摘要:

A validated method has been developed to quantify the amount of zinc undecenoate and undecenoic acid in a commercial athlete's foot cream matrix by liquid-liquid extraction followed by gas chromatography and titration method. Gas chromatography was used to analyse the total amount of undecenoic acid and a titration method was used to quantify the amount of zinc ion present in the mixture.

ISSN:0003-2719    

DOI:10.1080/00032719908542825

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A rapid first-derivative spectrophotometric method for the simultaneous determination of naphazoline nitrate and tetramethylthionine base in eye drops by using zero-crossing measurements is described. Solutions of this drug combination in water were analysed by measurement of the amplitudes at 257.2 and 247.5 nm, respectively. Good linearity, accuracy, precision and selectivity were found, and the method is proposed for routine quality control purposes.

ISSN:0003-2719    

DOI:10.1080/00032719908542826

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The similarity in the chemical structure of hesperidin and diosmin represents a difficulty in determining one or both of them when present together in pharmaceutical dosage forms.

ISSN:0003-2719    

DOI:10.1080/00032719908542827

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The emission produced by sulfite in its oxidation by periodate in acidic solution in the presence of Ru(phen)32+is used to determine 1.0x10−7to 1.5x10−4mol/L sulfite. The limit of detection is 7x10−10mol/L and the relative standard deviation is 2.3% for a 4x10−5mol/L sulfite solution (n=9). The method was applied satisfactorily to the determination of sulfur dioxide in air by using triethanolamine (TEA) as absorbent material.

ISSN:0003-2719    

DOI:10.1080/00032719908542828

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A novel method has been developed for the determination of trace La, Eu and Y in high purity ZrO2by electrothermal vaporization inductively coupled plasma atomic emission spectrometry (ETV-ICP-AES) with 1-phenyl-3-methyl-4-benzoyl-5-pyrazone (PMBP) as extractant and chemical modifier. The matrix was quantitatively separated from the selected elements in 6M HNO3medium by extraction with 0.1M PMBP in chloroform. The vaporization behaviors, effect factors and analytical characteristics of above selected elements were investigated in detail. Under the optimized conditions, the detection limits were 8.0, 0.9 and 1.0ng ml−1for La, Eu and Y with the relative standard deviations of 3.3, 3.4 and 4.0% (n=7, c=0.5 μg ml−1), respectively. The proposed method has been applied to determine trace impurities in ZrO2.

ISSN:0003-2719    

DOI:10.1080/00032719908542829

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Liquid chromatographic comparisons are made between a secondary amide linked chiral stationary phase (CSP 1) and a tertiary amide double-tethered CSP (CSP 2) derived from (S)-N-3,5-[dinitrobenzoyl(DNB)]leucine. For the enantioseparation of the anilide derivatives of N-9-fluorenylmethoxycarbonyl (FMOC), benzyloxycarbonyl (CBZ) and t-butoxycarbonyl (BOC) protected α-amino acids, CSP 2 shows performance superior to that of CSP 1. It is considered that the amide hydrogen of the connecting tether of CSP 1 serves as a nonproductive adsorption site, while the enhanced basicity of the carbonyl oxygen of the tertiary amide tethered CSP 2 is responsible for the increased enantioselectivity of these analytes. For the same reason, it is observed that CSP 2 provides better separation of the enantiomers of N-CBZ α-amino acids as ethyl ester, n-butylamide and diethylamide derivatives than CSP 1.

ISSN:0003-2719    

DOI:10.1080/00032719908542830

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor