亞硝酸鹽對粗蛋白質(zhì)測定的影響及其測定方法的改進(jìn)研究
發(fā)布時(shí)間：2018-07-20 13:00
【摘要】：本試驗(yàn)將從鹽酸溶液濃度的標(biāo)定方法、蒸餾儀器的選擇、飼料中亞硝酸鹽含量等方面對飼料中粗蛋白質(zhì)含量測定時(shí)產(chǎn)生的影響以及飼料中亞硝酸鹽含量測定方法的比較及改進(jìn)進(jìn)行研究。凱氏定氮法是食品和飼料中測定粗蛋白質(zhì)應(yīng)用最廣泛也是最經(jīng)典的方法,其中鹽酸溶液濃度的標(biāo)定是凱氏定氮法中至關(guān)重要的一步,鹽酸溶液濃度的標(biāo)定方法分為無水碳酸鈉法和硼砂法。無水碳酸鈉標(biāo)定法需要在270℃~300℃干燥至恒重,操作較費(fèi)時(shí)費(fèi)事,且指示劑顏色不易把握;而硼砂標(biāo)定法中只說是干燥的硼砂,并未說明干燥程度以及如何干燥。蒸餾裝置是凱氏定氮法中的重要儀器,分為半微量蒸餾裝置和全自動(dòng)凱氏定氮儀等類型,不同蒸餾裝置對測定結(jié)果的影響尚無報(bào)道。試驗(yàn)表明:無水碳酸鈉須在270℃~300℃干燥至恒重才可標(biāo)定鹽酸。380℃干燥至恒重的硼砂在標(biāo)定鹽酸時(shí)計(jì)算式中的硼砂分子式要按無水硼砂計(jì)算;100℃干燥的硼砂不可以用于鹽酸標(biāo)定;正常室溫密閉存放的硼砂更適于北方地區(qū)實(shí)驗(yàn)室進(jìn)行鹽酸標(biāo)定(因?yàn)槟戏綕穸容^大)。全自動(dòng)凱氏定氮儀較半微量蒸餾裝置測定準(zhǔn)確性更好。亞硝酸鈉存在于飼料原料及配合飼料中,尤其在魚粉、肉骨粉及青綠飼料中含量較大,目前沒有試驗(yàn)研究表明飼料中亞硝酸鹽對其粗蛋白質(zhì)含量測定是否產(chǎn)生影響,但是通過人為向標(biāo)準(zhǔn)樣品硫酸銨中加入一定濃度梯度的亞硝酸鈉后,發(fā)現(xiàn)測出的硫酸銨中的氮含量減少,損失的氮含量與亞硝酸鈉的添加量呈現(xiàn)一定的線性關(guān)系。向牛血清白蛋白和飼料中加入亞硝酸鈉后會(huì)出現(xiàn)同樣的線性關(guān)系。試驗(yàn)表明:亞硝酸鹽的存在會(huì)對凱氏定氮法測定粗蛋白質(zhì)時(shí)產(chǎn)生一定的副作用,會(huì)與部分含氮化合物反應(yīng),降低蛋白含量的真實(shí)值,嚴(yán)重影響粗蛋白質(zhì)測定的準(zhǔn)確性。草酸是最簡單的有機(jī)二元酸之一,結(jié)構(gòu)簡式HOOCCOOH。NO2-中的N為+3價(jià),所以既有氧化性,又有還原性,在酸性介質(zhì)中呈現(xiàn)較強(qiáng)的氧化能力。與很弱的草酸、乙酸均可反應(yīng)�？赡艿姆磻�(yīng)為:2NO2-+2H+=NO+NO2↑+H2O。向加有不同濃度梯度亞硝酸鈉的硫酸銨混合物中分別加入0.1mol/l、0.5mol/l、1mol/l的草酸溶液,待反應(yīng)充分后加入濃硫酸。經(jīng)過試驗(yàn)結(jié)果分析得出:草酸溶液的加入不能消除亞硝酸鈉對粗蛋白質(zhì)測定的影響,所測出的硫酸銨中的氮含量與亞硝酸鈉的添加量仍然呈現(xiàn)一定的線性關(guān)系。為了對飼料中亞硝酸鹽含量進(jìn)行有效的檢測,首先要確定比較可靠、準(zhǔn)確的測定方法。飼料中亞硝酸鹽的測定方法分別為GB/T 13085—2005版和GB 13085—91版兩種。試驗(yàn)采用兩版國標(biāo)法對同一樣品進(jìn)行檢測,分別對兩種方法的準(zhǔn)確度和精確度進(jìn)行比較。同時(shí)對2005版前處理方法進(jìn)行改進(jìn),探討用于青綠飼料的測定。試驗(yàn)表明:亞硝酸鹽國標(biāo)檢測方法中2005版的精確度和準(zhǔn)確度均高于1991版,用2005版測定青綠飼料中亞硝酸鹽時(shí)加入1g活性炭可提高亞硝酸鹽的回收率,增強(qiáng)其測定的準(zhǔn)確性。
[Abstract]:This experiment will study the influence of the determination of the concentration of hydrochloric acid solution, the selection of the distillation instrument, the content of nitrite in the feed and the comparison and improvement of the method for determining the content of nitrite in feed. The Kjeldahl method is the application of the determination of crude protein in food and feed. The calibration of hydrochloric acid solution concentration is the most important step in Kjeldahl method. The calibration method of hydrochloric acid solution concentration is divided into anhydrous sodium carbonate method and borax method. The calibration method of anhydrous sodium carbonate should be dried at 270 ~300 C to constant weight, the operation is time-consuming and difficult, and the color of the indicator is not easy to grasp. The borax calibration method is only a dry borax, which does not indicate the degree of drying and how to dry. The distillation unit is an important instrument in the Kjeldahl method, which is divided into a semi micro distillation unit and a full automatic Kjeldahl nitrogen meter. The effects of different distillation units on the results have not yet been reported. The test shows that the anhydrous sodium carbonate must be at 270 ~300 The borax molecular formula in