肉类食品亚硝酸盐含量测定中应注意的问题

文章介绍了肉类食品亚硝酸盐含量测定中应注意的问题,以此提高检验结果准确度,减少测定中带来的各种误差.     

酸性镀铜液中氯离子的自动电位滴定

采用自动电位滴定法测定酸性镀铜溶液中的氯离子,研究了镀液中各种成分对测定的影响.本方法简便、快捷,分析结果准确可靠.     

气相色谱法快速测定空气中低分子量醛

本文作者用填充柱气相色谱法直接测定了污染空气中甲醛、乙醛、丙醛的含量,并对方法的灵敏度、准确度及各种影响因素进行了探讨。该法用于实际环境样品测定,取得了较为满意的结果。     

ICP—OES法测定硅锰、锰铁合金中磷含量

应用ICP—OES法测定硅锰、锰铁合金中磷的含量,对试样前处理及分析方法的各种参数进行了优化,包括溶样酸的选择,分析谱线的选择,试样基体、分析酸度和干扰元素对测定结果的影响。通过各种分析参数的优化选择实现了硅锰、锰铁中磷的测定,取得了满意的效果。线性相关系数：P=0．9998,检测限为：0．030％。该分析方法准确快速,试剂用量少,线性范围宽,适用于硅锰、锰铁合金中质量分数为0．03～0．50％的磷测定。     

红外吸收法测定不锈钢中硫量的不确定度评定

讨论了红外吸收法测定不锈钢中硫量的各种不确定度因素,并评定了该方法测定硫量的测量不确定度。     

表面结合的氧对活性炭疏水性和亲水性的影响

一、引言在研究活性炭表面化学的过程中,采用了许多运用各种测定技术的研究方法。有必要对测定表面化学特性所获得各种数据进行比较。本文用不同方法测定了五种由原料炭改性所获得的活性炭的化学性质。采用了下列技术:元素分析、酸碱反应、酸度滴定、热分解、红外光谱法、水和苯润湿热的量热测定法。水蒸汽吸附和Volta电位法。     

气体中微量水分析方法概述

概述了各种测定气体中微量水的分析方法：光腔衰荡光谱法、电解法、露点法、卡尔费休库仑法、重量法及碳化钙法的测定原理及其优缺点;并详细列举和归纳了不同种类气体产品测定水分含量所采用的方法,为企业和质监部门监控气体产品质量提供了可参考的技术信息。     

银镉合金无毒分析方法研究EI

该方法取消了银的分离，取消了剧毒品的使用，利用混合指示剂指示终点，直接进行锌镉的测定。同时用计算方法消除试样中镍的干扰，并用优选法对各种测定条件进行了最佳选择。     

微波辅助消解毛细柱气象色谱法测定蔬菜中的有机氯农药

研究了微波辅助消解毛细柱气象色谱法测定蔬菜样品中有机氯农药的分析方法。对各种有机氯农药的回收在79.8～105.7%之间,该方法具有快速、灵敏度高、精确度高、准确度高、进样量少等优点,使用于大批量蔬菜样品中有机氯农药的分析测定。     

食品添加剂二氧化碳中总硫的测定

介绍了采用火焰光度鉴定器进行了液体二氧化碳中总硫的测定以及消除各种干扰因素的方法。     

气体中痕量水蒸气测量技术进展

气体中水蒸气含量测量在工业生产和科研领域发挥至关重要的作用。随着许多工业生产和科研领域对气体水分含量更加严格的测试要求,对于气体中水蒸气含量测量灵敏度的要求也越来越高。目前测量nmol/mol痕量水分的仪器方法有可调谐二极管激光吸收光谱法、光腔衰荡光谱法、大气压离子质谱仪法;达到这个痕量水平的传感器类测量技术有石英晶体微天平法、冷镜露点法、阻容法、电解法。针对这些测量方法的优缺点以及今后的发展趋势进行了论述分析,通过克服测量过程中的干扰因素,可在一定的程度上提高痕量水含量的测量准确性,对促进痕量水含量准确测量技术的发展有所裨益。     

氮中微量氧气体标准物质的研制

采用GB/T 5274-1985《气体分析-校准用混合气体的制备-称量法》制备氮中微量氧气体标准物质。以称量法计算值叠加平衡气中氧含量值为定值,再经气相色谱法比对分析核验,通过对稳定性、压力变化、不确定度的评定和与国外购买的氮中微量氧气体标准物质的比对。结果证明我们配制生产的氮中微量氧气体标准物质稳定性好、均匀性好、不确定度小。     

Experimental estimation of the influence of the droplet evaporation process on the conditions of movement in an oncoming high-temperature gas flow

By means of high-speed video registration, the cross-correlation system, and panoramic optical methods of trace visualization, experimental estimation of the influence of liquid (water) droplet evaporation on the conditions of droplet movement (acceleration and deceleration) through the high-temperature (about 1100 K) gases was made. The experiments were conducted with droplets about 1–6 mm in diameter at start velocities of 1–5 m/s. We compare the integral characteristics of the droplet movement in the air at a temperature of about 300 K (in the ongoing flow and through the steady gas medium) and in the combustion product flow at a temperature of about 1100 K. The gas and the air flow velocities were about 1.5 m/s. The typical difference in the droplet velocities under essentially different ambient temperatures was discovered. The contribution of water evaporation and the ongoing gas movement into droplet deceleration was discovered.     

