用智能波长校正的扫描式电感耦合等离子体光谱仪测定高炉渣中7种…

本文利用作者所在实验室发现的，光栅单色仪的出射光谱线峰漂移与温度变化以及波长变化间的非线性函数关系，以及在此基础上所开发的扫描式ＩＣＰ－ＡＥＳ光谱仪的智能波长校正装置，取代传统的局部恒温系统，测定了高炉渣中的Ｓｉ，Ｃａ，Ｍｇ，Ｍｎ，Ｆｅ，Ｔｉ，Ａｌ７种元素成份，测定结果与标样的鉴定值一致，测量的相对标准偏差（ＲＳＤ）为１．ｘ％。智能波长校正装置的波长校正结果与谱线峰描迹结果的比较表明，该智能波长校     

用智能波长校正的扫描式电感耦合等离子体光谱仪测定高炉渣中7种元素成份

本文利用作者所在实验室发现的，光栅单色仪的出射光谱线峰漂移与温度变化以及波长变化间的非线性函数关系，以及在此基础上所开发的扫描式ICP－AES光谱仪的智能波长校正装置，取代传统的局部恒温系统，测定了高炉位中的Si，Ca．Mg，Mn，Fe，Ti，Al7种元素成份。测定结果与标样的鉴定值一致，测量的相对标准偏差（RSD）为1．X％。智能波长校正装置的波长校正结果与话线峰描迹结果的比较表明，该智能彼长校正装置是有效的，具有省时、安全、结构简单的特点，有广泛的应用前景。     

读者园地

问:分析仪器的分辨率如何表示?江苏读者———王平答:1.光谱仪的分辨率能将两紧邻的谱线准确分辨的能力称为光谱仪的分辨率(resolu-tion),系指两条可分辨谱线波长的平均值(λ)与其波长差(Δλ)的比值:R =λ/Δλ　　上面所说的“可分辨”是指相邻两谱线中的一条谱线的极大恰落在另一谱线极小的位置(见图1)。图1　可分辨的两紧邻谱线示意图(Rayleigh准则)Fig .1　Spectra showing the resolution如果仪器采用棱镜作为色散元件,则仪器的分辨率尚与棱镜的分辨率有关,即与棱镜的数目、棱镜的底边长及棱镜材料有关。如果采用光栅作为色散元件,…     

电感耦合等离子体原子发射光谱法中Kalman滤波法解析重叠谱线的研究

考察了Kalman滤波技术校正ICP-AES中谱线重叠干扰的潜力。以新息序列的平均平方和为评价函数优化扫描光谱的峰位, 消除扫描过程中可能产生的波长定位误差, 从而保证滤波结果的准确性, 并使实际检出限显著改善。在中等分辨率光谱仪和扫描步长为1.5pm的条件下, 滤波器能有效地分辨峰间距只有4.8pm且峰形基本相同的重叠线对。对峰间距为9.8pm的重叠线时, 当线背比低至0.05左右时仍能获得满意结果。连续背景用理论描述, 因而样品溶液和纯组分溶液的光谱扫描无需扣除溶剂空白。     

电感耦合等离子体原子发射光谱法中Kalman滤波法解析重叠谱线的研究

考察了Kalman滤波技术校正ICP-AES中谱线重叠干扰的潜力.以新息序列的平均平方和为评价函数优化扫描光谱的峰位,消除扫描过程中可能产生的波长定位误差,从而保证滤波结果的准确性,并使实际检出限显著改善.在中等分辨率光谱仪和扫描步长为1.5pm的条件下,滤波器能有效地分辨峰间距只有4.8pm且峰形基本相同的重叠线对.对峰间距为9.8pm的重叠线对,当线背比低至0.05左右时仍能获得满意结果.连续背景用理论描述,因而样品溶液和纯组分溶液的光谱扫描无需扣除溶剂空白.     

因子分析-电感耦合等离子体原子发射光谱分析中的峰位优化及光谱干扰校正

将目标因子分析用于电感耦合等离子体原子发射光谱分析(ICP-AES)对高纯氧化铥中稀土杂质的测定及光谱重叠干扰校正.数据矩阵由纯光谱矢量、混合物光谱矢量及模型背景矢量构成.提出利用各目标矢量的真误差的平方和为评价函数优化扫描光谱峰位,从而消除扫描式ICP光谱仪发射光谱线的峰位移动给测定带来的影响.     

