Research On Determination Of Forchlorfenuron In Kiwi Fruit Using Fluorescence Quenching Spectroscopy

As people in-depth knowledge and the rise of the global commercial development of kiwi fruit,kiwi fruit industry has been developing rapidly in China,and the cultivated area and yield are the first in the world.Because the forchlorfenuron can promote fruit enlargement,it was applied in kiwi fruit.In the process of kiwi fruit production,because of the farmers' devotion to production,they use overdosage forchlorfenuron,which seriousiy impact the inner quality of kiwifruit and hinders the development of kiwi fruit industry.And long-term exposure to forchlorfenuron may cause human body protein metabolism disorder and mild empHysema and thin.The existing detection methods have some advantages,for example technically mature,high precision.But there are some disadvantages,for example high technical requirements,sample pretreatment process complicated,time-consuming,high test cost,and last but not the least,they requires a large number of chemical reagents in the process of testing and it is difficult to detect quickly and greenly.It is not suitable for determination of forchlorfenuron in Kiwi fruit in conventional detection.So it is urgently need to find a kind of rapid,accurate,convenient,economical,safe,low cost and so on the characteristic of method to detect forchlorfenuron in Kiwi fruit and kiwi fruit industry sustainable and healthy development.The paper disscusses on the forchlorfenuron quenching mechanism of bovine serum albumin,and the optimum quenching conditions of forchlorfenuron in Kiwi fruit on bovine serum albumin.The fluorescence quenching spectroscopy and the chemometric methods were used to analyze and established the predictive model for detecting forchlorfenuron in Kiwi fruit.Specific results were as follows:(1)Fluorescence quenching spectroscopy study:bovine serum albumin best excitation wavelength and emission wavelength of 280 nm and 336 nm;A certain concentration of forchlorfenuron quenching bovine in different concentrations serum albumin solution,bovine serum albumin concentrations of optimal concentration of 1.5 x 10-5mol/L;under different temperature quenching test showed that chlorine pyrazole urea quenching is static quenching of bovine serum albumin.(2)The best conditions of forchlorfenuron in Kiwi quenching on bovirne serum albumin:ethyl acetate as the ideal extracting agent;When extracting 8.00g kiwi fruit samples,extracting agent for 16 ml,NaCl content is 0.8g,MgSO4 content is 1.2 g;the best pH of system is7,the temperature is 30?;within the scope of the test,in the time of forchlorfenuron in Kiwi fruit quenching effect of bovine serum albumin is not obvious.(3)The fluorescence quenching spectra combined with PLS method to measure the forchlorfenuron content in kiwi fruit as follows:quenching spectra data of the best pretreatment method is the SNV + SM + FD;choosing two principal components as spectral information after pretreatment of characteristic variables.The calibration set correlation coefficient(R2)of the true value and the prediction value was 0.9322,and the root mean square deviation(RMSECV)was0.02953;The validation set correlation coefficient(R2)of the true value and the prediction value was0.9254,predict root mean square error(RMSEP)of 0.02522.(4)Based on the two-dimensional correlation spectroscopy analysis of fluorescence quenching spectroscopy combined with BP neural network model was developed for the determination of forchlorfenuron content in kiwi method:After the samples of fluorescence quenching dealing with the second derivative spectra data,synchronously two-dimensional intensity of fluorescence spectrum matrix on the main diagonal of the data on the 301-399 nm for the input,for the concentration of the corresponding output neural network model is established.The structure of the artificial neural network mode was 50-16-1.Model of training set the correlation coefficient is 0.99307 and the correlation coefficient of the forecast of validation set is 0.96249.