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81.
Sapelnikova S Dock E Solná R Skládal P Ruzgas T Emnéus J 《Analytical and bioanalytical chemistry》2003,376(7):1098-1103
Screen-printing technology for electrode fabrication enables construction of amperometric devices suitable for combination of several enzyme electrodes. To develop a biosensor array for characterisation of wastewaters, tyrosinase and horseradish peroxidase (HRP) or cholinesterase-modified electrodes were combined on the same array. The behaviour of the tyrosinase-modified electrode in the presence of hydrogen peroxide (required co-substrate for the HRP-modified electrode) and acetylthiocholine chloride (required co-substrate for cholinesterase) was studied. Performance of bi-enzyme biosensor arrays in the batch mode and in the flow-injection system are discussed. 相似文献
82.
Summary The possibilities and limitation of automated solute identification via UV/VIS spectroscopy in HPLC are demonstrated and applications in toxicologic analysis are described. A standard isocratic system is used. The influence of various chromatographic parameters on retention time is shown. A retention time window of ±15% is required. In addition to retention time, derived spectral data are calculated (minima and maxima of derivatives, area counts under standardized spectral ranges, absorption at various wavelength) and used for positive solute identification. It is possible to identify solutes with a high degree of certainty in urine and plasma if their concentration is at least 10 ppm. 相似文献
83.
84.
Summary The effect of drying conditions on the preservation of chlorophyll pigments in mint and basil have been investigated in order to determine the effects of drying temperature and whether or not there was a prior blanching.Pigments extracted from fresh and dried samples were analyzed by reversed phase high performance liquid chromatography coupled to a photodiode array detector; isocratic separation was performed on a Zorbax ODS C18 column.The purity of the chromatographic peaks of chlorophylls and breakdown products was investigated. The visible spectra of standard samples of chlorophylls and pheophytins were compared, using least squares normalization with those of peaks from the extracts of fresh and dried mint and basil. The study has shown that chlorophylls were better preserved when drying was preceded by a short blanching; if samples were not blanched before drying, the degradation of chlorophylls a and b was best prevented by drying at low temperatures. 相似文献
85.
86.
Xianpeng Yin Hao Dong Shiqiang Wang Yun Liang Ning Gao Wanlin Zhang Li Tian Fuwei Sun Guangtao Li 《中国化学快报》2019,30(1):179-182
In this work, large area gold-nanoparticle-cluster pillar array with a gold mirror as high-performance SERS substrate was facilely fabricated by combined use of nanosphere lithography and self-assembly approach. 相似文献
87.
A rapid and inexpensive method for simultaneous quantification of terbumeton (TER), and its major potential metabolites (TED;
terbumeton-desethyl, TOH; terbumeton-2-hydroxy and TID; terbumeton-deisopropyl) in soil bulk water (SBW) samples is proposed.
The analytical method involves extraction–concentration from SBW samples using a graphitized carbon black (GCB) cartridge
followed by their separation–detection by reversed-phase high-performance liquid chromatography analysis using a C18 column and a diode array detector. A mobile phase of acetonitrile−0.005 mol L−1 phosphate buffer (pH 7.0) (35:65, v/v) at a flow rate of 0.8 mL min−1 in isocratic elution mode has been used. After optimization of the extraction and separation conditions, this method can be
used for the simultaneous determination of investigated compounds in the range of the international limits of 0.1 μg L−1. For TER the detection limit was 0.009 μg L−1 and it was 0.100, 0.550, and 0.480 μg L−1 for TED, TOH, and TID, respectively. The recoveries of TER, TED, TOH, and TID from SBW samples, measured at three levels of
concentration range, were found to be between 48.0 and 102.0%. The intra-day precision measured by relative standard deviation
(RSD) was always lower than 9.0%. 相似文献
88.
Sokkalingam Punidha 《Tetrahedron》2004,60(38):8437-8444
A new method has been developed to synthesize 21,23-dithiaporphyrins having one pyridyl group at the meso position. The method required easily available unknown precursors and the condensation resulted in mono meso-pyridyl 21,23-dithiaporphyrins as single products in 8-11% yield. Two of the three mono meso-pyridyl N2S2 porphyrins were used to synthesize non-covalent unsymmetrical porphyrin dimers containing one N2S2 and one N4 porphyrin cores. 相似文献
89.
G. Durand S. Chiron V. Bouvot D. Barceló 《International journal of environmental analytical chemistry》2013,93(1-2):31-42
Abstract C-18 Empore extraction disks were used for the isolation and trace enrichment of different groups of pesticides from river water and artificial sea water at concentration levels of 0.2, 5 and 20 μg/l [chlorotriazines, (atrazine and simazine), their dealkylated metabolites, (deethyl- and deisopropylatrazine), organophosphorus (parathion-ethyl), phenylurea (linuron), anilide (propanil), carbamate (aldicarb and carbofuran) and carbamate transformation products (aldicarb sulfoxide, aldicarb sulfone and 3-hydroxy-7-phenol carbofuran]. The extraction disks allowed high flow rates thus 51 samples could be processed within 2h. 30 min. For most of the pesticides the recoveries, as determined by liquid chromatography with diode array detection (LC-DAD), varied from 74 up to 125% with coefficients of variations (CV) of 5-10%, whereas for the carbamate transformation products the recoveries were in the range of 30-35% having a CV of 17-21%. At spiking level of 0.2 μg/l the dealkylated triazine metabolites and the carbamate transformation products were not detected at all. 相似文献
90.
The traditional microphone configuration used to measure room impulse responses (IRs) according to ISO 3382:2009 is an omnidirectional and figure-8 microphone pair. IRs measurements were taken in a 2500-seat auditorium to determine how the results from a spherical microphone array (an mh acoustics Eigenmike-em32) compare to those from the traditional microphone setup (a Brüel & Kjær Type-4192 omnidirectional microphone and a Sennheiser MKH30 figure-8 microphone). Measurements were obtained at six receiver locations, with three repetitions each in order to first evaluate repeatability. The metrics considered in this study were: reverberation time (T30), early decay time (EDT), clarity index (C80), strength (G), lateral energy fraction (JLF) and late lateral energy level (LJ). Before calculating these quantities, the IRs were filtered to equalize the frequency response of the microphones and sound source. For the spherical array measurements, the omnidirectional (monopole) and figure-8 (dipole) patterns were extracted using beamforming. In terms of repeatability, the average standard deviation of the three measurements at each receiver location averaged across all metrics, receivers, and octave bands was found to be 0.01 just noticeable differences (JNDs). The analysis comparing the measurements from the two microphone configurations yielded differences which were less than 1 JND for the majority of metrics, with a few exceptions of EDT and C80 slightly above 1 JND. Based on this case study, these results indicate that spherical microphone arrays can be used to obtain valid room IR measurements, which will allow for the development of new metrics utilizing the higher spatial resolution made possible with spherical arrays. 相似文献