TRANSFORMATION OF VALUES OF AMINO-N IN SUGAR-BEET FOR APPLICATION IN THE REINEFELD FORMULA USING ALUMINUM SULFATE AS CLARIFICATION AGENT AND A FLUOROMETRIC METHOD FOR AMINO-N DETERMINATION

In the past, the photometric blue number method has been used for dete rmination of alpha amino N in order to characterize the technological value of sugar beet in Germany. Since the late eighties, a new fluorom etric method using OPT for determination has been adopted for analytic al and environmental reasons, i.e. replacement of toxic lead acetate a s clarifying agent by aluminium salts. Aluminium sulphate in compariso n to lead acetate has no significant effect of the value alpha amino N , whereas using the fluorometric OPT method consistantly higher values are achieved when compared with the blue number method. The Reinefeld formula is used to estimate the technological quality of sugar beet i n Germany. In this formula, the content of alpha amino N is considered , which has been measured by the blue number method. In order to take the systematic effect of the new method into account, a simple factor is applied to convert fluorometric into blue number values in most bee t laboratories. Scientifically speaking, the application of a regressi on would be appropriate. By the application of a factor instead of a r egression differences may arise due to different mathematical ways of correction. These artificial differences may be crucial when absolute values of a amino N are compared.