the calculation formula of hydrochloric acid.380 C drying to constant weight can be calibrated by drying to constant weight at centigrade to calibrate the borax molecular formula in the formula for hydrochloric acid to be calculated according to the anhydrous borax. The borax drying at 100 C can not be used for hydrochloric acid demarcation, and the borax stored in the normal room temperature is more suitable for the laboratory in the north area to carry out hydrochloric acid calibration (because the humidity in the south is larger). The accuracy of the Full Automatic Kjeldahl nitrogen meter is better than that in the semi microdistillation unit. Sodium nitrite is found in feed materials and compound feed, especially in fish meal, meat and bone meal and green feed. No experimental study has shown whether nitrite has an effect on the determination of its crude protein content in the feed, but by human direction. After adding a certain concentration gradient of sodium nitrite in the standard sample ammonium sulfate, it is found that the nitrogen content in the ammonium sulfate is reduced. The loss of nitrogen content is linearly related to the addition of sodium nitrite. The same linear relationship will appear after the addition of sodium nitrite to bovine serum albumin and feed. There will be a certain side effect on the determination of crude protein by Kjeldahl nitrogen method, which will react with some nitrogen compounds and reduce the true value of protein content, which seriously affects the accuracy of crude protein determination. Oxalic acid is one of the simplest organic dicaric acids, and the N in simple structure HOOCCOOH.NO2- is +3 price, so it has both oxidation and reduction. It can react with very weak oxalic acid and acetic acid. The possible reaction is that 2NO2-+2H+=NO+NO2 +H2O. adds 0.1mol/l, 0.5mol/l, 1mol/l to oxalic acid in the mixture of ammonium sulphate with different concentration gradient sodium nitrite, after the reaction is sufficient to add sulfuric acid. The analysis shows that the addition of sodium nitrite can not eliminate the effect of sodium nitrite on the determination of crude protein, and the nitrogen content in ammonium sulfate is still linear with the addition of sodium nitrite. In order to detect the content of nitrite in the feed, the first must determine a more reliable and accurate method. The determination method of nitrite in the material is GB/T 13085 - 2005 and GB 13085 - 91. The test uses two edition of national standard to test the same sample. The accuracy and accuracy of the two methods are compared respectively. At the same time, the pretreatment method of 2005 edition is improved and the determination of green fodder is discussed. The experiment shows that: nitrite The accuracy and accuracy of the 2005 edition of the 2005 edition of the acid salt national standard were all higher than that of the 1991 version. The addition of 1G activated carbon to nitrite in green feed could improve the recovery of nitrite and enhance the accuracy of the determination.
