A Novel Mothod Based On Vector-subspace Angle Criterion And The Applieation For Detecting The Paraben Esters Within Cosmetics

Multicomponent system of quantitative problem has traditionally the focus anddifficulty in analytical chemistry, usually quantitative analysis be done after separation orreaction. Establish quantitative analysis without separation of multi-component system is achallenging task. In this paper, through the studying of vector subspace criterion, achieve adirect quantitative t analysis of multicomponensystem is not isolated. The ultimate goal ofquantitative analysis is to service for production and life. Paraben ester in cosmetics areused to analyze because of the illegally added for food and daily necessities in recent yearsrepeatedly or even worse. Cosmetic samples without separation were analysed by usingUV spectrophotometric and vector-subspace angle criterion and achieving fast analysis. Atthe same time, the calibration transfer method being studied, unequivocal use of existingdata accumulation background database, improving methods versatility and lower cost ofanalysis. Research contents include:(1) The feasibility of vector-subspace angle criterion is verified.Creating a set of UVspectra similar to Rayleigh distribution density curve, the calculation results byvector-subspace angle criterion consistent with actual values. At the same time, the resultsshow that the noise and the losing of rank and so has little impact to vector-subspace anglecriterion.(2) An UV-Vis spectrophotometric method was appointed for the determination ofparaben ester in cosmetics. The sample spectrum was designated by establishingbackground spectrum library and standard spectral library, and using vector deductiblemodel calculation. The result indicates that the methodology exhibited excellent linearityfor Paraben ester in the range of0.25-10mg/L(r>0.9992). The relative error is less1.2%and the RSD is lower than1.7%. The analytic results of the proposed method are similarto those obtained by the HPLC method.(3) In this paper, HPLC-UV and space angle criterion was combined to analyzeparaben esters in cosmetics. Background spectrum library which does not contain parabenesters developed by HPLC method for separation of the sample, meanwhile the samplespectrum was identified by establishing background spectrum library and standard spectrallibrary, and using space angle criterion calculation. The result indicates that the analyticalresults of the proposed method are comparable obtained from the method of HPLC, therelative error is less5.00%. Recoveries for paraben esters are ranged from97.95%to101.83%, and the RSD is1.05%.(4) The database model migration and applied to the similar instruments. Thebackground database can accumulate by existed data through calibration transfer, whichcan avoid repeating build database established between different instruments. the passedbackground database combination of database with vector-subspace criterion for determining the content p-hydroxy benzoic acid ester in cosmetics, The results showthat: the interpolation method combined with piecewise standardization after passing thebackground database with model exactly with the results without passing the establishedbackground database, The relative error less than0.2%.