择性和灵敏度,样品处理方法简单快速,适于在线分析。     

高效液相色谱法测定防晒化妆品中水杨酸酯类紫外线吸收剂的含量

采用高效液相色谱法同时测定防晒化妆品中8种水杨酸酯类紫外线吸收剂(水杨酸乙基己酯、水杨酸三甲环己酯、水杨酸辛酯、水杨酸苯酯、水杨酸异十六酯、水杨酸己酯、水杨酸乙二醇酯和水杨酸苄酯)的含量。1.000 0g样品经5mL乙酸乙酯于20℃超声萃取10min,萃取液在Agilent ZORBAX Eclipse XDB-C_(18)色谱柱上分离,以甲醇-四氢呋喃-0.1%(质量分数)甲酸溶液为流动相进行梯度洗脱,紫外检测波长为340nm。8种水杨酸酯类紫外线吸收剂质量浓度在5.0~100.0mg·L~(-1)内与峰面积呈线性关系,检出限(3S/N)在0.5~2.5mg·kg~(-1)之间;加标回收率在90.6%~98.8%之间,测定值的相对标准偏差(n=6)在1.4%~3.6%之间。     

库仑滴定法测定己内酰胺与聚醚样品中过氧化物的含量

建立了库仑滴定法测定己内酰胺与聚醚样品中过氧化物含量的方法。铂片电极分别作电解电极对和指示电极对,以1.00 mol·L~(-1)氯化铈溶液为支持电解质,经1.0 mA电流电解生成Ce~(4+)后,与样品溶液中过氧化物定量发生氧化还原反应,根据法拉第电解定律,计算样品中过氧化物的含量。结果表明:标准曲线的线性范围为24.11～301.35 mg·L~(-1),检出限(3s)为7.2μg·g~(-1)。采用该方法分析实际样品,测定结果与电位滴定法的结果无显著性差异,测定值的相对标准偏差(n=5)均低于3.0%。     

纳氏光度法现场快速测定环境水中的氨氮

研究在纳氏试剂光度法(GB7479-1987)的基础上,利用便携式分光光度计进行环境水质样品中氨氮含量的现场快速测定。氨氮浓度在0.00~2.00mg/L与吸光度呈良好的线性关系,线性相关系数r=0.9998,检出限为0.04mg/L,样品的加标回收率为90%~106%,测定结果的相对标准偏差为1.21%~4.27%(n=6)。该方法的测定结果与标准法测定结果无显著性差异,可以用于现场快速测定水和废水中的氨氮。     

气相分子吸收光谱法在地表水氨氮监测中的应用北大核心CSCD

气相分子吸收光谱法测定环境地表水中氨氮含量的标准方法研究还不全面,因此考察了水样的保存、亚硝酸盐、Ca^(2+)、Mg^(2+)、I^(-)、硫化物对其测定结果的影响.结果表明,采集地表水样后立即加入硫酸使水样酸化至pH<2,密闭,可延长样品保存时间至7 d,但尽量在24 h内进行测定;气相分子吸收光谱法测定氨氮水样时,当亚硝酸盐含量较高时,在氨氮除亚氮功能模式下已不能消除干扰,必须在水样分析前采用加热煮沸或预蒸馏前处理方式;水中Ca^(2+)、Mg^(2+)、25倍以下质量浓度的I^(-)和10倍质量浓度以下的硫化物对气相分子吸收光谱法氨氮测定没有显著干扰.本方法的检出限(3.143s)为0.02 mg·L^(-1),按标准加入法进行回收试验,回收率为94.7%~101%,测定值的相对标准偏差(n=6)为0.70%~4.7%.采用气相分子吸收光谱法分析标准样品,其测定结果均在标准样品认定值的允许偏差范围内.与纳氏试剂分光光度法的测定结果相比,预蒸馏-气相分子吸收光谱法具有更好的精密度和准确度.     

密闭消解-氢化物发生-原子荧光光谱法测定植物中硒

采用密闭消解-氢化物发生-原子荧光光谱法测定植物中硒的含量。植物样品采用硝酸-过氧化氢(2+1)混合液于130℃密闭消解4h,以10g·L~(-1)硼氢化钠溶液作为还原剂。硒的质量浓度在2~10μg·L~(-1)内与其对应的荧光强度呈线性关系,检出限(3s/k)为0.18μg·L~(-1)。对10μg·L~(-1)的硒标准溶液连续测定6次,测定值的相对标准偏差为0.63%。以圆白菜标准物质(GBW 10014)为基体进行加标回收试验,所得回收率为102%。     

