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131.
偏最小二乘光度法同时测定多种酚的研究及应用 总被引:6,自引:0,他引:6
利用Cu(Ⅱ)吡啶能与酚形成稳定的三元配合物的特点,研究了Cu(Ⅱ)-吡啶-酚三元显色新体系,并以偏最小二乘法建立模型预测,同时测定了模拟水样和环境水样中的对苯二酚、间苯二酚、邻苯三酚和对硝基苯酚,取得满意效果。 相似文献
132.
133.
Barnes JH Schilling GD Stone SF Sperline RP Denton MB Young ET Barinaga CJ Koppenaal DW Hieftje GM 《Analytical and bioanalytical chemistry》2004,380(2):227-234
The use of a separation step, such as liquid chromatography, prior to inductively coupled plasma mass spectrometry (ICP–MS) has become a common tool for highly selective and sensitive analyses. This type of coupling has several benefits including the ability to perform speciation analysis or to remove isobaric interferences. Several limitations of conventional instruments result from the necessity to scan or pulse the mass spectrometer to obtain a complete mass spectrum. When the instrument is operated in such a non-continuous manner, duty cycle is reduced, resulting in poorer absolute limits of detection. Additionally, with scanning instruments, spectral skew can be introduced into the measurement, limiting quantitation accuracy. To address these shortcomings, a high-performance liquid chromatograph has been coupled to an ICP–MS capable of continuous sample introduction and simultaneous multimass detection. These features have been realized with a novel detector array, the focal plane camera. Instrument performance has been tested for both speciation analysis and for the elimination of isobaric interferences. Absolute limits of detection in the sub picogram to tens of picograms regime are obtainable, while the added mass dimension introduced by simultaneous detection dramatically increases chromatographic peak capacity. 相似文献
134.
一阶导数光谱K系数法同时测定硝基酚钠三组分 总被引:2,自引:0,他引:2
研究和建立了同时测定硝基酚钠混合三组份的新方法——一阶导数光谱K系数法。确定了最佳实验条件和测定波长,方法简便、快速、准确。通过对动植物细胞赋活增进剂中邻硝基酚钠、对硝基酚钠、5-硝基愈创木酚钠三组份的直接测定,其相对误差小于2%,相对标准偏差小于3%,回收率为99~103%。 相似文献
135.
Crystalline title compound (1) prepared from aqueous solution of theophylline and 1,4-diaminobutane has been structurally and thermally characterized. Both the two-step TG decomposition curve and elemental analysis of the hexagonal crystals show that it consists of theophylline and 1,4-diaminobutane in 2:1 molar ratio. Actually, presence of one type of both theophyllinate anions and 1,4-diammoniumbutane dication have been indicated by FTIR spectroscopy. The molecular structure of lattice compound (1) has been determined by single crystal X-ray diffraction, where the hydrogen positions have been obtained from differential Fourier maps. It has confirmed that the crystal is really built up from these ionic constituents bound together with an extensive net of hydrogen bonds. The coupled TG-FTIR analysis of the evolved gases has revealed that the diamine is released as a whole molecule in the first decomposition step. Clathrate 1 and the proton migration in it might serve as a structural model of solid aminophylline whose crystal structure is still unknown. 相似文献
136.
Christel Hempen 《Analytica chimica acta》2004,521(2):117-122
A detection scheme for the simultaneous evaluation of two bioassays based on fluorescence spectroscopy is presented. For the determination of hydrogen peroxide-generating enzymes or peroxidases, the non-fluorescent 4-(N-methylhydrazino)-7-nitro-2,1,3-benzooxadiazole (MNBDH) is converted to the strongly fluorescent 4-(N-methylamino)-7-nitro-2,1,3-benzooxadiazole (MNBDA). Phosphatases are detected based on the cleavage of the non-fluorescent 5-fluorosalicyl phosphate (5-FSAP) under formation of the fluorescent 5-fluorosalicylic acid (5-FSA). While excitation of the fluorophores may be carried out at the same wavelength, their emission spectra differ significantly. This allows the read-out of both assays using commercially available microplate readers without additional chemometric tools. Compared with individual assays, limits of detection are similar, and linearity of the calibration functions for both enzymes is observed over 2-3 concentration decades starting at the limit of quantification. The simultaneous determination of glucose oxidase and acid phosphatase in honey is presented as example for the application of the detection scheme. 相似文献
137.
