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 Posted: Sun 9:28, 20 Feb 2011 Post subject: Capillary gas chromatography of potassium bromate |
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Capillary gas chromatography of potassium bromate content of bread
Sensitivity, in the selected sample is relatively small when the flow ratio (1 / 50). Figure 1-butanone in the FFAP column bromine separation of Figure 2. Linearity and detection limits: sample treatment solution and potassium bromate concentration of 0.050 ~ 1.000g/ml a good linear relationship when the regression formula is Y = 2.564 × 10. A 2.83 × 10,[link widoczny dla zalogowanych], r = 0.9991. 3 times the instrument noise by calculating the detection limit of 5 × 10. g / ml, while samples taken 1g detection limit when measured 5 × 10g/kg. 3. Recovery and precision: the same samples by adding 40.0g of potassium bromate,[link widoczny dla zalogowanych], parallel to the determination of 6, the recoveries were 90.9%, 111.2%, 98.7%,[link widoczny dla zalogowanych], 102.2%,[link widoczny dla zalogowanych], 108. 4% and 100.4%, = 101.97%, s = 7.24%, RSD = 7.10%. 4. Analysis of test results of samples: June 2006 Workshop from l0 home bread bread and bread flour were collected from the 1, and the other collected from the four grain store 1 copy of plain flour, potassium bromate content of which were measured,[link widoczny dla zalogowanych], the result is: l0 servings of bread were lower than 0.005g/kg (2 copies <0.0005g/kg, 8 were in the 0.0009 ~ 0.0012g/kg), l0 servings of bread flour and 4 ordinary powder <0.0005g/kg . Can be seen from the end of the value of the flour is very low, does not affect the determination of the results. September 2005 detected l0 servings of bread, of which potassium bromate content is lower than 0.01g/kg have 2 copies, there are more than 1 0.05g/kg, 0.01 ~ 0.05g/kg have 7 copies , indicating that prohibited use of potassium bromate is very serious, as technology development, the new regulator has reached the dough a good gluten enhancement, can replace potassium bromate. Bread from the bread flour with the corresponding results of comparison between the point of view, most of the measured value is higher than bread flour, for reasons yet to be identified. 5. Factors: (1) ash samples is a key factor in the process, to ensure that the sample was wet and full of sodium carbonate to maintain sufficient alkaline, or a fixed base is not volatile escape of bromine will be caused by the results low. Flour and water to the deep experience is not easy to infiltrate, so the determination of flour, sodium carbonate and zinc oxide are added after the need to stick with a small glass and mix well. (2) the concentration and amount of sulfuric acid has a direct impact on the results, less than the amount of potassium dichromate oxidation of bromide ion will reduce the oxidation efficiency; high concentration of sulfuric acid will have dissolved when the heat of the solution temperature, evaporation of elemental bromine is a strong substances, higher temperatures likely to be volatile in the escape of. In both cases the cause is a result of the low side. (3) the experiment is not the specific determination of bromate, which determined the result was the total amount of bromide ion in the sample (in terms of potassium bromate), so when the sample contains the results of other substances containing bromine will be high. The raw materials used in bread flour in natural bromine content is low, mainly from external contamination in the cultivation, storage process using methyl bromide, ethyl bromide, ethylene bromide, bromine and other pesticides deltamethrin J. Methyl bromide fumigation of serious environmental pollution due to human toxicity greatly, the world has been gradually banned as food fumigant use J. Brominated pesticides generally have a strong volatility in food storage, processing residual concentration is very low, usually does not affect the determination of bromate. To be prudent, can be detected in samples of potassium bromate in flour, the raw material for further testing bromine (as potassium bromate) content, by deducting the value of the background to get an accurate measurement results. (4) halogen element, bromine and iodine ions in the plasma in the experimental system can occur with the addition reaction of methyl ethyl ketone methyl ethyl ketone and bromine, iodine, respectively, methyl ethyl ketone generated out of the peak, the retention time of iodine than bromine butanone butanone Large, clear separation of the two peaks, interference will not occur. Fluoride and chloride ions does not occur with the addition reaction of methyl ethyl ketone. Selected References [1] in the rainbow. Safety of Potassium Bromate and alternative way. China Food Additives, 2002, (1) :1-4. [2] Gu Jianhua, XU Ai-ping, Yang Lihong. Determination of content of potassium bromate in bread. INFORMATION ON PREVENTIVE MEDICINE ,1998,2:110-111. [3] with the Pharmaceutical Society of Japan Journal of Preventive Medicine assembler. Health test comment. Beijing: Chinese Press ,1995:475-476. [4] Wang Haitao, Zhang Rui, Duan security, and so on. Capillary gas chromatography of methyl bromide in food content. Port Health Control, 2004,1 (9) :16-18.
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