摘要:

A spectrofluorimetric method for the determination of chlorpyriphos in apples, based on the inhibition of the acetylcholinesterase enzyme (AChE), has been established. The method employs a non-fluorescent synthetic enzyme substrate (Indoxyl acetate), which is hydrolyzed by the enzyme to yield a highly fluorescent product. In presence of the inhibitor, the rate of formation of this fluorescent product is lowered The rate of change in the fluorescence is measured ΔF/Δt. (λex= 395 λem= 470 nm). The simple spectrofluorimetric method described for the determination of chlorpyriphos in apple has a limit of detection of 13.68 μM with relative standard deviation of 7.1%. The method was applied to chlorpyriphos added (28.5 and 57 μM) to apples with recoveries ranged between 107% and 91%.

ISSN:0003-2719    

DOI:10.1080/00032719508002679

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A simple, sensitive and selective first derivative spectrophotometric method has been developed for the determination of copper and iron in mixtures. The method is based on the recovery of the analytes, by liquid-liquid extraction, integrated reaction with 5-phenyl-3-(4-phenyl-2-pyridinyl)-1,2,4-triazine (PPT) and perchlorate in dichloroethane and on the subsequent direct derivative spectrophotometric measurement using the zero-crossing approach for determination of both analytes. Copper and Iron were thus determined in the ranges 50 - 2500 ng/ml and 2-120 ng/ml, respectively, in the presence of one another. The detection limits achieved (3c, were found to be 17 ng/ml of copper and 0.7 ng/ml of iron. The relative standard deviations were in all instances less than 3.1%. The proposed method was applied to the determination of both analytes in well water and the results were consistent with those provided by the AAS standard method.

ISSN:0003-2719    

DOI:10.1080/00032719508002680

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A highly sensitive catalytic spectrophotometric method is proposed as a new method for the determination of Se(IV) and Se(VI). The method is based on the catalytic effect of Se(IV) in redox reaction of bromate with semicarbazide in hydrochloric acid media. The determination range of both analyses is 50-4000 ng.ml−1. Selenium as low as 43 ng. ml−1could be determined by this method. The application of the method to the determination of selenium in Kjeldahl tablets and in a health-care product is described.

ISSN:0003-2719    

DOI:10.1080/00032719508002681

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Tris(2-ethylhexyl)phosphate is proposed as an extractant for zirconium(IV) and hafnium(IV). The extraction conditions are established and reported. Log D - log C plots are used to ascertain probable extractable species. The method is used for selective separation of IVB group elements such as titanium(IV), zirconium(IV) and hafnium(IV). The method is applicable to the analysis of standard alloy samples and the results are reproducible and accurate.

ISSN:0003-2719    

DOI:10.1080/00032719508002682

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

ISSN:0003-2719    

DOI:10.1080/00032719508002683

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

ISSN:0003-2719    

DOI:10.1080/00032719508002684

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

ISSN:0003-2719    

DOI:10.1080/00032719508002668

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor