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51.
Perla Xochitl Rojas‐Gonzlez María Pilar Brandi‐Blanco Alfonso Castieiras Duane Choquesillo‐Lazarte Josefa María Gonzlez‐Prez Juan Nicls‐Gutirrez 《无机化学与普通化学杂志》2005,631(11):2156-2160
The crystal of the N‐isopropyl‐iminodiacetic acid ( 1 ) consists of a 3D H‐bonded framework where the zwitterion (H2iPIDA±) is intra‐stabilized by one N+‐H···O interaction and both carboxyl are half‐protonated and involved in linear O‐H···O inter‐molecular bridges of 2.46 Å. The mixed‐ligand complexes [Cu(iPIDA)(H2?im)(H2O)]·3H2O ( 2 ) and [Cu(iPIDA)(H5?im)]n ( 3 ) have also been synthesized and studied by thermal, spectral, magnetic and X‐ray diffraction methods. Both complexes exhibit a square base pyramidal coordination, type 4+1. Compound 3 is the less steric hindered 'remote' isomer, with H5?im instead of H4?im. 相似文献
52.
Roger Fuoco M. Perla Colombini Alessio Ceccarini Carlo Abete 《Microchemical Journal》1996,54(4):384-390
The presence and the distribution of polychlorobiphenyls (PCBs) in Antarctic environmental components and the effect of the seasonal formation/melting process of pack ice on the pollution level of seawater were investigated. Seawater, marine, and lake sediment and soil samples were collected in a large area of the Ross Sea and Victoria Land during the 1988–1989, 1989–1990, 1990–1991, and 1991–1992 Italian expeditions. The results obtained highlighted a low and quite homogeneous PCB contamination of the studied area. Surface seawater samples from Gerlache Inlet and Wood Bay showed a typical PCB concentration of 130 pg/liter, and an increase after pack ice melting of about 30–40%. Marine sediment, lake sediment, and soil samples showed normalized mean PCB contents of 150, 240, and 130 (pg/g)/(m2/cm3), respectively. 相似文献
53.
Analytical quality control procedures for ensuring reliable data in the determination of PCBs in environmental matrices are described. Several extraction procedures of PCBs from sediment samples are critically compared and recovery and reproducibility for PCBs determination in sediment and cod liver oil samples are evaluated. Extraction by 1:1n-hexane/acetone mixture in an ultrasonic bath and by supercritical fluids generally give a quantitative recovery and a coefficient of variation lower than 15%, while extraction by a Soxhlet system does not give such good results and requires much longer extraction times. Certified reference materials available from three international organizations, namely the Standards, Measurements and Testing programme of the European Union, the USA National Institute of Standards and Technology and the National Research Council of Canada were used. Finally, the on-going European Union QUASIMEME programme aimed at improving the analytical quality of marine pollution monitoring measurements of European laboratories is addressed. 相似文献
54.
Bonaduce I Brecoulaki H Colombini MP Lluveras A Restivo V Ribechini E 《Journal of chromatography. A》2007,1175(2):275-282
This paper presents an analytical GC-MS procedure to study the chemical composition of plant gums, determining aldoses and uronic acids in one step. The procedure is based on the silylation of aldoses and uronic acids, released from plant gums by microwave assisted hydrolysis, and previously converted into the corresponding diethyl-dithioacetals and diethyl-dithioacetal lactones. Using this method only one peak for each compound is obtained, thus providing simple and highly reproducible chromatograms. The analytical procedure was optimised using reference samples of raw plant gums (arabic, karaya, ghatti, guar, locust bean and tragacanth, cherry, plum and peach gums), commercial watercolours and paint layers prepared according to ancient recipes at the Opificio delle Pietre Dure of Florence (Italy). To identify gum media in samples of unknown composition, a decisional schema for the gum identification and the principal component analysis of the relative sugar percentage contents were employed. The procedure was used to study samples collected from wall paintings from Macedonian tombs (4th-3rd centuries bc) and from the Mycenaean "Palace of Nestor" (13th century bc) in Pylos, Greece. The presence of carbohydrates was ascertained and plant gum binders (fruit and a mixture of tragacanth and fruit tree gums) were identified in some of the samples. 相似文献
55.