气体中微量氧分析测试方法综述

概述了气体中各种微量氧分析测试方法的原理、适用场合及分析注意事项，并列举了工业产品生产许可证中气体产品相关检测标准规定的分析方法及检测限要求，为气体生产及气体分析工作者提供了技术参考。     

Reducing the Uncertainty of Industrial Trace Humidity Generators through NIST Permeation-Tube Calibration

Permeation-tube moisture generators (PTGs) are commonly used by the semiconductor industry as transfer standards for the calibration of hygrometer systems measuring trace amounts of water vapor in gases (water vapor mole fractions typically below 1 × 10⁻⁶). They are relatively simple devices that generate a steady stream of humidified gas by diluting water vapor delivered at a constant rate from a permeable capsule with precisely metered purified gas, usually nitrogen. Here a new calibration service enabling the measurement of PTG permeation rates directly in terms of NIST primary standards of trace humidity generation is described. Rather than using commonly employed gravimetric methods for permeation-tube calibration, the method applied here links the permeation rate of the permeation tube to the thermodynamic properties of ice. Using a hygrometer based on cavity ringdown spectroscopy, we compare the water vapor concentrations produced by the NIST low frost-point generator (LFPG) and a specially constructed PTG containing the permeation tube undergoing calibration. A least squares fit of the data determines the permeation rate of the tube under test. We describe the calibration system, experimental procedure and present sample calibration data. The expanded relative uncertainty of NIST permeation-tube calibrations is 1.8% with a coverage factor k = 2, dominated by the Type A uncertainties.     

Fourier-Transform Infrared Differential Photoacoustic Spectroscopy (FTIR-DPAS) for Simultaneous Monitoring of Multiple Air Contaminants/Trace Gases

Air pollutants have severe impact on the global environment and the health of human beings. There is an urgent need for cost-effective devices for trace gas monitoring in ambient conditions. However, water vapor in ambient air is still an obstacle in the trace gas absorption detection field due to its complex and strong infrared absorbing characteristics. In this work, a step-scan Fourier-transform infrared differential photoacoustic spectroscopy (FTIR-DPAS) methodology developed in our laboratory through the introduction of two identical T-resonators for enhancing and resolving the DPA signal from two potentially pollutant gases is extended to multiple ambient gas components: carbon dioxide (CO₂) and acetylene (C₂H₂). A key feature of this technique is the ability to resolve hidden target spectral components in ambient air: Despite the fact that the acetylene absorption peaks lie within the strong water vapor absorption band, the infrared PA absorption spectra of acetylene and carbon dioxide are detected with high sensitivity and selectivity in the presence of significant interference of water vapor in the laboratory ambient air, thereby confirming the superiority and capability of step-scan FTIR-DPAS configuration to effectively and totally suppress often dominant background water signals and simultaneously detect multiple trace gases.     

Experimental determination of the retention time of reduced temperature of gas–vapor mixture in trace of water droplets moving in counterflow of combustion products

Technical Physics Letters - We have experimentally studied temporal variation of the temperature of gas–vapor mixture in the trace of water droplets moving in the counterflow of...     

热分解露点法测量超纯氨中的痕量水分

介绍了运用热分解露点法测量超纯氨气中微量水分的方法与设备。主要包括SH-7000冷镜式露点仪与热分解露点检测装置(TDDP)两部分。SH-7000露点仪基于冷镜式露点仪原理,采用微型专用制冷机,可准确地测量高纯气体的露点。TDDP系统基于氨气在高温环境下通过催化剂会发生不可逆的分解反应,而氨气中微量水分不会变化的原理,配合微量氧含量的测量,可准确得到氨气中的微水分含量。     

甲烷中微量气体标准物质分析方法研究及量值的比对（续二）

建立了甲烷中微量气体标准物质的分析方法和实验条件;考察了该分析方法的不确定度;得出甲烷中微量气体标准物质浓度在（1～50）×10-6（mol/mol）范围内,方法不确定度小于1%的实验结果。实验过程对重量法制备的系列气体标准物质量值进行了分析方法的比对,一致性验证结果在1%内吻合。该项研究成果代表国家最高实验室参与了国际计量委员会组织的CCQM-K66的关键比对,得到了满意的实验结果,获得了国际的等效度。