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61.
Determination of Organophosphorus Pesticides in Soil by MMSPD-GC-NPD and Confirmation by GC-MS 总被引:1,自引:0,他引:1
A novel method, modified matrix solid-phase dispersion (MMSPD), has been developed for quantitative analysis of organophosphorus
pesticide residues in soil. It was based on matrix solid-phase dispersion (MSPD) and continuous liquid-solid extraction (continuous
LSE), using Florisil as sorbent and dichloromethane as the recycling solvent. Two soils with different texture and physicochemical
properties were studied to validate the method. The effect of residence time of pesticides in soil was also studied. MMSPD
was compared with MSPD and continuous LSE respectively. Determination was carried out by gas chromatography with nitrogen-phosphorus
detection (GC-NPD). The method gave recoveries ranging from 72–105% with relative standard deviations (RSDs) lower than 15%
for the pesticides studied. The limits of detection (LODs) ranged from 0.1 to 0.6 ng g−1. Two pesticide residues have been detected in real soil samples from Fujian, China, using MMSPD. The pesticides were confirmed
by gas chromatography-mass spectrometry (GC-MS) in a selected-ion monitoring (SIM) mode.
Revised: 4 and 9 April 2006 相似文献
62.
在很高的温度和适宜的生长条件下,分别采用熔盐籽晶法和高温引上法生长了高质量的YAP、NAB、KTP、LN、BBO、SBN等多元氧化物单晶,它们具有优良的物理化学性能,严格的化学比,固定的组成与结构以及较好的化学均匀性和电子束轰击下的稳定性。广泛地用于激光和非线性光学领域。我们选用这些晶体为原材料研制电子探针定量分析的标准样品。经过测量和标定,这些单晶标样符合中华人民共和国国家标准GB 4930-85(电子探针显微分析标准样品通用技术条件)的规定。含有稀土元素的标样如NAB和YAP能发出绿色荧光,是电子显微术中理想的阴极发光材料。 相似文献
63.
Da Xu Zhong Lan Gao Na Li Ke An Li Key Laboratory of Bioorganic Chemistry Molecular Engineering of Ministry of Education College of Chemistry Molecular Engineering Peking University Beijing China 《中国化学快报》2007,18(5):561-564
Ru(bpy)_(3~(2 )) electrochemiluminescence (ECL) was applied to determination of rutin. ECL intensity of Ru(bpy)_(3~(2 ))could be enhanced in the presence of rutin in basic solution on platinum electrode. At pH 9.9, light emission intensity was found to be linear with rutin in the range of 1-50 mmol/L. 相似文献
64.
Raman spectroscopic analysis of supersaturated aqueous solution of MgO.B2O3-32%MgCl2-H2O during acidification and dilution 总被引:1,自引:0,他引:1
Zhihong L Bo G Shuni L Mancheng H Shuping X 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2004,60(13):3125-3128
Raman spectra of supersaturated aqueous solution of MgO.B2O3-32%MgCl2-H2O during acidification/alkalization and dilution have been studied. The assignments of the recorded Raman shift are given. The main existing forms of polyborate anions and their interaction in borate aqueous solution have been proposed through spectroscopic analysis. The experimental results indicate that the higher concentration of cation are beneficial not only to the dissolution of boric acid but also to the polymerization of polyborate anions. The existing forms and interaction among them also depend on the concentration of boron and the pH value in solution. 相似文献
65.
66.
Hong Tao Gao Dong Mei Dai Tong Hua Li 《中国化学快报》2007,18(4):495-498
Non-negative matrix factorization(NMF)is a technique for dimensionality reduction by placing non-negativity constraints onthe matrix.Based on the PARAFAC model,NMF was extended for three-dimension data decomposition.The three-dimension non-negative matrix factorization(NMF3)algorithm,which was concise and easy to implement,was given in this paper.The NMF3algorithm implementation was based on elements but not on vectors.It could decompose a data array directly without unfolding,which was not similar to that the traditional algorithms do.It has been applied to the simulated data array decomposition andobtained reasonable results.It showed that NMF3 could be introduced for curve resolution in chemometrics. 相似文献
67.
低硫可膨胀石墨的制备 总被引:18,自引:0,他引:18
低硫可膨胀石墨的制备宋克敏,路文义,高淑英,阎秋燕(河北教育学院石家庄050091)关键词低硫可膨胀石墨,制备,过氧化氢,硫酸柔性石墨具有耐高温、耐酸碱、抗拉、抗压、抗辐射、回弹性等优良性能,被广泛应用于化工、机械、肮天、原子能等领域。但其原材料可膨... 相似文献
68.
Dong-Dong Zhou Jun Wang Pin Chen Yangyong He Jun-Xi Wu Sen Gao Zhihao Zhong Yunfei Du Dingyong Zhong Jie-Peng Zhang 《Chemical science》2021,12(4):1272
Rational manipulation of supramolecular structures on surfaces is of great importance and challenging. We show that imidazole-based hydrogen-bonded networks on a metal surface can transform into an isostructural coordination network for facile tuning of the pore size and guest recognition behaviours. Deposition of triangular-shaped benzotrisimidazole (H3btim) molecules on Au(111)/Ag(111) surfaces gives honeycomb networks linked by double N–H⋯N hydrogen bonds. While the H3btim hydrogen-bonded networks on Au(111) evaporate above 453 K, those on Ag(111) transform into isostructural [Ag3(btim)] coordination networks based on double N–Ag–N bonds at 423 K, by virtue of the unconventional metal–acid replacement reaction (Ag reduces H+). The transformation expands the pore diameter of the honeycomb networks from 3.8 Å to 6.9 Å, giving remarkably different host–guest recognition behaviours for fullerene and ferrocene molecules based on the size compatibility mechanism.A hydrogen-bonded network on a Ag(111) surface can transform into an isostructural Ag(i) coordination network, giving drastically different host–guest recognition behaviours. 相似文献
69.
The binary phase diagram of KNO3-KClO3 is studied by means of differential scanning calorimetry (DSC) and high-temperature X-ray diffraction. The limited solid solutions, K(NO3)1−x(ClO3)x (0<x<0.20) and K(NO3)1−x(ClO3)x (0.90<x<1.0), were formed in the KNO3-based solid solutions and KClO3-based solid solutions phase, respectively. For KNO3-based solid solutions, KNO3 ferroelectric phase can be stable from 423 to 223 K as a result of substituting of NO3 by ClO3-radicals. The temperatures for solidus and liquidus have been determined based on limited solid solutions. Two models, Henrian solution and regular solution theory for KNO3-based (α) phase and KClO3-based (β) phase, respectively, are employed to reproduce solidus and liquidus of the phase diagram. The results are in good agreement with the DSC data. The thermodynamic properties for α and β solid solutions have been derived from an optimization procedure using the experimental data. The calculated phase diagram and optimized thermodynamic parameters are thermodynamically self-consistent. 相似文献
70.