高效液相色谱法测定食品添加剂中水杨酸

提出了高效液相色谱法测定食品添加剂中水杨酸含量的方法。样品采用含0.1%(体积分数)甲酸的甲醇-水(9+1)混合溶剂溶解,超声提取后经0.22μm滤膜过滤,滤液供高效液相色谱荧光仪测定。采用ZORBAX SB-C18色谱柱(4.6mm×250mm,3.5μm)分离,用不同配比的(A)甲酸-乙腈(0.1+99.9)和(B)甲酸-水(0.1+99.9)的混合溶液为流动相梯度洗脱,在激发波长为290nm、发射波长为400nm处检测。水杨酸的质量浓度在41.60～1 664μg·L-1范围内与其对应的峰面积呈线性关系,检出限(3S/N)为1.55μg·L-1,方法的回收率在90.4%～101.7%。     

连续流动注射分光光度法测定杏仁中氰化物和挥发酚的含量北大核心CSCD

提出了连续流动注射分光光度法同时测定杏仁中氰化物和挥发酚含量的方法。2.00 g杏仁样品经25 mL 0.05 mol·L^(-1)硫酸溶液涡旋1 min,浸泡10 min,水解释放样品中氰苷后,用2 g·L^(-1)氢氧化钠溶液固定待测物,并定容至50 mL。取上清液,经0.45μm滤膜过滤,滤液在优化的试验条件下采用连续流动注射分光光度法测定其中氰化物和挥发酚的含量。结果表明,氰化物和挥发酚的质量浓度在0.002~0.200 mg·L^(-1)内与对应的峰高呈线性关系,检出限分别为0.005 mg·kg^(-1)和0.0175 mg·kg^(-1)。取3份样品,每个样品重复测定6次,测定值的相对标准偏差(n=6)均小于2.0%。按照标准加入法对实际样品进行回收试验,回收率为97.6%~105%。方法用于分析10份杏仁样品,氰化物的检出量为10.6~56.4 mg·kg^(-1),平均值为32.3 mg·kg^(-1),挥发酚的检出量为14.7~54.8 mg·kg^(-1),平均值为31.9 mg·kg^(-1)。方法利用硫酸溶液水解样品中氰苷后用碱溶液固定,解决了碱溶液直接提取结果偏低的问题。     

化学衍生显色法间接测定乙酰水杨酸的含量

建立了以氯化铁测定阿司匹林中乙酰水杨酸的分光光度法。在盐酸溶液中,乙酰水杨酸的降解产物水杨酸能与氯化铁反应生成紫红色络合物,其最大吸收波长为526 nm,络合比为1:1。根据反应生成物的吸光度,可以间接测定乙酰水杨酸的含量。水杨酸的浓度在1.6~104.0 mg/L范围内与体系的吸光度呈良好的线性关系,线性回归方程A=0.01896+0.00952ρ(mg/L),相关系数r=0.9991,检出限为0.28 mg/L,相对标准偏差(RSD)为0.24%,表观摩尔吸光系数ε=1.78×103L·mol-1·cm-1。此法可用于药物制剂阿司匹林中乙酰水杨酸含量的测定。     

电堆集富集非水毛细管电泳同时测定水杨酸、肉桂酸、阿魏酸和香草酸

建立了同时分离测定水杨酸、肉桂酸、阿魏酸和香草酸的电堆集富集-非水毛细管电泳(NACE)的新方法。运行缓冲溶液为40mmol/L乙酸钠-2.5mmol/L氢氧化钠甲醇溶液,电压-25kV,在225nm波长下紫外检测。对电压、乙酸钠浓度、氢氧化钠浓度、进样时间、样品溶液等因素对电堆集及分离的影响做了系统的研究。水杨酸、肉桂酸、阿魏酸和香草酸分别在1.4~28mg/L、0.40~8.0mg/L、0.7~18mg/L和0.7~30mg/L范围内线性关系良好(r=0.9999、r=0.9997、r=0.9994、r=0.9997);回收率分别为95.8~99.6%、96.2~98·2%、95.7~105%和98.9~103%,基于3倍信噪比(S/N=3),4种有机酸的检出限分别为0.069、0.051、0.107和0.089mg/L。     

离子色谱法测定乙醛酸中的顺丁烯二酸和乙二酸

采用抑制电导离子色谱法测定高浓度乙醛酸基体中痕量的顺丁烯二酸和乙二酸。将乙醛酸样品稀释至1 000倍体积后,采用高浓度的淋洗液,以高容量色谱柱对样品进行分析。实验结果表明,顺丁烯二酸和乙二酸最低检出限分别为12.7,19.6μg/L,重现性(n=5)分别为1.13%,1.11%,回收率分别为97.9%,94.7%。该方法具有较高的灵敏度,适用于乙醛酸的例行检测。     

