烟用接装纸中二异丙基萘的测定

通过改变烟用接装纸的前处理方法,GC-MS色谱柱的选择和升温程序的设置,优化了测定烟用接装纸中二异丙基萘的方法。降低了检出限,缩短了二异丙基萘的检测时间,提升工作效率。二异丙基萘的回收率在92.5%~103.5%之间,RSD为4.79%,线性相关系数0.9925,检出限达到0.25mg/kg。本方法检出限低、准确度高、精密度好、简便快捷,适用于烟用接装纸中二异丙基萘含量的检测。     

水性触感油在烟用接装纸上的应用研究

以水性聚氨酯乳液为主树脂,水性苯丙乳液为辅助树脂,搭配滑爽助剂、消泡剂、 pH调节剂和溶剂,制备出具有特殊功能的水性触感油,并将其应用于烟用接装纸。通过考察不同组分及含量对触感层的外观效果、附着力、耐磨性、手感舒适度、抗返黏性、动/静摩擦系数、接触角等参数的影响,结合实际上机打样验证,筛选出具有良好印刷适应性的水性触感油配方及其印刷工艺,进一步制备出消光效果好、耐磨性好、抗返黏性优良、环保、手感舒适的触感型烟用接装纸产品。     

pH值对模拟胃液可迁移六价铬分析方法的影响

在日常检测中,当采用模拟胃液可迁移模型对涂层材料进行六价铬检测时,较容易出现六价铬假阳性现象。采用阴离子交换柱分离三价铬和六价铬,经离子色谱联用电感耦合等离子体质谱仪(IC-ICP-MS)检测可迁移六价铬,发现中和步骤中pH值对玩具材料的可迁移六价铬的检测结果有重大影响。必须将pH值严格控制在7～8之间。当中和步骤pH值增大,高风险材料中的三价铬离子容易被氧化,使得六价铬含量随之增加,出现假阳性现象,导致错误结论。     

pH值对模拟胃液可迁移六价铬分析方法的影响

在日常检测中,当采用模拟胃液可迁移模型对涂层材料进行六价铬检测时,较容易出现六价铬假阳性现象.采用阴离子交换柱分离三价铬和六价铬,经离子色谱联用电感耦合等离子体质谱仪(IC-ICP-MS)检测可迁移六价铬,发现中和步骤中pH值对玩具材料的可迁移六价铬的检测结果有重大影响.必须将pH值严格控制在7～8之间.当中和步骤pH...     

4种烟用框架纸中溶剂残留的测定及比较分析

为了测定4种类型框架纸中26种溶剂残留,文章优化建立了顶空-气相色谱/质谱联用法。在优化的检测条件下,26种化合物的相关系数均大于0.9979,回收率为80.5%～109.5%,相对标准偏差均在6.1%之内,检出限为0.002～0.237 mg/m²,因此该方法稳定可靠。结果表明：印刷框架纸中溶剂残留量最高,白(乳)框架纸中溶剂残留量最低。导致此差异的原因可能是不同框架纸的工艺流程、印刷方式以及油墨配方、印后处理方式等方面的不同。因此,卷烟企业在选用框架纸时,可以选择性的使用安全风险小的白(乳)框架纸,以降低框架纸使用的安全风险。     

气相色谱法同时测定功能接装纸13种酸味剂

建立了气相色谱法同时测定功能接装纸种13种酸味剂的检测方法.通过单因素考察,确定前处理最优化方案,酯化温度为90℃,料液比为1:12,酯化时间为110min,萃取次数为3次.目标化合物分离效果较好,相关系数均在0.999以上,检出限为0.10～0.16mg/mL,定量限为0.32～0.53mg/mL.该方法操作简单、灵...     

气相色谱-质谱联用法同时测定烟用香精中6种添加剂

建立了气相色谱-质谱联用法同时测定烟用香精香料中6种添加剂(黄樟素、芝麻酚、香豆素、β-萘酚、β-细辛醚、咖啡因)的分析方法。香精香料经二氯甲烷震荡萃取,提取液净化浓缩后采用GC-MS的选择离子监测方式(SIM)对6种添加剂进行定性定量分析。6种添加剂(黄樟素、芝麻酚、香豆素、β-萘酚、β-细辛醚、咖啡因)的检出限为0.025~0.075 mg/kg,在0.5,2.0,10 mg/kg添加水平下的回收率为85.2%~104.6%,相对标准偏差为1.4%~8.1%。方法能够满足烟用香精中6种添加剂的检测要求。     

接装纸/胶搭配对滤嘴通风率的影响

为了探究纸/胶搭配对滤嘴通风率的影响及作用机理,对6种纸/胶搭配卷烟样品的无胶区面积及滤嘴通风率进行了测定与分析。结果表明:1)接装胶会显著影响无胶区面积及滤嘴通风率,接装纸仅显著影响滤嘴通风率。2)无胶区面积与滤嘴通风率呈正相关关系,且在同种纸不同胶的情况下达到了显著水平。因此,接装纸、胶均会显著影响滤嘴通风率,但作用机理不同;合理的纸/胶搭配有利于提高滤嘴通风率稳定性。     

离子色谱法测定六价铬的研究进展

文章概述了近年来采用离子色谱测定六价铬的方法,包括了离子色谱电导检测法(IC-CD),离子色谱紫外检测法(IC-UV),离子色谱-电感耦合等离子体质谱法(IC-ICP-MS)的方法研究情况,对未来发展进行了展望。     

Chromium(VI) reduction using conducting polymer films

Reduction of highly toxic hexavalent chromium (Cr(VI)) to its trivalent state (Cr(III)) is necessary to enable further treatment of wastewater by precipitation or adsorption. For this purpose, the present study proposes the use of thin polyaniline films deposited on a large surface area substrate reticulated vitreous carbon (RVC). The influence of electric potential, flow velocity and supporting electrolyte on the reaction rate, current efficiency and energy consumption was investigated for bare RVC and polyaniline-covered RVC. The film stability was also evaluated. The polyaniline thickness was not observed to influence the reaction rate. Also, the synthesis conditions must be controlled in order to guarantee that the substrate surface is completely covered by the polymer. The supporting electrolyte was observed to influence the energy consumption, but not the reaction rate. Flow velocity is very important for process optimization since it improves the mass transfer. Finally, the polyaniline-modified electrode is a promising material for use in Cr(VI) reduction as it remained stable after several cycles and no loss in the reduction rate was observed.     

