原子吸收自吸背景校正中杂散光的研究Ⅰ——杂散光的性质及其对背景校正性能的影响

在自吸背景校正中不被样品基体吸收的杂散光有不同于氘灯和塞曼背景校正的特殊性。用截止溶液法检验了杂散光的存在,并用重铬酸钾溶液分子吸收模拟背景吸收的方法研究了杂散光的影响。源于空心阴极灯光源的杂散光在样品束(常规脉冲低电流)和参比束(窄脉冲高电流)中的比率有很大的差异,前者比后者更高。这种差异是自吸背景校正误差的重要来源,在高背景校正时引起的误差不容忽视。文章还对杂散光比率与灯电流、光能量和光谱带宽等方面的关系进行了研究。结果表明,杂散光比率与灯电流大小有很大关系,灯电流大,杂散光比率小,但杂散光比率随灯电流的变化与被检测的分析线能量无直接关系;杂散光比率随着光谱带宽的减小而降低,其性质类同于连续光谱。     

The Zeeman Splitting of Aluminium Monochloride Molecular Absorption Bands as the Possible Interference in Atomic Absorption Spectrometry

The molecular absorption was measured using a sharp line irradiation source together with the Zeeman background correction. The measured absorption was caused by aluminium chloride that was measured using lead hollow cathode lamp. Some kind of Zeeman splitting has been found in the case of studied molecular absorption bands having sharp lines. The absorptions measured were very unstable and noisy. However there was found some relationship between the measured absorption and the amounts of chlorine.     

高频等离子光谱—动态背景校正法分析催化剂中的钯和铂

本文介绍了应用ICP-动态背景校正法测定催化剂中钯和铂的方法。并分析了几个主要元素的光谱干扰情况。     

High-Resolution Continuum Source Atomic and Molecular Absorption Spectrometry—A Review

Abstract

The present article gives an overview over the historic development, the instrumentation, the special features, and the applications of high-resolution continuum source atomic and molecular absorption spectrometry. The most obvious advantage is the need for only one single lamp for all elements and wavelengths, compared to one lamp for each analyte, as is necessary in line source atomic absorption spectrometry. The visibility of the spectral environment of the analytical line at high resolution greatly helps in method development and to avoid spectral interferences. The advanced simultaneous background correction automatically eliminates lamp flicker noise and continuous background absorption. Fine-structured background absorption may be removed using a reference spectrum and a least-squares algorithm. Because any wavelength between 190 nm and 900 nm can be accessed, the same equipment can be used for molecular absorption spectrometry, making possible the determination of non-metals, such as phosphorus, sulfur, and the halogens. Although commercial equipment for this technique has only been available for a few years, the technique has been accepted extremely well, and the number of applications that have been published using this technique has already reached an impressive number.     

悬浮液进样自吸扣背景石墨炉原子吸收光谱法测定高纯氧化铝中铜、铁和钠含量

采用悬浮液-自吸扣背景石墨炉原子吸收法测定了高纯氧化铝中痕量元素铜、铁、钠含量.实验对灰化温度、原子化温度和自吸扣背景灯电流等石墨炉原子吸收工作条件等进行了优化,确定了最佳测定条件.样品测试采用标准水溶液进行校正,方法准确性采用氧化铝AKP-30在高温高压和浓硫酸密闭条件下溶解样品进样分析测定结果与文献报道的其他测定方...     

一种用于一次谐波背景消除与基线校正的新型方法

针对可调谐半导体激光吸收光谱一次谐波信号中具有背景信号及较大的基线信号,提出一种新型的背景消除与基线校正的处理方法.分析了一次谐波背景中的激光器相关强度调制信号,电子学噪声和光学干涉条纹,采用无吸收谱线区域检测谐波方法消除背景信号.给出了激光器不同工作温度时的电流和强度之间的关系曲线,由此设计出消除背景后剩余基线的校正方法.文中给出了背景搜索方法的原理以及LabView软件流程图.设计了检测氟化氢气体的实验系统,根据谱线选取原则确定吸收谱线为1312.59 nm,设置激光器的工作温度为27.0?C,对应的背景温度为30.2?C.一次谐波信号经过背景消除和基线校正后,信号的畸变得到明显改善,基线得到校正,验证了该方法在激光器其他工作温度(26.7—27.2)是有效的,并对HF气体浓度精度的改善进行了定量分析,为一次谐波信号的后续处理提供了方便.     

