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991.
动态冷原子吸收法快速测定地球化学样品中微量汞 总被引:3,自引:0,他引:3
本文介绍了动态冷原子吸收法快速测定地球化学样品中微量汞的方法。本文研究采用了新型的汞蒸气发生器,并对气泡的干扰进行了研究。线性范围为0.2-12ng/mL,标准回收率为97%-106%,相对标准偏差为3.6%,相关系数为0.9997,试验结果表明此方法简便、快速、准确。 相似文献
992.
Imdad Ullah Mohammadzai Tomoko Ashiuchi Satoshi Tsukahara Yasuaki Okamoto Terufumi Fujiwara 《中国化学会会志》2005,52(5):1037-1042
A simple and fast flow method for the trace level determination of p‐toluidine, 2‐methyl‐5‐nitroaniline, and 2,4‐dinitroaniline in aqueous samples is reported. These amino/nitroaromatics are related to trinitrotoluene (TNT) and appear during the degradation process of the explosive. The chemical principles of ion‐pair formation and liquid‐liquid extraction are applied: In aqueous acidic medium, the protonated analyte [HA]+ makes an ion‐pair with the tetrachloroaurate(III) ion, followed by on‐line ion‐pair extraction into the dichloromethane carrier used. After membrane separation, the CH2Cl2 containing the ion‐pair, [HA]+[AuCl4]−, is mixed with the reversed micellar luminescent reagent of luminol (in 0.3 M Na2CO3) prepared from cetyl‐trimethylammonium chloride in CH2Cl2‐cyclohexane and the [AuCl4−‐luminol chemiluminescence (CL) output is recorded. The detection limits (S/N> 3) are: p‐toluidine, 1.0 × 10−4M; 2‐methyl‐5‐nitroaniline, 1.0 × 10−7 M; 2,4‐dinitroaniline, 1.0 × 10−7 M, while the calibration curves are linear between 1.0 × 10−4 — 1.0 × 10−2 M for all the compounds. Although spectral studies indicated the formation and extraction of a very small amount of the ion‐pair species, the reversed micellar‐mediated CL detection system provides an alternative procedure for the determination of degradation products of the explosive TNT in environmental aqueous samples. 相似文献
993.
We present a new method for the measurement of the phase of ultrashort optical pulses with high spectral resolution. This
employs an interferometer with a monochromator in one arm. Two detectors operating in single photon and two-photon absorption
regimes monitor the output from the interferometer. Comparison of the signals from the two detectors gives a measurement of
the phase of the light pulse. The principles underpinning this technique are discussed and the experimental application to
picosecond pulses is demonstrated. 相似文献
994.
Z.X. Chao L.K. Seah V.M. Murukeshan U.S. Dinish C.S. Tan 《Optics & Laser Technology》2007,39(4):864-870
In this paper, a novel configuration of an integrated phase-resolved (PR) fingerprint fluorescence imaging system is proposed and implemented. In this integrated PR imaging system, a current modulated 402 nm dual diode laser is proposed to be the light source, to obtain both high laser power and easy modulability. To estimate the lifetime resolution of this PR imaging system, a novel method of using distance-selective suppression of fluorescence signals from two identical fluorescing samples is proposed. Detailed theoretical and experimental analyses are presented. The experimental results demonstrate that this integrated PR imaging system has a lifetime resolution of 0.1 ns. Fingerprint detection experiments are also carried out using this system with latent fingerprints deposited on substrates of aluminum foil and currency. 相似文献
995.
火焰原子吸收光谱法测定固体废弃物磷石膏中微量铜和铅 总被引:2,自引:0,他引:2
利用浓硝酸和浓盐酸消解磷石膏固体样品,选择了这两种酸的最佳用最,建立一种磷石膏样品处理方法。研究了应用火焰原子吸收光谱法直接吸取含盐量高的样品溶液,测定其中CU和pb的可行性。一份样品进行7次测定,结果表明,CU和Pb的RSD分别为2.6%和2.0%,加标回收率分别为92.88%一105.04%和91.20%-103.60%。 相似文献
996.
997.
Summary A method based on a linear model enabling the efficient determination of the ionization constants (K
a) of saccharides by capillary zone electrophoresis with amperometric detection has been demonstrated. TheK
a values obtained from the plots of the reciprocal effective mobility against the inverse concentration of sodium hydroxide
were in agreement with literature values. 相似文献
998.
Summary A method was developed for the determination of nitrobenzoic acids and nitrophenols as well as of diaminoaromatics and was
applied to the analysis of water samples from the former ammunition plant at Elsnig (Saxony, Germany).
The procedure is based on a preseparation into a neutral, an acidic and a basic fraction by multi-step extraction at different
pH values followed by HPLC analysis with UV and electrochemical detectors, coupled in series.
Applying optimized enrichment conditions, all investigated compounds were extracted from spiked distilled water with recoveries
>80% and variation coefficients <7%. Similar results were obtained with spiked ground water samples.
After enrichment, all compounds can be analysed by HPLC with UV detection at concentrations below 100 ngL−1. The electrochemical detector (ELCD) allowed a selective and sensitive detection of the nitrophenols and especially of the
diaminoaromatics and, therefore, provides, some advantages in the analysis of real samples.
Presented at the 21st ISC held in Stuttgart, Germany, 15th–20th September, 1996 相似文献
999.
用毛细管离子分析 (CIA)法 ,采用 10mmol·L- 1咪唑为背景电解质 ,4 0 %甲醇为选择性改性剂 ,在 pH 2 .5、分离电压为 2 5kV、柱温为 2 2℃的电泳条件下 ,采用间接紫外检测 (2 14nm ) ,在5min内测定了人发中铝 ,方法简便、快速、灵敏度高、重现性好、测定成本低 相似文献
1000.