Using a one-pot Sharpless asymmetric epoxidation/regioselective epoxide ring-opening as a key step, the protecting-group-free total synthesis of goniothalesdiol A was accomplished in only three steps starting from commercially available trans-cinnamaldehyde in 55.1% overall yield. In 6 previously reported total syntheses, 6–11 steps were required. 相似文献
56.
A rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the estimation of amlodipine in human plasma 总被引:1,自引:0,他引:1
Bhatt J Singh S Subbaiah G Shah B Kambli S Ameta S 《Biomedical chromatography : BMC》2007,21(2):169-175
A rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the estimation of amlodipine in human plasma. Amlodipine was extracted from human plasma by using a solid-phase extraction technique. Imipramine was used as the internal standard. A Hypersil BDS C18 column provided chromatographic separation of analytes followed by detection with mass spectrometry. The method involves a rapid solid-phase extraction from plasma, simple isocratic chromatography conditions and mass spectrometric detection that enables detection at sub-nanogram levels. The proposed method has been validated for a linear range of 0.1-10.0 ng/mL with correlation coefficient >or=0.9990. The intrarun and interrun precision and accuracy were within 10.0%. The overall recovery for amlodipine was 63.67%. Total run time was 3.2 min only. 相似文献
57.
Josefina Prez-Arantegui Gemma Cepri Erika Ribechini Ilaria Degano Maria Perla Colombini Juan Paz-Peralta Esperanza Ortiz-Palomar 《Trends in analytical chemistry : TRAC》2009,28(8):1019-1028
Archaeological cosmetics, as well as revealing ancient knowledge, contain a complex mixture of very different organic and inorganic components with diverse properties. Most information on the preparation of ancient cosmetics comes from classical texts. However, although analysis of products contained in archaeological objects has recently identified some ingredients, there is still little known about how the cosmetics were prepared.Using a multi-analytical approach, we studied the chemical composition of two Roman pink make-ups that were preserved on the surface of a Roman bronze cosmetic tool and in a glass unguentarium. The results revealed that both make-ups were colored by madder lake but prepared in two different ways and with two completely different matrices (i.e. scented oils in the first case and gypsum in the second) highlighting that the make-ups had been prepared thoroughly, the ingredients carefully selected and their properties and possibilities for good cosmetic use had been understood. 相似文献
58.
Marianne Odlyha Jeannette J. Lucejko Anna Lluveras-Tenorio Francesca di Girolamo Stephen Hudziak Adam Strange Alexandra Bridarolli Laurent Bozec Maria Perla Colombini 《Molecules (Basel, Switzerland)》2022,27(19)
The aim of the current work is twofold: to demonstrate the application of in situ non-invasive imaging by portable atomic force microscopy (AFM) on the surfaces of a violin and to integrate compositional and mechanical analysis at the nano scale level on model samples of varnished wood. These samples were prepared according to traditional recipes by an Italian lute-maker family well practised in the art. Samples of oil and spirit-based varnishes on maple wood, naturally and accelerated light aged, were studied. AFM was used to measure the nanomechanical properties of the model samples and established that the spirit-based varnish was stiffer than the oil-based. Synchrotron radiation micro- Fourier Transform Infra-red analysis of the layer structure revealed that stiffer spirit-based varnish showed less penetration into the wood than the oil-based. Further PeakForce Quantitative Nanomechanical Mapping (QNM) demonstrated a difference in adhesion values between the oil- and spirit-based samples. 相似文献
59.
A green synthesis of 1,2,3-triazolyl-pyridine hybrids and evaluation of their antibacterial activity