[Effect of mercuric chloride on the analysis of nitrites in pork products].

The effect of HgCl2 on nitrite determination was studied. 0,184 mmol/l to 184 mmol/l Hg Cl2 were added during the defecation or only at the time of analysis with an autoanalyser. Hg Cl2 was added to salami, bacon, dry sausage at different time of ripening and cooked ham. An effect was noted only when Hg Cl2 was added at the defecation time. After cold water extraction, the more the added Hg Cl2, the more "titrated" nitrite. After hot extraction with water and borate, the effect of Hg Cl2 was weaker but significant. The role of Hg Cl2 was important for the accurate determination of nitrites during the ripening of some products: in 16 hours old dry sausage the effect was weak (+40%), but became large (+600%) after 2 weeks of ripening. It is proposed to use Hg Cl2 at the concentration of 4 mmol/l for the determination of total nitrites. The free nitrites should be analysed separately without Hg Cl2.