Department of Fisheries and Oceans Northwest Atlantic Fisheries Centre St, John's, NFLD

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1 ISSN CANADIAN TRANSLATION OF FISHERIES AND AQUATIC SCIENCES No Determination of nitrogen or crude protein by means of an improved apparatus for quantitative distillation of steam-volatile substances by N. Antonacopoulos Original Title: Bestimmung des stickstoffs bzw, des rohproteins mit hilfe einer nverbesserten apparatur zur quantitativen destillation wasserdampffluchtiger stoffe" From: Z. Lebensm, Unters. Forsch. 113: , Translated by the Translation Bureau (NV) Multilingual Services Division Department of the Secretary of State of Canada Department of Fisheries and Oceans Northwest Atlantic Fisheries Centre St, John's, NFLD Pages typescript

2 14P Secretary Secrétariat of State d'état MULTILINGUAL SERVICES DIVISION DIVISION DES SERVICES MULTILINGUES z.-f 7-7 TRANSLATION BUREAU BUREAU DES TRADUCTIONS LIBRARY IDENTIFICATION FICHE SIGNALÉTIQUE Translated from - Traduction de German Author - Auteur Into - En English Nicolaus Antonacopoulos Title in English or French - Titre anglais ou français Determination of nitrogen or crude protein by means of an improved apparatus for quantitative distillation of steam volatile substances Title in foreign language (Transliterate foreign characters) Titre en langue étrangère (Transcrire en caractères romains) Bestimmung des Stickstoffs bzw. des Rohproteins mit Hilfe einer "verbesserten Apparatur zur quantitativen Destillation wasserdampffluchtiger Stoffe" Reference in foreign language (Name of book or publication) in full, transliterate foreign characters. Référence en langue étrangère (Nom du livre ou publication), au complet, transcrire en caractères romains. Zeitschrift ftir Lebensmittel Untersuchung und forschung Reference in English or French - Référence en anglais ou français (Journal of Food Research) Publisher - Editeur not shown Place of Publication Lieu de publication Year Année DATE OF PUBLICATION DATE DE PUBLICATION Volume not shown Issue No. Numéro Page Numbers in original Numéros des pages dans l'original Number of typed pages Nombre de pages dactylographiées 4 Requesting Department Ministère-Client Fisheries and Oceans Translation Bureau No Notre dossier no Branch or Division S.I.P.B. MV Direction ou Division Person requesting Demandé par Allan T. Reid Translation (Initials) Traducteur (Initiales) Your Number Votre dossier no E E Date of Request 19 January 1982 Date de la demande L. SEC (81/01)

3 e Secretary of State Secrétariat d'état MULTILINGUAL SERVICES DIVISION TRANSLATION BUREAU DIVISION DES SERVICES MULTILINGUES BUREAU DES TRADUCTIONS Client's No. No du client Department Ministère Division/Branch Division/Direction City Ville D F 0 S.I.P.B. Ottawa Bureau No. No du bureau Language Langue Translator (Initials) Traducteur (Initiales) German MV FEv,...,. Determination of nitrogen or crude protein by means of an improved apparatus for quantitative distillation of steam-volatile substances by Nicolaus Antonacopoulos Communication from the Institut für Fischverarbeitung der Bundesforschungsanstalt für Fischerei, HaMburg [Institute for Fish Processing of the Federal Fisheries Establishment, HaMburg] (Received 7 April 1960) With 1 figure in the text The determination of nitrogen or crude protein according to Kjeldahl is /116 one of the most frequently used laboratory methods which is employed, among other purposes, for the monitoring of nutritive value of food. In the fish processing industry for instance, the determination of the crude protein content is a measure of the quality of fish meals, but in general this method is used relatively little in this branch of the food industry. "M/t ::.. : ;. ;I EE SEC 5-25T (Rev. 6/78)

4 2 In fish industry laboratories where nitrogen determinations are carried out only occasionally, it is often not worth the expense to buy a separate apparatus such as the Parnas-Wagner apparatus for this purpose. However, the regulations on preservatives and foreign substances in foods enacted within the framework of the amendment to the Food Law have had the result that medium-sized and large enterprises of the fish industry increasingly take it upon themselves to monitor the preservative contents of their products. Most of the approved preservatives are separated out by means of steam distillation; in the fish industry the improved steam distillation apparatus described by this author in a previous publication l is often being used. By using a funnel tube - see Fig. 1 - and a descending Liebig condenser instead of the spiral condenser used in the standard apparatus, the device described in the publication referred to under l ean be used also /117 for ammonia distillation, a fact which makes it possible to avoid the purchase of a Parnas-Wagner apparatus which would be used only occasionally. When we compared the results obtained with the Parnas-Wagner apparatus and the apparatus described in this paper we found that the values agreed completely, and therefore we did not need to give any actual figures. Since the apparatus can be used practically continuously by merely exchanging the attachments it is even possible to conduct routine analyses with it. Exchanging the attachments does not require more time and effort than the corresponding operations with the Parnas- Wagner apparatus.

5 3 Fig. 1: Steam distillation apparatus (Federal German Utility Model) with funnel tube attachment for nitrogen determination) Directions for use Depending on nitrogen content, 5 or 10 ml of the Kjeldahl digestive solution are placed in the attachment, in continued use outside the steam generating flask, then the attachment is inserted in the preheated round-bottomed flask which is approximately 3/4 full with water, and is connected with the condenser via the bridge. The funnel tube is inserted into the ground opening of the bridge meant for this purpose and through the funnel the digestive solution is made alkaline by adding nitrogen-free, 33% sodium hydroxide. The ammonia is then distilled off in a steam flow and collected in a receiver with standard acid. The distillation time is 5 to 10 min. In all other respects the method follows that used for the Parnas-Wagner apparatus2, but the

6 4 stopcock attached to the side of the steam generating flask must be kept open until the liquid starts to boil. The steam is conducted into the pre-heated digestive solution only after the stopcock has been closed; this largely prevents dilution by condensing steam and thus a delay in the distillation. The rate of distillation can easily be controlled by regulating the gas flame accordingly. Contrary to the Parnas-Wagner apparatus it is possible with the apparatus described here to recover the digestive solution quantitatively, so that it can be used for further determinations. Summary The apparatus for quantitative distillation of steam-volatile substances, described in a previous publication l, can be adapted also to the determination of nitrogen or crude protein by inserting a funnel tube; this makes it unnecessary to purchase a Parnas-Wagner apparatus which would be used only occasionally. Bibliography 1 Antonacopoulos, N.: Zeitschrift fur Lebensmittel-Untersuchung und -forschung, Vol. 113, p. 113 (1960). 2 Determination of nitrogen; compare Beythien/Diemair: Laboratoriumsbuch fur den Lebensmittelchemiker [Laboratory manual for food chemists], 7th edition, page 5. Darmstadt: Th. Steinkopf 1957.