共查询到20条相似文献,搜索用时 78 毫秒
1.
目的:建立顶空气相色谱-质谱联用法测定食品中亚硫酸盐含量的方法。方法:样品在顶空瓶内与磷酸介质发生反应使得产物二氧化硫(Sulfur dioxide, SO2)溢出,在恒温下达到气液两相平衡状态。采用GS-GASPRO气相色谱柱分离,经电子轰击离子源(Electron impact ion source, EI)电离后以总离子流(Total ion current, TIC)模式进行数据采集与分析,依据保留时间及质谱信息定性,标准曲线法定量。结果:该方法在5.0~5 000.0μg/mL质量浓度范围内呈良好线性,相关系数r2=0.999,检出限(limits of detection, LODs)为0.336 mg/kg,定量限(Limits of quantitation, LOQs)为1.120 mg/kg。测得竹笋、酸菜等五种样品的加标回收率在91.3%~108.8%,相对标准偏差(Relative standard deviations, RSDs)小于6%(n=6)。应用方法对多种样品进行检测,其中蔬菜罐头类以及腌渍食品检测结果多为... 相似文献
2.
本文用顶空气相色谱法,测定了空气中的环氧乙烷,用GDX-102作分离柱,作温120℃,线性范围是0.51-10.2μmg/mL,相对标准偏差3.2%。. 相似文献
3.
4.
5.
6.
7.
8.
9.
10.
建立了测定可可色素中的丙酮残留的方法。将可可色素溶解于水中,水浴加热,顶空进样,GC-FID检测,通过保留时间定性,外标直线法定量。实验表明,当平衡时间为50min,平衡温度为40℃,盐析剂为NH4Cl且用量为0.4g时,丙酮的回收率为93.5%-100.8%,相对标准偏差为3.21%。分析结果表明顶空气相色谱法测定可可色素中的丙酮残留量方法操作简便、快速、准确性和精密度良好。 相似文献
11.
12.
Dr. Satish R. Malwal Dr. Kundansingh A. Pardeshi Dr. Harinath Chakrapani 《Chembiochem : a European journal of chemical biology》2020,21(8):1201-1205
Although sulfur dioxide (SO2) finds widespread use in the food industry as its hydrated sulfite form, a number of aspects of SO2 biology remain to be completely understood. Of the tools available for intracellular enhancement of SO2 levels, most suffer from poor cell permeability and a lack of control over SO2 release. We report 1,2-cyclic sulfite diesters as a new class of reliable SO2 donors that dissociate in buffer through nucleophilic displacement to produce SO2 with tunable release profiles. We provide data in support of the suitability of these SO2 donors to enhance intracellular SO2 levels more efficiently than sodium bisulfite, the most commonly used SO2 donor for cellular studies. 相似文献
13.
用气相色谱法测定工业氢气中微量CO和CO2的含量,考察了转化温度、氢氮比、助燃气流量等诸因素对测定结果的影响。试验表明,方法有较高的灵敏度及准确度,适合工业氢气中微量CO及CO2的控制分析。 相似文献
14.
15.
16.
本文在分析国内外有关文献的基础上,提出了人造轻骨料膨胀气体的高温连续在线测定的新方法:将自行研制的微型密封高温炉(室温 ̄1500℃)直接与气相色谱仪相连,试验结果对传统膨胀模式提出了挑战-即试样在膨胀温度范围内产生的气体,并非“被适宜粘度的液相所包围”,而是一直强烈地逸出;试样膨胀过程实际上是“在膨胀温度范围内的膨胀气体猛烈地冲击着粘度适宜的试样液相并一直强烈逸出”的动平衡过程。同时精确测出了页岩 相似文献
17.
A dream of many pharmaceutical companies is to be able to register a large design space with the regulatory agencies. The problem is that this will require both time and money, so an intelligent method of validating a design space is needed. The design space should only cover operating points at which the process runs optimally. This means that the process should be optimized for different process scenarios and objective functions and the found operating points should be registered as design space. This paper presents a method of determining a good design space by creating Pareto fronts for the ideal case and for various process disturbance scenarios. Optimal operating points are found for varying ratios between feed costs and operating costs, making it possible to make a quantitative choice of an operating point based on this ratio and a qualitative choice based on the whole front. The analysis will show how the chromatographic process can be made more robust when optimizing for higher yields, and how the effect of the critical process parameters can change. To be certain that a robust process is found and that it has a high performance, process disturbances must be taken into account when optimizing a process. 相似文献
18.
19.
20.
2003年济钢焦化厂引进焦炉煤气精脱萘工艺,利用柴油循环脱萘。鉴于精脱萘工艺柴油成分复杂,混合物性质极为相近的特点,开发了采用气相色谱法测定循环柴油中萘含量的分析方法,并确定了其检测条件。该法操作简便、快速,数据准确,其检测结果为精脱萘工艺生产提供了及时、准确的指导数据。 相似文献