共查询到17条相似文献,搜索用时 109 毫秒
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本文以大量实验数据为依据,用理论和实验结合的方式,归纳、论证了干扰物对空白、检出限的影响。 相似文献
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试剂空白校正是光谱分析中亟待解决的问题之一,提出采用一种新的以零吸收波长试剂的空白吸光度为分母的光谱多波长K系数校正空白影响的新方法,首先通过模拟实验数据并应用模拟纯光谱与校正光谱间的误差确定选择零波长,继而运用各波长K系数从实验混合光谱中通过△A=A-K.A校正试剂空白得到真实光谱,最后以Zn-PAR,Cu-TAPP及Hg-H2Dz3个典型体系空白校正为例说明本法的初步应用。 相似文献
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光电直读光谱分析中的空白校正法及应用 总被引:4,自引:0,他引:4
运用空白校正校正在光电直读光谱分析中因试样类型,组织结构,成分含量,仪器波动和基体效应等因素造成的系统误差,本文对空白校正的方法原理,操作要点,实现过程及应用也作了介绍。 相似文献
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本文提出一个计算被测元素百分含量的公式。它确切、直观地反映了被测元素的浓度在标准系列浓度范围,超过甚至大大超过高、低标浓度时试液与空白的关系。我们引入关系常数n使三种关系在公式中直观地体现出来。 相似文献
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X荧光光谱仪器发展迅速,应用领域广泛,由于其能够快速、准确分析样品,不需要繁琐的前处理和耗材,已能替代部分传统AAS, ICP和ICP-MS等分析仪器。如何准确地评价其应用性能,以更便捷地使用,常用检出限作为评价方法的重要指标。检出限计算方法和形式较多,一般等于空白样品的3倍标准偏差,在实际样品分析时,小于检出限的含量,不可检出;大于检出限、小于定量限的含量,可定性分析;大于定量限的含量,可准确分析。XRF计算方法和分析领域中常用的检出限计算方法不同,传统分析方法测量值符合正态分布,是连续分布;XRF测量值属于泊松分布,是离散分布,只有在计数足够大的时候才能接近正态分布。在实际分析中,往往不会耗时去积累足够大的计数。介绍了7种检出限的计算方法:X荧光泊松分布法、 K倍标准偏差法、线性校准法、 RSD法、 SD直线外推法、环境监测分析法、海洋监测规范法。以X荧光重金属检测仪的检测数据为例,测试6个大米粉参考样品中Pb, As和Cd元素含量,详细对比了各方法的计算过程和考虑因素。由于实际样品中很难找到绝对不含被测元素的空白,以近似空白样品替代。泊松分布方法测试次数最少,测2次即可快速准确计... 相似文献
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Abstract A novel microcombustion technique for carbon isotopic analysis of nanogram amounts of carbon in non-volatile materials based on isotope ratio monitoring (irm) mass spectrometry is described. Liquid or solid samples placed in a quartz sleeve are combusted at 1000°C in a continuous stream of helium and oxygen. CO2 removed from the carrier gas stream by cryogenic trapping is transferred onto a GC column. Following GC separation, the CO2 is transferred via an open split to the ion source of a gas isotope ratio mass spectrometer. Reproducibility for samples >25 nmol carbon is <1‰. Problems associated with blanks from various sources and with reproducible deposition of small sample amounts led to variable accuracy, which was dependent on the compound class being analysed. Minimum sample size was in the range from 5 to 10 nmol carbon. Measurements of dissolved organic carbon (DOC) of groundwater from Germany yielded consistent values of δ13C = -28.8‰. 相似文献
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A. A. Ilyukhina V. I. Kolpakov A. L. Galinovskii A. V. Khakhalin 《Moscow University Physics Bulletin》2018,73(4):441-446
We substantiate the recommendations for improving the efficiency of hydro- and hydroabrasive cutting of the honeycomb structures that are widely used in aircraft and rockets, obtained by numerical solving of the spatial dynamic problem with allowance for the physico-mechanical and kinematic parameters of a high-speed jet, the physico-mechanical and structural parameters of the treated honeycomb structure, and the parameters of the technological treatment (feeding and the impact angle of the jet with the face surface of the blanks). A physico-mathematical model and a method of numerical analysis of the process have been developed. The influence of the above parameters on the quality of the surfaces of the treated blanks is illustrated. The results of the calculations are compared with the experimental data. 相似文献
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We use stochastic resonance to measure weak transmittance amplitudes that are below the instrumental detection limit. Gaussian noise is added to the subthreshold (chopped) transmittance signal T(t) before detection by a crossing detector that uses a dc reference signal B>0. Without noise, no measurement is possible because T(t)相似文献
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Photoacoustic spectroscopy for trace gas detection with cryogenic and room-temperature continuous-wave quantum cascade lasers 总被引:1,自引:0,他引:1
Virginie Zeninari Agnès Grossel Lilian Joly Thomas Decarpenterie Bruno Grouiez Bernard Bonno Bertrand Parvitte 《Central European Journal of Physics》2010,8(2):194-201
The main characteristics that a sensor must possess for trace gas detection and pollution monitoring are high sensitivity,
high selectivity and the capability to perform in situ measurements. The photacoustic Helmholtz sensor developed in Reims,
used in conjunction with powerful Quantum Cascade Lasers (QCLs), fulfils all these requirements. The best cell response is
# 1200 V W−1 cm and the corresponding ultimate sensitivity is j 3.3 × 10−10 W cm−11 Hz−11/2. This efficient sensor is used with mid-infrared QCLs from Alpes Lasers to reach the strong fundamental absorption bands
of some atmospheric gases. A first cryogenic QCL emitting at 7.9 μm demonstrates the detection of methane in air with a detection
limit of 3 ppb. A detection limit of 20 ppb of NO in air is demonstrated using another cryogenic QCL emitting in the 5.4 μm
region. Real in-situ measurements can be achieved only with room-temperature QCLs. A room-temperature QCL emitting in the
7.9 μm region demonstrates the simultaneous detection of methane and nitrous oxide in air (17 and 7 ppb detection limit, respectively).
All these reliable measurements allow the estimated detection limit for various atmospheric gases using quantum cascade lasers
to be obtained. Each gas absorbing in the infrared may be detected at a detection limit in the ppb or low-ppb range. 相似文献
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Detection Limit of Glucose Concentration with Near-InfraredAbsorption and Scattering Spectroscopy
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Theoretical analyses and Monte Carlo simulation are performed to investigate the detection limit of glucose concentration with near-infrared spectroscopy. The relation between detection limitation of glucose concentration and source-detector separation is derived. Monte Carlo simulation performed with a skin-layered model shows that the ratio of effective photons from the target layer could excess 50% by selecting proper source-detector separation, and that the detection limit of glucose concentration approaches to 0.28mM, which satisfies the requirement of food and drug administration for noninvasive glucose sensing. 相似文献
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