DIN ISO 20370:2012-10

The International Standard ISO 20370 has been published in July 2009 as a result of consultations at ISO/TC 126 "Tobacco and tobacco products" (secretariat: Germany) on the determination of the citrate content of material used to produce wrappings for cigarette filters, cigarettes and other tobacco products. The standardization project has been submitted by Germany and is based on the International Standard DIN 10370. Working Committee NA 057-04-01 AA "Tabak und Tabakerzeugnisse" ("Tobacco and tobacco products") of the Food and Agricultural Products Standards Committee (NAL) at DIN decided to transfer ISO 20370 into the German body of standards. The working committee took its decision in particular from the point of view of a necessary harmonization of the international and national standards in the field of tobacco and tobacco products. This standard specifies a method for the determination of the acetate content of material used to produce wrappings for cigarette filters, cigarettes and other tobacco products. The acetate content is determined by an enzymatic method. During the process acetate (acetic acid), catalysed by the enzyme acetyl coenzyme A synthase with adenosine 5'-triphosphate and coenzyme A, is first converted to acetyl coenzyme A, adenosine 5'-monophosphate and pyrophosphate. Catalysed by citrate synthase (CS), acetyl coenzyme A reacts with oxaloacetate to form citrate. The oxaloacetate required for the reaction is formed from malate and nicotinamide-adenine dinucleotide by catalysis using L-malate dehydrogenase. The determination is based on the formation of NADH, which is measured by the increase in absorbance at 340 nm. Since the determination reaction is preceded by an indicator reaction, the amount of NADH formed is not linearly proportional to the acetate content. The standard supersedes DIN 10370:1998-06. With respect to this standard a warning note has been included and the normative references have been updated. The absorption wavelength has been specified to be 340 nm, furthermore an example of a suitable product for reagent mixtures and filter paper has been included. Equation (6) has been aligned. Conditioning is now to be in accordance with ISO 187 instead of DIN EN 20187; the determination of the moisture content is now to be in accordance with ISO 287 instead of DIN EN 20287 (unchanged procedures). Furthermore, the standard has been editorially revised and brought in line with the current rules of presentation. The committee responsible for this standard is NA 057-04-01 AA "Tabak und Tabakerzeugnisse" ("Tobacco and tobacco products") at DIN.