Determination of Cyanuric Acid or Trichloroisocyanuric Acid in Air

Abstract

An analytical procedure for measurement of cyanuric acid or trichlor oisocyanuric acid in air has been developed. The procedure involves air sampling with a 37-mm PVC membrane filter, recovery with a phosphate buffer, and analysis by high performance liquid chromatography with a UV detector at 225 nm. The interior surface of the front piece of the cassette filter holder also is analyzed. Average recoveries were 0.98 to 1.00 after fortification of PVC filters with 12- to 412-μg quantities of cyanuric acid. Average recoveries of trichloroisocyanuric acid were 0.83 to 0.98 after fortification of glass surfaces with 12- to 424-μg quantities (these are reasonable approximations for recoveries of trichloroisocyanuric acid from PVC filters). The analyst should ascertain which analyte is present at the sampling site because trichloroisocyanuric acid reacts with water in the phosphate buffer to form cyanuric acid in high yield.     

对氨基苯甲酸的合成研究进展

综述了以对硝基苯甲酸为原料合成对氨基苯甲酸的近期研究进展。并从技术和经济角度讨论了各种合成方法的优点与不足。     

以对甲基苯磺酸作为淋洗液用离子色谱法测定酸雨中的有机酸

本文研究了用对甲基苯磺酸作为淋洗液测定液相中HCOO~-和CH_3COO~-的离子色谱条件,该方法对HCOO~-和CH_3COO~-的最低检出限分别为48ppb和93ppb。该方法与用进口的辛磺酸作为淋洗液的方法进行了对比实验,并用于两广实际酸雨样品中甲酸和乙酸的测量。     

Surface Functionalization of Magnetite Nanoparticles with Sulfonic Acid and Heteropoly Acid: Efficient Magnetically Recoverable Solid Acid Catalysts

New magnetically recoverable solid acid catalysts for acid‐catalyzed reactions were designed via the surface chemical functionalization of silica‐coated magnetite nanoparticles (SCMNPs) with sulfonic acid groups. First, the SCMNPs were covalently functionalized with 3‐aminopropyl groups to achieve Amp‐SCMNPs. Then, reaction of the Amp‐SCMNPs with 1,4‐butane sultone followed by acidification with phosphotungstic acid (HPW) or diluted sulfuric acid produced magnetically recoverable solid acid catalysts, HPW‐ampsul‐SCMNPs and H‐ampsul‐SCMNPs, respectively. Both catalysts were characterized by various physicochemical analyses such as Fourier transform infrared (FT‐IR) and inductively coupled plasma‐optical emission (ICP‐OES) spectroscopies, vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), and energy‐dispersive X‐ray (EDX) analyses. Finally, the catalytic activities of the prepared catalysts were examined in the esterification of acetic acid with butanol and acetalization of benzaldehyde with ethylene glycol. Excellent catalytic efficiencies were obtained in both cases. The catalysts were consecutively recovered and reused five times without significant loss of their activities.     

Mechanochemical Complexation between Deoxycholic Acid and Salicylic Acid

A complex between deoxycholic acid (DCA) and salicylic acid (SA) was prepared by grinding and coprecipitation methods. The resultant complex was characterized by means of powder X-ray diffractometry, IR spectroscopy and thermal analysis. The stoichiometry (DCA : SA 1 : 1) of the complex obtained by grinding was identical to that obtained by coprecipitation. The powder X-ray diffraction pattern of the DCA–SA complex differed from the typical pattern of DCA–guest complexes such as DCA–camphor and DCA–phenanthrene complexes. IR spectra suggested that a different kind of hydrogen bonding was formed in the crystal of the DCA–SA complex, compared with the other DCA–guest complexes. This was in good agreement with data from the crystal structure.     

硝酸氧解法提高泥炭中黄腐酸的产率

硝酸氧解法提高泥炭中黄腐酸的产率;腐植酸;硝酸氧化降解     

Determination of Monochloroacetic Acid and Dichloroacetic Acid for Quality Control of Acetic Acid Chlorination Industry by Ion Chromatography

An ion chromatographic method is described for the purpose of quality control in the process of monochloroacetic acid production. Using 2.5 mM NaOH–10% methanol as eluent, the simultaneous determination of acetic acid, monochloroacetic acid, dichloroacetic acid, and Cl⁻ was obtained in a single run. Monochloroacetic acid and dichloroacetic acid showed good linearity in the range 0.1–20 and 0.15–20 μg/ml and correlation coefficients were 0.9999 and 0.9998, respectively. The detection limits (signal-to-noise ratio 3:1) of monochloroacetic acid and dichloroacetic acid were 17 and 25 ng/ml. This simple, sensitive, and time-saving method can be applied for composition analysis in acetic acid chlorination production.