Analysis Method Study Of Benzaldehyde Derivatives Isomers Base On Chemometrics-UV

Benzaldehyde derivatives are very significant intermedia, which is widely used in chemistry and chemical engineering. But lots of benzaldehyde derivatives have isomers, especially derivate from the different substitute position in benzene cycle. Because of their similar chemical and physical character and easy oxidation, benzaldehyde derivatives isomers anlysis are very difficult. Chemometrics-ultraviolet spectrophotometry is cheap, easy and fast. The study use it to detemind benzaldehyde derivatives, and contains some aspects as follows:(1) It was established 14 molds to simulataneous determine chlorobenzaldehyde isomers’mixture. The molds have good predicted capability and they are suitable for real sample anlysis except GA-BP and GA-PCA-BP. The detection range of every isomer is 1-12 μg/mL and the absorbency data of 230-300nm was used to computer. The molds’RMSEP range of o-, m-and p-hydroxylbenzaldehyde is 0.19-0.29,0.03-0.19,0.06-0.11 μg/mL, and RMSE range is 0.03-0.19,0.02-0.0.14 and 0.014-0.16μg/mL. F test (a=0.1) show that the variance of P-matrics, GA-P, GA-PCR, GA-PLS, GA-KF, GA-BP, GA-PCA-BP、GA-KF are significant difference from some other molds. Recovery of most added test is between 80-120%. The best molds are PCR, PLS, GA-PCR, GA-PLS and GA-PCA-RBF in 14 molds in hydroxylbenzaldehyde isomers’mixture analysis.(2) It was established 12 molds to simulataneous determine chlorobenzaldehyde isomers’mixture. The molds have good predicted capability and they are suitable for real sample anlysis. The detection range of every isomer is 2-12μg/mL and the absorbency data of 250-330nm was used to computer. The molds’RMSEP range of o-, m-and p-hydroxylbenzaldehyde is 0.12-0.85,0.24-1.00 and 0.07-0.64μg/mL, and RMSE range is 0.03-0.19, 0.02-0.0.14 and 0.014-0.16μg/mL. F test (α=0.1) show that the variance of P matrics, GA-P, GA-PLS, GA-K are significant difference from some other molds. Recovery of all added test is between 80-120%. The best molds are PCR, PLS and GA-K in 12 molds in hydroxylbenzaldehyde isomers’mixture analysis.(3) A novel method was presents, which was based on the composite application of the iterative algorithm, the partial least squares (PLS) and the ultraviolet spectrophotometry. It is used to simultaneously determine the three tolualdehyde isomers among the six components prepared by indirect electrosynthesis with the xylene. The PLS was enchased to the iterative algorithm to obtain the approximation through the interactive calculations, which could improve the spectrum identification ability of the products. The proposed method has been applied to simultaneous determination of three tolualdehyde isomers in 4 simulating samples with satisfactory results. The mean recovery of o-tolualdehyde, m-tolualdehyde and p-tolualdehyde were 97.9%,100.5%and 100.4%, and root mean square errors of prediction (RMSEP) were 0.242,0.171 and 0.061, respectively. The practical application to five group electrosynthesis tolualdehyde products showed that the average recovery were 106.5,91.8 and 99.7% for o-, m-and p-tolualdehyde, respectively, and the relative error was less than 19.7%, and the results of determination were compared with those of HPLC with no signification difference.