Food safety problems caused by excessive nitrite addition have been frequently reported and the detection of nitrite in food is particularly important. The standing time during the pretreatment of primary sample has a...Food safety problems caused by excessive nitrite addition have been frequently reported and the detection of nitrite in food is particularly important. The standing time during the pretreatment of primary sample has a great influence on the concentration of nitrite tested by spectrophotometric method. In this context, three kinds of food samples are prepared, including canned mustard, canned fish and home-made pickled water. A series of standing times are placed during the sample pretreatments and the corresponding nitrite contents in these samples are detected by spectrophotometric method based on N-ethylenediamine dihydrochloride. This study aims to find out a reasonable standing time during the pretreatment of food sample, providing influence factor for precise detection of nitrite.展开更多
A series of poly-aluminum-chloride-sulfate (PACS), which has different basicities (gamma) and Al3+/SO42- molar ratio, has been prepared and dried at 105degreesC and 65degreesC, respectively. The distribution of alumin...A series of poly-aluminum-chloride-sulfate (PACS), which has different basicities (gamma) and Al3+/SO42- molar ratio, has been prepared and dried at 105degreesC and 65degreesC, respectively. The distribution of aluminum species of PACS was examined, and the effect of 7 value, Al3+/SO42- molar ratio, dilution on the distribution of aluminum species of PACS was also investigated by using Al-ferron timed complex colorimetric method. The IR spectroscopy and X-ray diffraction were used to study the effect of gamma value, Al3+ / SO42- molar ratio and the drying temperature on the structure of PACS. The experimental results show that Al3+/SO42- molar ratio has a great effect on the distribution of aluminum species, but the dilution has a little effect on the distribution of aluminum species. The lower the Al3+/SO42- molar ratio, the higher the proportions of the polymer and colloidal species in PACS, The polymeric degree of PACS was related to gamma value and Al3+/SO(4)(2-)molar ratio. Drying temperature has an influence on the structure and the solubility of solid PACS products.展开更多
文摘Food safety problems caused by excessive nitrite addition have been frequently reported and the detection of nitrite in food is particularly important. The standing time during the pretreatment of primary sample has a great influence on the concentration of nitrite tested by spectrophotometric method. In this context, three kinds of food samples are prepared, including canned mustard, canned fish and home-made pickled water. A series of standing times are placed during the sample pretreatments and the corresponding nitrite contents in these samples are detected by spectrophotometric method based on N-ethylenediamine dihydrochloride. This study aims to find out a reasonable standing time during the pretreatment of food sample, providing influence factor for precise detection of nitrite.
文摘A series of poly-aluminum-chloride-sulfate (PACS), which has different basicities (gamma) and Al3+/SO42- molar ratio, has been prepared and dried at 105degreesC and 65degreesC, respectively. The distribution of aluminum species of PACS was examined, and the effect of 7 value, Al3+/SO42- molar ratio, dilution on the distribution of aluminum species of PACS was also investigated by using Al-ferron timed complex colorimetric method. The IR spectroscopy and X-ray diffraction were used to study the effect of gamma value, Al3+ / SO42- molar ratio and the drying temperature on the structure of PACS. The experimental results show that Al3+/SO42- molar ratio has a great effect on the distribution of aluminum species, but the dilution has a little effect on the distribution of aluminum species. The lower the Al3+/SO42- molar ratio, the higher the proportions of the polymer and colloidal species in PACS, The polymeric degree of PACS was related to gamma value and Al3+/SO(4)(2-)molar ratio. Drying temperature has an influence on the structure and the solubility of solid PACS products.
