Movement measurement with a grating interferometer using sinusoidal phase-modulation

Movements of a surface profile are measured with a two-grating interferometer using sinusoidal phase-modulation. Since sinusoidal phase-modulating (SPM) interferometry can record a phase change due to the movement of an object in the interference signal, the SPM interferometer is suitable for measuring the movement of the object. Some experiments show that the two-grating interferometer can measure a sinusoidal vibration with amplitude of several tens of microns and a step movement with a magnitude of several microns.     

三维荧光光谱法结合交替三线性分解算法同时分辨及定量测定秦皮中的秦皮甲素和秦皮乙素成分

用三维荧光分析结合交替三线性分解算法对秦皮中药成分进行定性定量分析,为直接测定秦皮甲素和秦皮乙素提供了一种快速简洁的方法。相关系数r分别为1．000和0．998。多次测定结果的相对误差分别为2．01％和2．21％。     

Photon-Counting Phase-Modulation Fluorometer

We propose a phase-modulation fluorometer that is applicable to a very weak fluorescence intensity level. In order to counter the single-photon event situation, we have introduced a combination of a time-to-amplitude converter and a pulse height analyzer (PHA) to the fluorometer, the combination of which is usually used in the single-photon correlation method to measure fluorescence decay waveforms with pulsed excitation. In the proposed fluorometer, a sinusoidal response waveform that is shifted in phase over the reference one is obtained statistically as a histogram in the PHA memory, and then the fluorescence lifetime can be calculated by the same procedure as the conventional analog phase-modulation method. The excitation light source used was a current-modulated ultraviolet light-emitting diode, whose center wavelength was 370 nm and whose spectral bandwidth was 10 nm. Fluorescence lifetimes of 17.5 ns and 5.7 ns obtained for 10 ppb quinine sulfate in 0.1 N H₂SO₄ and for 10 ppb rhodamine 6G in ethanol, respectively, agreed well with those reported in the literature. In passing, we report that the fluorescence lifetime of benzo[a]pyrene in dichloromethane is 14.6 ns, which is known as one of the carcinogenic, environmental-pollution materials.This paper was originally presented at the 2001 International Conference (2nd Joint OSJ-SPIE Conference) on Optical Engineering for Sensing and Nanotechnology, ICOSN 2001 which was held June 6#x2013;8, 2001 at the Pacifico-Yokohama Conference Center, Yokohama, Japan.     

催化动力学光度法测定痕量铜的研究进展

综述了近年来国内外催化动力学光度法测定痕量铜的进展情况。对催化氧化动力学光度法、催化还原动力学光度法、催化荧光光度法、阻抑动力学光度法等几个类别，从反应介质、灵敏度、线性范围等方面介绍了对不同反应体系的研究情况，并对催化动力学光度法测定痕量铜的发展趋势做出预测。     

Chelometric Titration of Trace Amounts of Metal Ions Employing Instrumentally Measured Fluorometric Endpoints

Abstract

Trace amounts of metal ions which form stable complexes with EDTA at pH 4.0 have been titrated using morin as a fluorometric indicator. Back ticration of excess EDTA with Ga(III) and instrumental endpoint detection were employed for the determination of ions which are not normally determined by fluorometric methods. The continuous monitoring of the change in the fluorescence intensity throughout a deration also allowed mixtures of Ga(III) and In(III) to be determined when TTHA and EDTA were employed as double titrants.     

Studies on the Toluidine Blue Dimer as a Fluorescence Probe for Protein Assays

Abstract

A spectrofluorometric method was developed for the determination of total serum protein by exploring toluidine blue (TB) as the fluorescence probe. The fluorescence intensity of TB at 648 nm was significantly quenched in the presence of sodium dodecylbenzene sulfonate (SDBS) by forming a dimer of the dye, which can afterwards reconvert to monomer when proteins were added accompanied by the recovery of the fluorescence. This might be attributed to the modulated transferring of the dimer‐monomer equilibrium of TB in the anionic surfactant caused by the addition of protein. A linear calibration graph was obtained in the range of 0.5–50 mg/l BSA, with a detection limit of 0.15 mg/l and a RSD of 1.3% (n=11, 5.0 mg/l BSA). Total proteins in human serums were analyzed by using the present procedure and the results agreed well with those obtained by the Biuret method.     

On the Stability of Isoindole-Type Fluorophores Derived from O-Phthalaldehyde,Primary Amino Compounds and Thiols

Abstract

o-Phthalaldehyde (OPA), a primary amino compound and a thiol react to produce a ternary isoindole-type fluorophore. The effect of the structure of the constituent amino compound on the chemical stability of isoindole fluorophores was investigated. The amino compounds with steric hindrance around the -NH₂ group such as L-tryptophan and L-Dopa exhibited a marked stabilization effect on the isoindole fluorophores. By using OPA and L-typtophan as reagents, a procedure was established for the fluorometric determination of thiols which permitted the determination of 2 nmol of L-cysteine (CySH). The possible mechanism for the instability of isoindole accelerated by increasing concentration of OPA was also discussed.     

同步荧光法同时测定水溶解态的蒽和芘

利用PAHs具有高的荧光量子产率,同步荧光法具有快速、灵敏、选择性较好的优点,建立了同时测定水溶液中溶解态蒽和芘的方法。所建方法测定蒽和芘的线性范围分别为1.0×10-8~2.0×10-7mol/L和5.0×10-9~3.5×10-7mol/L,检出限分别为1.69×10-9mol/L、8.42×10-10mol/L,相对标准偏差分别为2.90%、2.34%(n=5)。运用所建方法尝试了自来水样品的测定。     

薄层-胶束荧光法测定北豆根中的两种生物碱

本文选用恰当的薄层色谱体系,对秦巴山区所产北豆根中的生物碱类物质粉防已碱和青藤碱进行分离,并用胶束荧光法进行定量,按本文设计的实验方案测出粉防已碱和青藤碱的含量分别为9.94×10~(-3),1.07×10~(-2)g/g,检出限分别为3.5×10~(-12),5.85×10~(-11)g/mL,回收率分别为93.5%,97.2%.     

流动注射在线萃取荧光法测定痕量阴离子表面活性剂

报道了痕量阴离子表面活性剂的流动注射在线萃取荧光分析方法．该方法测定的线性范围为 ０．０１～０． ２０ ｍｇ／Ｌ；进样频率为 ２０样／ｈ．应用本法测定了水样中痕量阴离子表面活性剂，得到了满意的结果．