苏州市食品中苯甲酸(钠)含量调查分析

以液相色谱仪器作为检测手段,对苏州市食品中苯甲酸(钠)含量进行调查,发现包装酱菜苯甲酸含量不合格率为13%,散装酱菜不合格率为59%,黄酒、月饼、果汁饮料均检出苯甲酸(钠)但未超标。散装酱菜苯甲酸超标严重,市场上食品中苯甲酸(钠)添加情况令人担忧。

防腐剂苯甲酸(钠)测定方法的研究进展

苯甲酸(钠)作为食品防腐剂,合理地使用可以有效延长食品的保质期,但过量的添加则会直接损害人类的身体健康。为了保证食品安全,需要找到一种简便、快速及高灵敏度的苯甲酸(钠)测定方法。该文论述了近些年来测定苯甲酸(钠)的多种方法,如高效液相色谱法、气相色谱法、离子交换色谱法、纸色谱法、薄层色谱法、紫外分光光度法、毛细管电泳法、动力学荧光法、滴定分析法和发光细菌法等,为苯甲酸(钠)的测定提供参考。

高效液相色谱法同时测定面包糕点中苯甲酸(钠)、山梨酸(钾)、安赛蜜、糖精钠和脱氢乙酸(钠)的含量

面包糕点中的苯甲酸(钠)、山梨酸(钾)和脱氢乙酸(钠)、安赛蜜和糖精钠经溶解、离心、过滤后,采用高效液相色谱法同时测定,样品标准加入回收率分别为94.2%～101.6%、93.6%～102.7%、90.8%～99.1%、92.5%～102.3%、91.1%～99.5%,RSD分别为1.8%～10.3%、1.5%～11.2%、1.2～9.5%、1.2～6.8%、1.7%～10.9%。

关于GB/T5009.29-2003高效液相色谱法对食品中山梨酸、苯甲酸的测定的探讨

对国家食品卫生检验方法 GB/T 5009.29-2003《食品中山梨酸、苯甲酸的测定》进行探讨。采用高效液相色谱法同时对面包样品的山梨酸、苯甲酸含量进行测定:得出苯甲酸含量测定结果平均RED为0.3,回收率为97.8%,山梨酸测定结果平均RED为0.2,回收率为98.1%;并对实验中出现的状况进行分析解决。

高效液相色谱法同时测定食品中安赛蜜、苯甲酸( 钠) 、山梨酸( 钾) 、脱氢乙酸( 钠) 和糖精钠

目的研究一种快速、准确、简单的高效液相色谱法同时测定食品中安赛蜜、苯甲酸(钠)、山梨酸(钾)、脱氢乙酸(钠)和糖精钠等5种添加剂。方法根据样品类别选择不同的前处理方法,以甲醇∶乙酸铵(pH=6.8)=5∶95(体积比)作为流动相,利用二极管阵列检测器(DAD)检测样品的特征吸收光谱图,以保留时间定性,外标法定量分析。结果5种标准品的最大吸收波长分别为安赛蜜225.89 nm、苯甲酸226.87 nm、山梨酸254.97 nm、糖精钠268.68 nm、脱氢乙酸232.45 nm和292.62 nm。在1μg/ml^200μg/ml浓度内具有良好的线性关系(r=0.9999),检出限为0.001 mg/g^0.005 mg/g,回收率为96%~98%,相对标准偏差为0.19%~1.0%。结论本方法利用NaOH和乙酸锌作为蛋白共沉淀剂,能有效去除样品中蛋白,提高了方法的灵敏性,能快速实现各类食品中5种添加剂的同时检测。

高效液相色谱法同时测定食品中苯甲酸(钠)、山梨酸(钾)、安赛蜜、糖精钠和脱氢乙酸(钠)的研究

探讨采用高效液相色谱法同时测定食品中的苯甲酸、山梨酸、安赛蜜、糖精钠和脱氢乙酸五种食品添加剂含量的方法。样品经超声提取,采用C18色谱柱,以0.02mol/L乙酸胺一甲醇为流动相,用二极管阵列检测器于230 nm波长处检测。该方法灵敏度高,重现性和选择性好,回收率高,易于操作,是检测食品中5种添加剂的有效定量方法。

