利用电感耦合等离子体质谱法(ICP-MS)测定锡矿尾砂中的铜铅锌镉铬钴镍

土壤中重金属元素含量将直接威胁环境生态安全,对不同矿产资源进行成分测定能够为环境生态风险评估工作提供重要参考依据。通过选取某锡矿尾砂作为待测样品,采用HNO_(3)-HCl进行样品前处理,结合测试精度要求进行仪器参数设置优化,并以Rh标准储备溶液为内标、选定7种元素的同位素,运用ICP-MS方法进行待测样品中Cu、Pb、Zn、Cd、Cr、Co、Ni多金属元素的同步测试。结果:Cu、Pb、Zn、Cd、Cr、Co、Ni 7种元素标准曲线的线性相关系数均高于0.9999,检出限控制在0.003~0.120μg/L范围内,方法精密度控制在0.87%~3.72%,标准物质的测试结果满足要求,加标回收率超过97.2%。该方法简便快捷、稳定好、准确性高,适合同时测定锡矿尾砂中的铜铅锌镉铬钴镍,具备良好应用价值。

利用电感耦合等离子体质谱法(ICP-MS)测定锡矿尾砂中的铜铅锌镉铬钴镍

土壤中重金属元素含量将直接威胁环境生态安全,对不同矿产资源进行成分测定能够为环境生态风险评估工作提供重要参考依据。通过选取某锡矿尾砂作为待测样品,采用HClO_(4)-HF-HNO_(3)法进行样品前处理,结合测试精度要求进行仪器参数设置优化,并以Rh标准储备溶液为内标、选定7种元素的同位素,运用ICP-MS方法进行待测样品中Cu、Pb、Zn、Cd、Cr、Co、Ni多金属元素的同步测试。测试结果显示,各元素的检出限均处于0.003~0.12μg/L这一范围,对应加标回收率在97.2%~101%之间,具备良好应用价值。

Measurement and Correlation of Solubilities of Adipic Acid in Different Solvents

Using a simple and reliable apparatus, the solubilities of adipic acid in water, ethanol, chloroform, n-butanol and acetone are determined by the analytic method. The results are correlated with λh equation, Apelblat equation, and UNIFAC equation. The solubilities calculated by these models are in good agreement with experi-mental data, so that the models can meet the requirements of engineering design.

Kinetic study on selective extraction of HCl and H_3PO_4 in a microfluidic device

In the extraction method for preparing KH2PO4, one of the key processes is the selective extraction of HCI over H3PO4. In our work, extraction kinetic studies have been carried out in a microfluidic device with a coaxial microchannel, using the extractant of 33.3% （by volume） trioctylamine （TOA） dissolved in n-octanol, with differ- ent aqueous phases： the HCI solution, the H3P04 solution, and H3PO4 and KCI solutions of different concentra- tions. The changes of the extraction efficiency of HC1 and H3P04 and the selectivity for HC1 along with the residence time were investigated. We found that fast extraction kinetics could be realized in microfluidic devices, and that HC1 could be extracted faster than H3P04 due to smaller mass transfer resistance and much stronger re- action between HCI and TOA. For the extraction of H3PO4 and KC1 solutions, the selectivity for HC1 first increased and then decreased when TOA was in excess of H3PO4 in the initial feeds, and in contrast, always increased when H3PO4 was in excess of TOA in the initial feeds. The diverse changes of selectivity for HCI along with the residence time indicate that a dynamic control of selectivity in microfluidic devices may be important and accessible for im- proving the KH2P04 conversion efficiency in extraction method.

Comparison of deep desulfurization methods in alumina production process

Several methods of deep desulfurization in alumina production process were studied, and the costs of these methods were compared. It is found that most of the S2- in sodium aluminate solution can be removed by adding sodium nitrate or hydrogen peroxide in digestion process, and in this way the effect of S2- on alumina product quality is eliminated. However, the removal efficiency of 2?32OS in sodium aluminate solution is very low by this method. Both S2- and 2?32OS in sodium aluminate solution can be removed completely by wet oxidation method in digestion process. The cost of desulfurization by wet oxidation is lower than by adding sodium nitrate or hydrogen peroxide. The results of this research reveal that wet oxidation is an economical and feasible method for the removal of sulfur in alumina production process to improve alumina quality, and provide valuable guidelines for alumina production by high-sulfur bauxite.

Alginate Encapsulation as a Preservation Method of Pitaya Fruit Juice （Stenocereus spp.）

Alginate is a widely used polymer matrix in food industry since it allows formation of spherical, soft, and strong membranes adequate for encapsulation of a large amount of products, including food. The flow rate of alginate solutions and the permeability of the capsules were evaluated within an acidic-low acidic pH range and different alginate concentrations. In solutions adjusted at different pH （3.0 to 7.0） with concentrations of alginate of 0.8, 1.0, and 1.2% w/v, flow rates at 20 ℃ were 6.95 to 10.00, 4.54-5.35, and 2.60-2.80 mL sl, respectively. Permeability of the capsules was evaluated in terms of the diffusion of H＋ions （expressed as pH） and soluble solids （~Brix）. Meanwhile both diffusions were minor at 4.0 〈 pH 〈 7.0 and were significantly superior at more acidic pH （P 〈 0.05）, alginate concentration did not present significant effect. Yellow, purple, and red juices from Stenocereus spp. fruits （pitayas） were encapsulated using 1.0% of alginate and stored with isotonic solution （3 mL g^-1） at 4 ℃ in the dark. The capsules were spherical with diameter between 4.59 and 470 mm, weight from 82.60 to 97.50 rag, and volume of 0.075-0.098 mL. Pigment （total betalains content） diffusion reached equilibrium at 24 h of storage, at which point retentions of total betalains in the yellow, purple, and red capsules were 87.79, 96.13, and 85.13%, respectively. Also, changes in the color of the capsules were observed during storage.

Role of mitogen- and stress-activated kinases in inflammatory arthritis

Lysophosphatidic acid （LPA） is a pleiotropic lipid med-iator that promotes motility, survival, and the synthesis of chemokines/cytokines in human fbroblast-like syno-viocytes （FLS） from patients with rheumatoid arthritis. LPA activates several proteins within the mitogen acti-vated protein （MAP） kinase signaling network, including extracellular signal-regulated kinases （ERK） 1/2 and p38 MAP kinase （MAPK）. Upon docking to mitogen and stress-activated kinases （MSKs）, ERK1/2 and p38 MAPK phosphorylate serine and threonine residues within its C-terminal domain and cause autophosphorylation of MSKs. Activated MSKs can then directly phosphorylate cAMP response element-binding protein （CREB） at Ser133 in FLS. Phosphorylation of CREB by MSKs is essential for the production of pro-inflammatory and anti-infammatory cytokines. However, other downstream effectors of MSK1/2 such as nuclear factor-kappa B, histone H3, and high mobility group nucleosome binding domain 1 may also regulate gene expression in immune cells involved in disease pathogenesis. MSKs are master regulators of cell function that integrate signals induced by growth factors, proinflammatory cytokines, and cellular stresses, as well as those induced by LPA.