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131.
Pivnichny JV 《Journal of pharmaceutical and biomedical analysis》1984,2(3-4):491-500
The two isomeric components of glycerol formal, 1,3-dioxan-5-ol and 1,3-dioxolane-4-methanol, are marginally separated (Rs = 1.0) by polar-bonded-phase high-performance liquid chromatography (HPLC) on a cyanopropyl column with acetone—hexane as the eluent. Esterification of these components with 3,5-dinitrobenzoyl chloride produces derivatives which are, however, completely resolved (Rs > 2) by normal-phase HPLC on silica; derivatization has the added advantage of introducing an ultraviolet-absorbing chromophore into each component. Preparative scale chromatography is used to isolate each of the derivatives, which are characterized by their UV, NMR and mass spectral properties. These esters are used as reference standards for an analytical method based on derivatization and normal-phase chromatography. In this way a sample of glycerol formal is calibrated for use as a standard in the direct determination of the two components by polar-bonded-phase HPLC. 相似文献
132.
Adrenaline was determined in injections containing procaine in a 1000-fold excess by reversed-phase high-performance liquid chromatography using UV detection at 205 nm and aqueous sulphuric acid (100 μmol/l) as eluent. The relative standard deviation was 2.1%, and the method was selective in the presence of adrenaline degradation products. Changes of the capacity factor with pH and ionic strength of the eluent were studied, and a simple model is suggested to explain the retention data. 相似文献
133.
Yeung ES 《Journal of pharmaceutical and biomedical analysis》1984,2(2):255-263
A micropolarimeter interfaced to a liquid chromatograph is shown to be suitable for selective monitoring of the optically-active components in complex samples. When an optically-active eluent is used, indirect determination of even optically-inactive materials is possible, down to the level of 10 ng of an injected component. If a second chromatogram is obtained using the racemic analogue of the optically-active eluent, quantitation can be achieved without standards and without prior analyte identification. This concept is also applicable to the refractive index detector, the absorption detector and the conductivity detector in the special case of ion chromatography, and the ultrasonic detector in gas chromatography. 相似文献
134.
Krejci M Slais K Kourilová D Vespalcová M 《Journal of pharmaceutical and biomedical analysis》1984,2(2):197-205
The advantages of microbore columns for trace analysis by liquid chromatography are identified, with reference to on-column enrichment techniques performed on analytical micro-columns. The selectivity and high sensitivity of the amperometric detector are utilized in combination with a microbore column for a number of pharmaceutical and bioanalytical analyses, including phenothiazines, parabens, sulphonamides, catecholamines, tetracyclines, vitamins, amino acids and dipeptides. 相似文献
135.
136.
Optimum support properties for protein separations by high-performance size exclusion chromatography
Optimum chromatographic properties of high performance size exclusion chromatography (HPSEC) of proteins, such as resolution, molecular weight accuracy and recovery, are obtained on packings and columns with tailor-made physical and chemical structures, employed at properly adjusted eluent compositions and operation conditions. SEC-theory suggests that a broad molecular weight fractionation range and high linearity of the log-linear calibration plot can be achieved by the use of two packings (10- and 80-nm pore size, characterized by a pore-size distribution (psd) equal to or less than 1 decade and by equal internal column porosity (p)), rather than a single 30- to 50-nm pore-size packing with a wide psd. Favourably high-phase ratios of (p)/(o)/ 1.0 for HPSEC columns were accomplished with a minimum interstitial column porosity (o) and a high value for the internal column porosity (p) (the specific pore volume, nu(p), multiplied by the packing density, varrho(p).) Ligands such as diol, N-acetoxyamino and oligomeric ether with a propyl- or propoxy-spacer bonded to the silica at the highest density appear to provide high mass recovery and bioactivity as well as chemical stability. Such packings, available in 3-5 mum particle size ranges of narrow distribution, packed into columns 6 mm i.d. and 500 mm in length, offer the best compromise with respect to resolution, speed and pressure drop. More careful studies are required to explain the effects of protein conformational changes and interconversions during elution on HPSEC columns. 相似文献
137.
van Rooij HH Pirovano IM Soudijn W 《Journal of pharmaceutical and biomedical analysis》1984,2(1):91-99
Methods have been developed for the determination of nicomorphine using reversed-phase HPLC with UV detection; for the simultaneous assay of morphine and mononicotinoylmorphine by a coupled normal-phase HPLC-radioimmunoassay method; and for conjugates of morphine and mononicotinoylmorphine by radioimmunoassay. The methods have been evaluated and applied to a pharmacokinetic study of nicomorphine administered intramuscularly. 相似文献
138.
目的 建立蜂蜜中氯霉素、甲砜霉素、氟甲砜霉素及甲硝唑残留的高效液相色谱-串联质谱同时测定方法。方法 以乙酸乙酯作为提取剂,经涡旋混匀提取后,氮吹至干,用5%甲醇水溶解,Oasis HLB固相萃取柱净化。经甲醇洗脱,洗脱液经45℃水浴氮吹至干,流动相涡旋溶解,上机测定。高效液相色谱分离、串联质谱检测,采用多离子反应监测(MRM)模式,内标法定量。结果 在优化条件下,4种抗生素浓度在0.1~5.0μg/L范围内,线性关系良好,相关系数(r)≥0.9953,方法检出限≤0.015μg/kg,不同基质中平均加标回收率为78.5%~95.1%,相对标准偏差(RSD)为2.8%~10.7%。结论 该方法快速、灵敏、准确,适用于蜂蜜中氯霉素、甲砜霉素、氟甲砜霉素及甲硝唑的同时测定。 相似文献
139.
固相微萃取技术测定塑料浸取液中邻苯二甲酸二辛酯 总被引:1,自引:0,他引:1
目的 探讨塑料浸取液中邻苯二甲酸二辛酯 (DEHP)的测定方法。方法 采用聚硅氧烷和富勒烯聚二甲基硅氧烷混合固定相自制萃取头 ,利用顶空固相微萃取与气相色谱联用技术 (HS -SPME -GC)分析塑料浸取液中邻苯二甲酸二辛酯 ,研究萃取时间、热解吸时间、溶液的酸碱度和离子强度等因素对方法灵敏度的影响 ,并与商用聚二甲基硅氧烷 (PDMS)萃取头比较。结果 该萃取头的萃取选择性优于PDMS萃取头 ,方法具有良好的线性范围(0 .4~ 5 0 0 μg·L-1) ,最低检出限为 0 .15 μg·L-1,相对标准偏差为 4.9% (n =6 )。结论 固相微萃取技术分析水样中邻苯二甲酸二辛酯具有高效、灵敏、操作简单、无需溶剂等优点。 相似文献
140.