Effects of particle size and particle interactions on scheelite flotation

Effects of size distribution (particle size and content of fine fraction (<10μm)) on scheelite flotation were studied using flotation tests and theoretical calculations. The results show that particle size influences the scheelite recovery and the performance of combined reagents. The scheelite recovery is lowered by adding fine particles (<10μm) into the pulp containing coarse particles. Extended DLVO (EDLVO) theory confirms that the fine fractions (<10μm) could interface with the coarse fractions. The interaction energy and fluid forces are relative to the particle size, which might explain why the fine fractions influence the scheelite flotation. The highest recovery of scheelite using combined reagents as collector and optimum ratio of combined reagents were determined by scheelite particle size and reagent performance. However, the optimum adding order was only determined by reagent performance, which has nothing to do with particle size.

Selective flotation of smithsonite from dolomite by using novel mixed collector system

A novel mixed collector (BHOA) was prepared by mixing benzohydroxamic acid (BHA) and sodium oleate (NaOL) and applied to the flotation separation of smithsonite from dolomite. Flotation results showed that NaOL alone had good collecting performance on smithsonite and common gangue mineral dolomite but had poor selectivity. By using a BHA/NaOL mixed system with a molar ratio of 2:1, the recoveries of smithsonite and dolomite reached approximately 90% and 5%, respectively. Surface tension analysis showed that the surface activity of BHOA was a little higher than that of a single NaOL because of synergistic effects. Zeta potential and X-ray photoelectron spectroscopy measurements indicated that surfactants BHA and NaOL co-absorbed on the smithsonite surface and only NaOL was present on the dolomite surface in the presence of BHOA.

食品防腐剂影响微生物指标检验结果的机制

选择卫生部门与相关检查单位所提供的含防腐剂食品样品416份,采用多种培养基试剂进行检验测试,分析防腐剂苯甲酸(钠)、山梨酸(钾)对微生物真菌计数和菌落总数的影响。结果表明,防腐剂对菌落总数和真菌计数检测结果的影响随着防腐剂浓度的增加更显著,苯甲酸(钠)和山梨酸(钾)2种防腐剂菌落总数并未显著性差异,山梨酸(钾)对真菌计数产生的影响高于苯甲酸(钠)。

Synthesis and Application of Sodium Benzoylthioglycollate to Cotton Fabric

The paper discussed the synthesis and application of sodium benzoylthioglycollate (BTG) to cotton cellulose. The main product was proved to be BTG. Dyeing substantivity of modified cotton fibre by BTG with disperse dye were improved. The effect of modification conditions, such as the property of alkali and its using amount, curing temperature and time were discussed. Colour yield and resistance to wash fastness were also measured.

Kinetic Parameters Determination Using Reaction Calorimetry： Study of Sodium Benzoate Synthesis

A modified systematic approach to determination of the kinetics of well known reaction from calorimetric data is addressed in this study. Because the application of calorimetry does not depend upon knowledge of concentration profiles, it has the advantage over other real-time analyses. Estimated kinetic parameters were compared with the ones obtained with Fourier Transform Infrared Spectroscopy （FTIR）. The chosen reaction was ethyl benzoate saponification performed in homogeneous reaction medium, although it is known as heterogeneous reaction. Thus, the rate expression was developed where no mass transfer is considered. The reaction was carried out in a MettlerTM RCI reaction calorimeter.