Guodong Feng Yanfu Huan Yanbo Cao Shuhua Wang Xinghua Wang Jie Jiang Aimin Yu Qinhan Jin Hongmei Yu 《Microchemical Journal》2004,76(1-2):17
An unique miniature simultaneous microwave plasma torch (MPT) atomic emission spectrometer employing linear UV intensified charge-coupled device (ICCD) array detector has been developed and studied preliminarily. The detection limits and precisions of the spectrometer for Ag, Al, Ba, Ca, Cr, Cu, Fe, Mg, Mn, Sr and V by using different CCD exposure times have been determined. An analysis of a practical sample has been carried out. The preliminary results demonstrate that such simultaneous spectrometer has advantages of saving sample and time, especially suitable for use as detector for chromatography and in combination with flow injection systems. Taking analytical figures of merit and portability into accounts, the miniature simultaneous MPT system will have extended application areas and greater competition potential as compared with commercialized scanning MPT spectrometers. 相似文献
138.
《Electroanalysis》2003,15(17):1397-1402
A new analytical procedure for the simultaneous determination of aluminum(III) and iron(II) in two kinds of dialysis fluids (peritoneal and hemodialysis fluids) by differential pulse adsorptive stripping voltammetry (DPAdSV) is described. The voltammetric measurements were performed using, as working electrode, a stationary mercury electrode, and a platinum electrode and a Ag|AgCl|KCl(sat.) electrode as auxiliary and reference electrodes, respectively, employing acetate buffer solutions at different pH as supporting electrolyte. As complexing agents, Solochrome Violet RS, Palatine Chrome Black 6BN, Chromazurol S and Eriochrome Black T were employed. For both elements, the accuracy, expressed as relative recovery R%, was very satisfactory being in the range 94–105%, the precision as repeatability, expressed as relative standard deviation sr%, was lower than 6%, while the limits of detection were of the order of a few units of μg/L. The analytical voltammetric procedure has been validated by comparison with spectroscopic (graphite furnace atomic absorption spectroscopy, GFAAS) measurements. 相似文献
139.
Teruaki Hayakawa Shin Horiuchi Hiroshi Shimizu Tadashi Kawazoe Motoichi Ohtsu 《Journal of polymer science. Part A, Polymer chemistry》2002,40(14):2406-2414
Polystyrene‐b‐poly(1,2‐isoprene‐ran‐3,4‐isoprene) block copolymers with azobenzene side groups were synthesized by the esterification of azobenzene acid chloride with polystyrene‐b‐hydroxylated poly(1,2‐isoprene‐ran‐3,4‐isopenre) block copolymers for creating new photochromic materials. The resulting block copolymers with azobenzene side groups were characterized for structural, thermal, and morphological properties. IR and NMR spectroscopies confirmed that the polymers obtained had the expected structures. Differential scanning calorimetric measurements by heating runs clearly showed the glass transitions of polystyrene and polyisoprene main chains and two distinct first‐order transitions at temperatures of azobenzene side groups around 48 and 83 °C. The microstructure of these block copolymer films was investigated using both transmission electron microscopy (TEM) and near‐field optical microscopy (NOM). TEM images revealed typical microphase‐separated morphologies such as sphere, cylinder, and lamellar structures. The domain spacing of microphase‐separated cylindrical morphology in the NOM image agreed with that of the TEM results. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2406–2414, 2002 相似文献
140.
《Journal of separation science》2003,26(17):1509-1519
Theophylline, tolbutamide, mephenytoin, debrisoquin, and dapsone are marker substrates for CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4, respectively. A silica‐based monolithic column (Chromolith SpeedROD RP‐18e, 50×4.6 mm) was used to separate these five marker substrates of cytochrome P450 within only 84 s. Linear gradient elution was from acetonitrile‐water‐formic acid (10 : 90 : 1, v/v/v) to acetonitrile‐water‐formic acid (90 : 10 : 1, v/v/v) in 1.4 min. The flow rate was 2.5 mL/min. The retention time was 0.52 min for theophylline, 0.67 min for debrisoquin, 0.78 min for dapsone, 0.96 min for mephenytoin, and 1.13 min for tolbutamide. Detection was by tandem mass spectrometry using a PE Sciex API 3000 mass spectrometer with a Turbo‐Ionspray source in positive mode. A simple protein precipitation method was used. This method was validated over the concentration range of 5–2000 ng/mL based on the sample volume of 0.1 mL. 相似文献