Studies On Methods Of Determination Of Formaldehyde And Mechanisms Of Formaldehyde-producing In Aquatic Products

For lacking of formaldehyde standard determination methods to employ in monitoring inspection item in the aquatic products, here we have ascertained three kinds of qualitative methods and two kinds of quantitative methods including spectrophometer and HPLC and their parameters. At the same time we have set up the data base of instinct formaldehyde content in aquatic products using established methods and determined the influence of TMAO-ase on formaldehyde-producing in aquatic products.According to characteric of some chemicals which can react with formaldehyde to come into being special colour,we have ascertained three qualitative methods including methods of phyloroglucinoe,Ferric chloride and sodium nitroferricy anlde to attain the goal of formaldehyde determination. The least determination was separately 1ug/mL,0.5ug/mL and 1ug/mL.And the color stability time was separately 2min ,2h and 5min. Using water distillation free and reversibly bound formaldehyde in the aquatic products was distilled out and measured by spectrophometer at 413nm. The color stability time was lOh.The average recovery of water-risen ,fresh and living,dried aquatic products, shrimp was separately 90.04%,76.05%.64.54% and 60.14%. The least determination was 0.022 ug/mL.This method can be used to determine formaldehyde content in aquatic products,for having good standard curve linear relation, good sensitivity and little interaction.HPLC can also be used todetermine formaldehyde content ,for undirectly determining formaldehyde content by the reaction between FA and DNPH. The least determination is 7.2 ug/L. And at the same time we have ascertained three existence waysrfree formaldehyde,reversibly bound formaldehyde and bound formaldehyde by using abstraction of TCA.steam distillation and calculation of DMA.The origination of uncertainty,the calculation and combination of each input quanity eventually were put forward according to the research on the assay and the evaluation of uncertainty in the determination of formaldehyde in aquatic products by spectrophometer.It showed that the uncertainty mainly came from concentration and repeated examinations we must strictly obey examination norm.By established determination methods of formaldehyde ,we have determined instinct formaldehyde content in aquatic products including water and scawater fish,shellfish,shrimp and crab,total 74 species.We found the amount of instinct formaldehyde of seawater fish was higher than water fish.And the amount of formaldehyde in gadoid fish was the highest. Using non-gadoid fish and gadoid fish as materials,we have known mass formaldehyde can be produced in gadoid fish especially added gut.There was plenty of TMAO-ase in gadoid fish gut,which can produce formaldehyde.In order to diminish harm of formaldehyde to people.we used different processing ways and found oil-fry was the best way to eliminate formaldehyde. So in gadoid fish processing, blood and gut ought to be thoroughly taked off, and gadoid fish and non-gadoid fish must be conserved separately.