Oxidative Desulfurization of Diesel Fuel with Hydrogen Peroxide Using Na_2WO_4 as Catalyst

Oxidative desulfurization was performed on Na2WO4 catalyst in the presence of hydrogen peroxide and acetic acid under mild reaction conditions （atmospheric pressure and temperature range of 293--343 K）. Different organic compounds including benzothiophene （BT）, dibenzothiophene （DBT）, 4, 6-dimethyl dibenzothiophene （4, 6-DMDBT） were used to investigate the reactivity of this catalyst, and the effect of various parameters, such as temperature, solvents and the amount of oxidant reagent used in oxidative desulfurization reaction, was also examined. The results showed that the Na2WO4- H202 system was very effective for oxidative desulfurization, and the oxidation of BT, DBT and 4, 6-DMDBT was influenced by different parameters.

Kinetic Rate Constant of Liquid Drainage from Colloidal Gas Aphrons

A kinetic model fitted by the empirical equation has been proposed to describe the liquid drainage behavior. Rate constants （kd） of liquid drainage equation could be obtained from the above empirical equation. In this paper, the stability of the colloidal gas aphrons （CGAs）, the effect of concentrations of sodium dodecyl benzene sulphate （SDBS）, dodecyl trimethylammonium bromide （HTAB） and polyoxyethylene sorbitol anhydride monolaurate（Tween-20）, temperature, stirring speed, stirring time, and various kinds of salts on the kd of liquid drainage are further investigated. The results show that the Arrhenius equation can be successfully used to describe the relation between kd arid absolute temperature （T）, and concentrations of surfactants, stirring speed, stirring time and salinities also have great effect on the kd. At last, the CGAs drainage mechanism is explained from analysis of the rate of liquid drainage as a function of time.

食品防腐剂对菌落总数检测影响的研究

研究几种常用食品防腐剂对风味饮料、果汁饮料菌落总数检测可能存在的影响。结果表明,食品防腐剂在使用限量范围内,样品菌落总数检测结果与对照样菌落总数检测结果没有显著性差异,因此可以认为,食品防腐剂不会对菌落总数检测产生影响。

Studies on the roles of vanadyl sulfate and sodium nitrite in catalytic oxidation of benzyl alcohol with molecular oxygen

An efficient catalytic system consisting of vanadyl sulfate/sodium nitrite was disclosed previously for the oxidation of benzylic alcohols into aldehydes with molecular oxygen.However,the roles of catalyst components were not investigated.In this paper,we examined catalytic oxidation of benzyl alcohol as a model reaction,especially by infrared spectroscopy.The role of each component is discussed including nitrite,vanadyl,sulphate,and water.Sodium nitrite could be converted into nitrate and nitric acid.The vanadium(IV)could be smoothly oxidized into vanadium(V)under mild and acidic conditions without any organic ligands.The transformation of sulfate and bisulfate,the cessation of an induction period,and the oxidation of benzyl alcohol were closely interrelated.The multiple roles of water are discussed,including reduction of the induction period,participation in redox cycles of nitric compounds,deactivation of vanadium,and as a byproduct of oxidation.This study contributes to further development of aerobic oxidation using vanadium based catalysts.

Analysis of treatment regimen in a pregnant patient with ornithine transcarbamylase deficiency

As a common urea-cycle disorder, ornithine transcarbamylase deficiency(OTCD) disables the conversion of ammonia into non-toxic urea, and its subsequent excretion results in hyperammonemia. We reported a 28-year-old woman who was diagnosed with OTCD during her first pregnancy. She was treated with arginine, citrulline and sodium benzoate for complications associated with hyperammonemia, and her protein intake was restricted. The patient’s condition was stabilized, and she delivered a baby boy via cesarean section. However, the baby died 2d later. During her second pregnancy, prenatal screening suggested that the fetus had OTCD, and an induced abortion was performed. During her third pregnancy, fetal OTCD was ruled out, and the patient was treated with oral sodium benzoate. Her blood ammonia level was stabilized, and a baby boy was successfully delivered via cesarean section. This case described the treatment process of the pregnant patient with OTCD, and the safety and efficacy of sodium benzoate were evaluated. Collectively, our findings provided the experience and evidence for the drug selection and treatment of these rare diseases.