Estimation of signal backgrounds on multivariate loadings improves model generation in face of complex variation in backgrounds and constituents

The present study is designed to understand further implications of using multivariate loadings for the correction of background signal, which has previously been shown to be highly reproducible even for very low quality signals. Singular value decomposition (SVD)‐based background correction was compared with the traditional per‐signal paradigm for a biomedical dataset to generate qualitative and quantitative models. The qualitative effect on a principal component analysis model and the quantitative effect on a partial least square regression model were assessed for these background correction methods. The chosen quantitative parameter was the concentration of a pathologically relevant protein modification, pentosidine. Of the approaches tested, the SVD‐based paradigm provided the regression model with the highest correlations, highest accuracy (lowest standard error of prediction) and repeatability (lowest sampling error). Contrasted against the traditional approaches, it was determined that the improved accuracy and repeatability of the SVD‐based approach arises from its ability to simultaneously handle very complex background shapes alongside the complex variation in biochemical species that resulted in Raman signals with incompatible baseline regions. A better understanding of the interaction of SVD‐based baseline correction, and data will give the reader more insight into the potential applicability of the procedure for other datasets. Copyright © 2012 John Wiley & Sons, Ltd.     

An intelligent background‐correction algorithm for highly fluorescent samples in Raman spectroscopy

Fluorescent background is a major problem in recoding the Raman spectra of many samples, which swamps or obscures the Raman signals. The background should be suppressed in order to perform further qualitative or quantitative analysis of the spectra. For this purpose, an intelligent background‐correction algorithm is developed, which simulates manual background‐correction procedure intelligently. It basically consists of three aspects: (1) accurate peak position detection in the Raman spectrum by continuous wavelet transform (CWT) with the Mexican Hat wavelet as the mother wavelet; (2) peak‐width estimation by signal‐to‐noise ratio (SNR) enhancing derivative calculation based on CWT but with the Haar wavelet as the mother wavelet; and (3) background fitting using penalized least squares with binary masks. This algorithm does not require any preprocessing step for transforming the spectrum into the wavelet space and can suppress the fluorescent background of Raman spectra intelligently and validly. The algorithm is implemented in R language and available as open source software ( http://code.google.com/p/baselinewavelet ). Copyright © 2009 John Wiley & Sons, Ltd.     

Photolytic interference affecting two-photon laser-induced fluorescence detection of atomic oxygen in hydrocarbon flames

This study reports on photochemical interferences affecting atomic oxygen detection using two-photon laser-induced fluorescence at 226 nm. In contrast to previous studies in which molecular oxygen was proven to be the relevant photochemical precursor molecule in a hydrogen-fueled flame, the present investigations were carried out in a laminar diffusion flame of methane and air. The most significant interferences were found at the fuel side of the flame in the absence of molecular oxygen, and vibrationally excited carbon dioxide was identified as the most probable precursor molecule for the photochemical production of oxygen atoms. Received: 11 December 2002 / Revised version: 10 March 2003 / Published online: 16 April 2003 RID="*" ID="*"Corresponding author. Fax: +1-925/294-2595, E-mail: tbsette@sandia.gov     

高分辨连续光源原子吸收光谱法测定植物中的硫

硫元素在富燃的乙炔/空气火焰可形成CS双原子分子,在某些特定的波长下,这些CS分子吸收谱线具有原子吸收的轮廓和一定的吸收强度。文章主要研究利用高分辨连续光源原子吸收光谱法,通过测定硫元素在富燃-乙炔/空气火焰条件下形成的CS双原子分子的吸光度值,从而测定植物样品中的硫元素含量。实验对乙炔-空气比例和燃烧器高度等仪器条件进行了优化;实验研究了五种有机溶剂对CS分子吸收产生的影响情况、其他共存元素的光谱干扰和化学干扰以及不同的消解酸种类对测定结果的影响。在优化的条件下,硫在CS 257.961 nm的检出限为14 mg·L-1。通过对植物标准物质中硫含量的测定比对和精密度实验证明, 利用连续光源原子吸收光谱法,在富燃-乙炔/空气焰条件下以CS分子测定植物样品中的硫元素是一种简单、快速、有效的方法。     

Radiation trapping in atomic absorption spectroscopy at lead determination in different matricies

The determination of lead by flame atomic absorption analysis in the presence of Sn and Fe atoms and different matrices such as OH and SO₃ was investigated with the objective of understanding the spectral interference processes at the analytical lines 283.31 nm for a wide range of concentration.The radiation trapping factor was interpreted and evaluated assuming Voigt distribution of the atomic and rotational lines in the flame. The radiation trapping factor was increased by increasing the number density (plasma of the absorbing medium is optically thick). In plasma, there is a certain point of equilibrium between the trapping and the escaping of radiation, which is relevant to 50% of absorption.The spectral background interference can cause a variation of the number density at equilibrium point as a result of the degree of overlap with the analytical line.The spectral background interference can be easily avoided by using another resonance absorption line for the analysis. The chemical modification of the matrix is applied to minimize the interference effect. Nitric acid, ammonium nitrate and magnesium nitrate are most commonly recommended as matrix modifiers.     