Floe Foam Flotation of Chromium(VI) with Polyelectrolytes

Abstract

The separation efficiency of the floe foam flotation of chromium(VI) with Fe(II) from aqueous solutions with high ionic strength can be improved by adding a very small amount of polyelectrolyte (either cationic or anionic polymer) as an activator. The possible mechanisms by which flotation is affected by polyelectrolytes are discussed. The effects of the order of the addition of the reagents (polyelectrolyte and base) on flotation and sedimentation are also studied. It was found that effective separation of chromium(VI) by floe foam flotation with Fe(II) can be achieved for a rather wide range of initial chromium(VI) levels by using the same treatment parameters.     

Removal of Chromium(VI) and Chromium(III) from Aqueous Solution by Grainless Stalk of Corn

Abstract

Grainless stalk of corn (GLSC) was tested for removal of Cr(VI) and Cr(III) from aqueous solution at different pH, contact time, temperature, and chromium/adsorbent ratio. The results show that the optimum pH for removal of Cr(VI) is 0.84, while the optimum pH for removal of Cr(III) is 4.6. The adsorption processes of both Cr(VI) and Cr(III) onto GLSC were found to follow first-order kinetics. Values of k _ads of 0.037 and 0.018 min^?1 were obtained for Cr(VI) and Cr(III), respectively. The adsorption capacity of GLSC was calculated from the Langmuir isotherm as 7.1 mg g^?1 at pH 0.84 for Cr(VI), and as 7.3 mg g^?1 at pH 4.6 for Cr(III), at 20°C. At the optimum pH for Cr(VI) removal, Cr(VI) reduces to Cr(III). EPR spectroscopy shows the presence of Cr(V) + Cr(III)-bound-GLSC at short contact times and adsorbed Cr(III) as the final oxidation state of Cr(VI)-treated GLSC. The results indicate that, at pH ≈ 1, GLSC can completely remove Cr(VI) from aqueous solution through an adsorption-coupled reduction mechanism to yield adsorbed Cr(III) and the less toxic aqueous Cr(III), which can be further removed at pH 4.6.     

Chromium electrodeposition from Cr(VI) low concentration solutions

This work presents a study of a hard chromium plating process using low concentration H₂CrO₄ baths. In particular, the effect of different values of CrO₃/H₂SO₄ ratio on coating properties such as adhesion, hardness, surface roughness, apparent density and microstructure were considered. To increase the solution conductivity, avoiding long deposition times and low throwing power typical of dilute solutions, the behaviour of various inorganic compounds was investigated. Specifically, the compounds suitable for obtaining brighter coatings with lower surface roughness values than those obtained using Fink’s solutions were Na₂SO₄ and Al₂(SO₄)₃ × 18H₂O. A bath composition was identified, with a limited use of Cr(VI) in a solution able to produce coatings with a better surface roughness than those of conventional industrial baths.     

Removal and Recovery of Chromium(VI) from Industrial Waste Water

Carbon slurry, generated as a waste material in a naphtha-based ammonia plant of the Fertilizer Corporation of India, Gorakhpur, has been used as an adsorbent for the removal of Cr(VI) from aqueous solution at different experimental conditions. The removal was favoured at low pH, with maximum removal at pH 2·5. The effects of concentration and temperature have also been reported. Batch adsorption kinetics have been described by the Lagergren equation. The applicability of the Langmuir isotherm for the present system has been tested at different temperatures. Thermodynamic parameters indicate the endothermic nature of Cr(VI) adsorption on carbon slurry. Recovery of adsorbed chromium for reuse has also been reported in the present study. © 1997 SCI.     

液相色谱法快速测定废水中的六价铬

建立了废水中六价铬的快速测定方法,样品由液相色谱进样经C18预柱净化,经二苯卡巴肼溶液衍生显色后543nm处测定。本方法的标准曲线线性良好,检出限可达0.002mg/L以下。而且灵敏度高,方法快速、稳定,可应用于日常检测。     

水泥中水溶性铬（Ⅵ）的限量及测定方法（GB 31893—2015）第1号修改单解读

水溶性六价铬是重金属中毒性较大的元素之一,含有较高水溶性六价铬的水泥产品在生产、流通、使用及废弃环节均会对人身健康产生严重影响,同时会造成严重的环境污染。《水泥中水溶性铬（Ⅵ）的限量及测定方法》（GB 31893—2015）规定采用分光光度法测定水泥中水溶性铬（Ⅵ）的限量值应不大于10.00 mg/kg。为保持标准的适应性和准确性,采用修改单形式对GB 31893—2015进行修订。本文主要简述了GB 31893—2015《水泥中水溶性铬（Ⅵ）的限量及测定方法》国家标准第1号修改单中的修订内容;进行了变更的检测方法与原检测方法的对比试验,同时进行了不同厂家指示剂对检测结果的误差分析,可为实际检测提供参考。