Supercritical fluid extraction and gas chromatography analysis of arsenic species from solid matrices

A method in combination with derivatization-supercritical fluid extraction(SFE) and gas chromatography(GC) for the speciation and quantitative determination of dimethylarsinate(DMA), monomethylarsonate(MMA) and inorganic arsenic in solid matrices was investigated. Thioglycolic acid methyl ester(TGM) and thioglycolic acid ethyl ester(TGE) were evaluated as derivatization reagents. The effects of pressure, temperature, flow rate of supercritical CO_2, extraction time, modifier and microemulsion on the efficiency of extraction were systematically investigated. The procedure was applied to the analysis of real soil and sediment samples. Results showed that TGE was more effective for arsenic speciation as a derivatization reagent. Modifying supercritical CO_2 with methanol can greatly improve the extraction efficiency. Further, the addition of microemulsion containing surfactant Triton X-100 can further enhance recoveries of arsenic species. The optimum extraction conditions were 100 ℃, 30 MPa, 10 min static and 25 min dynamic extraction with 5%(v/v) methanol, and surfactant modified supercritical CO_2. Detection limits in solid matrices were 0.15, 0.3 and 1.2 mg/kg for DMA, MMA and inorganic arsenic,respectively. The method was validated by the recovery data. The resulting method was fast, easy to perform and selective in the extraction and detection of various arsenic species in solid matrices.     

三（3－苯基－4－苯甲酰基异噁唑酮－5）－乙醇－水合铕三元配合物的合成、表征及晶体结构

合成了三（３－苯基－４－苯甲酰基异唑酮－５）－乙醇－水合铕的配合物。有关鉴定和元素分析结果表明：该配合物的分子式为［Ｅｕ（ＰＢＩ）３（Ｃ２Ｈ５ＯＨ）（Ｈ２Ｏ）］·Ｈ２Ｏ，其中３－苯基－４－苯甲酰基异唑酮－５简记为ＨＰＢＩ，是一种新型高酸度的β－双酮。用Ｘ射线单晶衍射法测定了［Ｅｕ（ＰＢＩ）３（Ｃ２Ｈ５ＯＨ）（Ｈ２Ｏ）］·Ｈ２Ｏ的晶体结构，结果表明，该晶体属单斜晶系，Ｐ２１／ａ空间群，晶胞参数：ａ＝１．５５８６（９）ｎｍ，ｂ＝２．１２９７（７）ｎｍ，ｃ＝１．６０４（１）ｎｍ，β＝１１７．９７（５）°，Ｖ＝４．７０３（９）ｎｍ３，Ｚ＝４．中心离子铕为八配位，其配位多面体为畸变的双帽三棱柱。配位的８个氧原子分别来自３个ＰＢＩ配体中的６个氧、１个溶剂化乙醇分子中的氧和１个水分子中的氧，Ｅｕ—Ｏ配位键平均键长０．２３９１（４）ｎｍ。晶体结构中还存在１个未配位的水分子。该水分子、配位水分子、乙醇分子与配体ＰＢＩ中的Ｎ原子之间均存在强的氢键作用。同一ＰＢＩ基团内配位氧之间的平均距离为０．２８０８ｎｍ。     

(硫代)磷酰脲衍生物的研究——Ⅴ.N-[O,O-二烷基(硫代)磷酰基]-N＇-(4-氯苯甲酰基)脲的合成和性质

Nikonorov等人曾报道N＇-烃基磷酰脲类化合物具有良好的除草活性,但对N＇-芳酰基磷酰脲类衍生物尚未见报道。前文曾报道此类化合物的先导母体化合物[(RO)_2P(X)-NHCONHCOC_6H_5]的合成和对乙酰胆碱酯酶(AChE)的抑制活性。为了进一步研究这类化     

Synthesis and Structure of 5-Amino-6-(4-fluorophenylamino)-3-methylthio-1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one

The title compound (C18H15FN6OS) has been synthesized and its crystal structure was determined by X-ray analysis. The crystal belongs to monoclinic system, space group P21/n with a = 13.983(10), b = 7.337(5), c = 16.702(12) (A), α = 90, β = 98.277(12), γ = 90°, V = 1696(2)(A)3, Z = 4, Dc= 1.498 g/cm3, Mr = 382.42,μ = 0.224 mm-1, F(000) = 792, the final R = 0.0362 and wR = 0.0878 for 2579 observed reflections with I ＞ 2σ(Ⅰ). In the title compound, the atoms of C(1),C(2), C(3), C(4), C(5), N(1), N(2), N(3), N(4), N(5), N(6), O(1) and S(1) form a fully delocalized system with the average deviation of 0.0307(A). There exists a part of electron delocalization over the planes of Ⅰ (pyrazolo[3,4-d]pyrimidin-4-one moiety), Ⅱ (phenyl moiety) and Ⅲ (p-fluorophenylamine moiety). In the molecule, intermolecular hydrogen bonds between N(6)-H(6)…O(1)and C( 15)-H( 15)…O( 1 ) are observed.