FAAS直接法测定环境和生物试样中Zn、Pb和Cd

本文系统研究了海水、土壤、沉积物和生物中Cd、Pb和Zn用火焰原子吸收直接法测定时的干扰与背景校正。由于这些物质基体中含有大量Al、Na、K、Ca、Mg、Fe等元素,在火焰中形成MX、MO和MOH分子光谱与分析元素线重叠,经背景校正后可获得更准确的结果和更好的回收率,对检出限和精密度均有改善。     

紫外分光光度法测定废水中的乙基黄原酸钾

乙基黄原酸钾在301nm处有最大吸收峰.在酸性条件下,乙基黄原酸钾能迅速分解,同时其吸收峰消失.根据此特性,可采用紫外分光光度法测定生产废水中乙基黄原酸钾的含量.以待测废水样作背景校正,可以有效的消除干扰.该方法的检出限为0.01mg/L,方法的线性范围为0.04-18mg/L.水样测定的相对标准偏差为1.63%.加标...     

松香中金属元素含量的测定

采用甲基异丁基甲酮溶解松香,用0.1mol/L盐酸作为水相反萃取其中的重金属,用火焰原子吸收光谱法对铁、镍、铜、铅、锌的含量进行测定。并且探讨了该方法搅拌时间对测定结果的影响及多次测定的重现性。该方法铁、镍、铜、铅、锌的平均回收率为90.9%—95.5%,RSD为1.8%—5.3%,检出限为0.01—0.25mg/L。     

火焰原子吸收光谱法测定火山矿泉水中的铁

采用火焰原子吸收光谱法测定天然火山矿泉水样中铁的含量.经测定火山附近有两处矿泉水中含有较高浓度的铁.方法线性范围为0.3-3.0mg/L,精密度和准确度较好.检出限为0.070mg/L.     

火焰原子吸收光谱法测定废水中的重金属离子

采用火焰原子吸收光谱法测定了废水中的重金属离子,测定结果为:Cu,2.89mg/L;Mn,1.08mg/L;Pb,0.98mg/L;Zn,0.96mg/L;Fe,0.95mg/L;Cr,0.10mg/L;Cd,0.08mg/L。相对标准偏差分别为:2.3%,1.9%,2.0%,1.8%,1.5%,2.3%,1.4%。     

原子吸收和发射法测定重质油中钠含量

在乙炔－空气火焰中，用吸收和发射测定原油，渣油等重质油品中的钠含量，认为用发射法既可节省元素灯，又能提高测量精度。吸收和发射法的特征浓度分别为：０．０１５ｍｇ／Ｌ和０．００９ｍｇ／Ｌ。     

A Solid Phase Extraction Application of Hybrid Nano B_2O_3/ZrO_2 for Separation and Determination of Trace Indium in Environmental Samples

Hybrid nanomaterials have attracted considerable interest in environmental science, analytical chemistry and atomic spectroscopy. In the present study, a column solid phase extractioo procedure was developed for the separation and preconcentration of indium in various matrixes by using hybrid nanomaterial B₂O₃/ZrO₂ (HNMBZ). Various experimental and analytical parameters such as sample solution pH, sample solution volume, flow rate of sample solution and eluent, volume and concentration of eluent aod amount of HNMBZ, effect of common matrix ions and capacity of sorbent were investigated. The adsorbed metal ions on HNMBZ were eluted with 6 mL of 1 mol·L-1 HNO₃ solutions and their concentrations were determined by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS). Under the optimized conditions, detection limits for indium for 3 pixels and 5 pixels were found as 0.20 and 0.16 μg·L-1, respectively. The accuracy of the procedure was checked by spiked water samples. The developed procedure was successfully applied to real samples for the separation and determination of indium.     

火焰原子吸收法测定钢铁中钴时的背景吸收及消除

对于背景校正装置的原子吸收分光光度计,用火焰原子吸收法测定钴时,由于铁等有背景吸收（指铁的背景通过吸收池以后的背景,称为背景吸收）,故无法用标准加入法测定钢铁中低含量钴。本文对测钴时的背景吸收及铁的干扰做了详细的研究,用金２４２．８ｎｍ谱线做为测钴时背景吸收校正线,可完全扣除背景吸收。用标准加入法测定了钢及高温合金中低含量钴。     

非完全消解-火焰原子吸收光谱法测定虾皮中的铁、铜、锌和锰

用非完全消解法处理虾皮样品,即在低温下用浓硝酸-过氧化氢(3+1)混合酸消解样品,再用乳化剂OP溶解未消解的油脂而配制成无色透明的溶液,将此溶液用火焰原子吸收光谱法测定其中铁、铜、锌和锰元素的含量。建立了快速测定虾皮中微量元素的火焰原子吸收光谱法。对样品处理条件、混合酸中杂质及共存OP的干扰进行了实验,铁、铜、锌和锰的检出限(3S/k)分别为0.021、0.047、0.008、0.026m g.L-1。该法测定虾皮中铁、铜、锌和锰的含量,所得结果与灰化法测定结果一致。