【學(xué)位授予單位】：東北農(nóng)業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：S816.17
本文編號(hào)：2133598
[Abstract]:This experiment will study the influence of the determination of the concentration of hydrochloric acid solution, the selection of the distillation instrument, the content of nitrite in the feed and the comparison and improvement of the method for determining the content of nitrite in feed. The Kjeldahl method is the application of the determination of crude protein in food and feed. The calibration of hydrochloric acid solution concentration is the most important step in Kjeldahl method. The calibration method of hydrochloric acid solution concentration is divided into anhydrous sodium carbonate method and borax method. The calibration method of anhydrous sodium carbonate should be dried at 270 ~300 C to constant weight, the operation is time-consuming and difficult, and the color of the indicator is not easy to grasp. The borax calibration method is only a dry borax, which does not indicate the degree of drying and how to dry. The distillation unit is an important instrument in the Kjeldahl method, which is divided into a semi micro distillation unit and a full automatic Kjeldahl nitrogen meter. The effects of different distillation units on the results have not yet been reported. The test shows that the anhydrous sodium carbonate must be at 270 ~300 The borax molecular formula in the calculation formula of hydrochloric acid.380 C drying to constant weight can be calibrated by drying to constant weight at centigrade to calibrate the borax molecular formula in the formula for hydrochloric acid to be calculated according to the anhydrous borax. The borax drying at 100 C can not be used for hydrochloric acid demarcation, and the borax stored in the normal room temperature is more suitable for the laboratory in the north area to carry out hydrochloric acid calibration (because the humidity in the south is larger). The accuracy of the Full Automatic Kjeldahl nitrogen meter is better than that in the semi microdistillation unit. Sodium nitrite is found in feed materials and compound feed, especially in fish meal, meat and bone meal and green feed. No experimental study has shown whether nitrite has an effect on the determination of its crude protein content in the feed, but by human direction. After adding a certain concentration gradient of sodium nitrite in the standard sample ammonium sulfate, it is found that the nitrogen content in the ammonium sulfate is reduced. The loss of nitrogen content is linearly related to the addition of sodium nitrite. The same linear relationship will appear after the addition of sodium nitrite to bovine serum albumin and feed. There will be a certain side effect on the determination of crude protein by Kjeldahl nitrogen method, which will react with some nitrogen compounds and reduce the true value of protein content, which seriously affects the accuracy of crude protein determination. Oxalic acid is one of the simplest organic dicaric acids, and the N in simple structure HOOCCOOH.NO2- is +3 price, so it has both oxidation and reduction. It can react with very weak oxalic acid and acetic acid. The possible reaction is that 2NO2-+2H+=NO+NO2 +H2O. adds 0.1mol/l, 0.5mol/l, 1mol/l to oxalic acid in the mixture of ammonium sulphate with different concentration gradient sodium nitrite, after the reaction is sufficient to add sulfuric acid. The analysis shows that the addition of sodium nitrite can not eliminate the effect of sodium nitrite on the determination of crude protein, and the nitrogen content in ammonium sulfate is still linear with the addition of sodium nitrite. In order to detect the content of nitrite in the feed, the first must determine a more reliable and accurate method. The determination method of nitrite in the material is GB/T 13085 - 2005 and GB 13085 - 91. The test uses two edition of national standard to test the same sample. The accuracy and accuracy of the two methods are compared respectively. At the same time, the pretreatment method of 2005 edition is improved and the determination of green fodder is discussed. The experiment shows that: nitrite The accuracy and accuracy of the 2005 edition of the 2005 edition of the acid salt national standard were all higher than that of the 1991 version. The addition of 1G activated carbon to nitrite in green feed could improve the recovery of nitrite and enhance the accuracy of the determination.
【學(xué)位授予單位】：東北農(nóng)業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：S816.17
【參考文獻(xiàn)】
相關(guān)期刊論文 前7條
1 王欽振;;論溫石棉結(jié)構(gòu)水含量的測定和計(jì)算——兼評加拿大《溫石棉檢驗(yàn)手冊》中的算式[J];非金屬礦;1993年05期
2 俞玉忠,倪明敏,劉申敏;消化時(shí)間對總氮測定結(jié)果的影響[J];海峽藥學(xué);2004年03期
3 白鳳翎;雙縮脲法測定飼料中蛋白質(zhì)含量[J];糧食與飼料工業(yè);2003年03期
4 安國民;唐偉英;楊曉民;;測定飼料中粗蛋白質(zhì)含量應(yīng)注意的幾個(gè)問題[J];糧食與飼料工業(yè);2006年05期
5 謝平會(huì),楊征武,祝麗玲;電流法快速測定鮮奶中蛋白質(zhì)含量[J];中國乳品工業(yè);2000年04期
6 李寧;;幾種蛋白質(zhì)測定方法的比較[J];山西農(nóng)業(yè)大學(xué)學(xué)報(bào)(自然科學(xué)版);2006年02期
7 陸曉濱,李敬龍,董貝磊,馬美范;提高凱氏定氮法蛋白質(zhì)測定速度的研究[J];中國調(diào)味品;2003年01期
，本文編號(hào)：2133598
本文鏈接：http://sikaile.net/yixuelunwen/dongwuyixue/2133598.html
最近更新
教材專著
