X-ray photoelectron spectroscopic study of the mechanism of palladium matrix modification in the electrothermal atomic absorption spectrometric determination of lead and bismuth

The mechanism of palladium matrix modification is studied for the determination of lead and bismuth by graphite-furnace atomic absorption spectrometry. The binding energies of the charring products for lead and bismuth in the presence or absence of palladium obtained at the initial stage of atomization were measured. The binding energies indicated the formation of PbPd and BiPd bonds, thus explaining the increase in appearance temperatures of lead and bismuth in the presence of palladium.     

反相高效液相色谱中复杂体系二元多台阶梯度分离条件快速优化方法

提出了一种反相高效液相色谱中二元多台阶梯度分离条件快速优化方法。通过数次线性梯度初始实验，求得溶质的保留方程。在此基础上，利用重叠分离区域图（OSRM）方法，快速求得复杂样品的最佳多台阶梯度分离条件。该方法只需要几个小时就可以完成对复杂样品分离条件的优化，并通过对中药川芎提取物的分离加以验证，获得了较好的预测精度和分离效果。     

Improvement of Pulse Amperometric Detection Integrated Automated Flow Injection Analysis of Ethylenethiourea Determination

Improvement of pulse amperometric detection (PAD) method is demonstrated in determination of ethylenethiourea (imidazolidine‐2‐thione, ETU). The anodic detection of ETU will produce polymeric film on an electrode leading to an inactive electrode surface. Here, the PAD method was used to remove the polymeric film formed on the electrode surface between ETU detection. Further, the scheme was integrated with automated flow injection analysis (AFIA) for determining ETU. The operational parameters of PAD in the AFIA system were discussed thoroughly. The analytical characteristics of the system were evaluated at optimum conditions. The linear range of calibration plot was between 20 to 300 μM (the correlative coefficient, r = 0.999) and the detection limit was 0.9 μM (S/N = 3). The relative standard deviations of detection of 50 μM ETU were 0.82% with and 9.07% without PAD scheme. The results indicate the system is a very promising tool for ETU determination. Finally, the matrix effects of two water samples that were collected from a campus and a farm show good recoveries of 92% and 96%.     

A preliminary study of isopropyl alcohol matrix effect and correction in ICP-MS

Isopropyl alcohol matrix effect was found to be element specific by using the defined matrix effect factor in ICP-MS,which could not be corrected by using the conventional internal reference method.Unlike the conventional internal reference method,the presented method allows for the analyte to behave differently from the internal reference under the influence of the matrix.     

The Condensation of Aromatic Aldehydes with Acidic Methylene Compounds in Water

The condensation of aromatic aldehydes with acidic methylene compounds such as malononitrile, methyl cyanoacetate, cyanoacetamide, 5,5-dimethyl-1,3-cyclohexanedione,bartbituric acid and 2-thiobarbituric acid proceeded very efficiently in water in the presence of triethylbenzylammonium chloride (TEBA) and the products were isolated simply by filtration.     

Two New Steroidal Glycosides from Liriope muscari

Liriope muscari (Decn.) Bailey (Liliaceae) is a folk medicinal plant used as a substitute of Ophiopogon japonicus (Thunb.) Ker-Gawl., mainly distributing in Quanzhou, Fujian Province, China1. Previously, we reported the isolation and identification of two…     

“手”望相助，志虑忠“醇”

Through three stories about alcohol antiseptics, "hand" messengers, characters of the article find the best choice of alcohol, and method of application. This article introduces proper ways to use alcohol antiseptics in daily life from the following three aspects. The ethanol and propanol can be used, the best concentration for daily use is 70%, and the optimal use of alcohols is considered under different circumstances.     

枸杞子中红色素的提取及稳定性

枸杞子中红色素的提取及稳定性伍明，王杰，闪春霞，任仲皎，宋锡瑾，詹国庆（中南民族学院化学系武汉４３００７４）关键词枸杞，色素，液泛提取法枸杞子为茄科枸杞属植物的果实，具有补肾养肝，润肺明目以及调节机体免疫力，抑制肿瘤生长和细胞突变，延缓衰老及抗脂肪肝...