Kalman滤波技术校正电感耦合等离子体原子发射光谱分析中严重重叠的谱线干扰

针对ICP-AES中严重重叠谱线干扰的校正, 研究了若干因素对Kalman滤波器性能的影响。减小扫描步长可以增强Kalman滤波法解析重叠谱线的能力。当重叠线轮廓基本相同且扫描窗口内干扰元素只有一条谱线时, Kalman滤波法能分辨的重叠线对的最小峰间距为扫描步长的2～3倍。扫描窗口内较多的干扰元素谱线和重叠线对轮廓的显著差异有利于Kalman滤波器正确识别分析信号和干扰信号, 可以利用这两个因素有效地分辨峰间距很小甚至完全重叠的谱线。     

Kalman滤波技术校正电感耦合等离子体原子发射光谱分析中严重重叠的谱线干扰

针对ICP-AES中严重重叠谱线干扰的校正,研究了若干因素对Kalman滤波器性能的影响.减小扫描步长可以增强Kalman滤波法解析重叠谱线的能力.当重叠线对轮廓基本相同且扫描窗口内干扰元素只有一条谱线时,Kalman滤波法能分辨的重叠线对的最小峰间距为扫描步长的2～3倍.扫描窗口内较多的干扰元素谱线和重叠线对轮廓的显著差异有利于Kalman滤波器正确识别分析信号和干扰信号,可以利用这两个因素有效地分辨峰间距很小甚至完全重叠的谱线.     

酸性络蓝K双波长信号系数光度法测定钙镁

基于在氢氧化钠溶液中,钙、镁均与酸性络蓝K(ACBK)形成暗红色配合物,提出了测定钙和镁的双波长信号系数光度法.该法不仅消除了钙、镁之间的吸收干扰,且消除了一定量的共存离子的干扰.利用褪色法与生色法的吸光度之和作为信号吸光度,使方法的灵敏度大为提高.测定钙、镁总量时,分别用钙、镁吸收曲线正峰与负峰上的等吸收波长470.5 nm(λPa)及559.5 nm(λNa)处测定吸光度APa和ANa,求得总量的信号系数fs为2.439.于λPa470.5 nm处测得任一浓度钙、镁试液的吸光度APa′,其信号吸光度As=fsAλPa′.测定镁时,以试剂ACBK褪色对钙配合物生色的完全相消干扰的波长539 nm(Pa)作为测定波长,负峰波长583 nm为Na.按相同方法测得镁的信号系数fs为4.148.     

极谱曲线的背景扣除

提出一种借助微机准确、可靠扣除背景的运算方法,方法的拟合函数由背景函数B(E)=a/E+b+cE+dE~2和极谱峰函数(极谱峰电流方程与修正的高斯函数结合)加和构成,利用非线性最小二乘法参数估计,即可从实测的极谱曲线求得法拉第峰电流、峰电位和半峰宽度,而毋需空白溶液的数据,此法已应用于交流极谱和示差脉冲极谱。     

Rapid determination of chromium in natural waters by chemiluminescence with a centrifugal fast analyzer.

A secondary target tube excited x-ray fluorescence apparatus was compared with a conventional sequential wavelength dispersive spectrometer. Representative samples from the lead industry, an agglomerate for the lead production and a typical air particulate sample collected on cellulose filter were used in the comparison.The following factors were considered: resolving power, spectral interferences, intensity and peak-to-background ratio, sensitivity, reproducibility and precision. The energy dispersive method is advantageous for the multi-element analysis with limited precision of thin samples of environmental composition.     

A study of the medium voltage and high voltage controlled waveform spark sources for the spectrometric analysis of aluminium alloys

A medium voltage and a high voltage controlled waveform spark source were investigated as light sources for the analysis of aluminium alloys in an argon atmosphere using a sequential spectrometer. Burn-off curves are given for all six elements investigated and a scanning electron microscope was used to study the discharge areas on the samples. It was found that the argon purity was critical and that for the spectral lines used the high voltage source generally yielded better precision and stability.     

SPECTRAL ANALYSES OF LOW LEVEL CHEMILUMINESCENCE OF A SHORT LIFETIME USING A HIGHLY SENSITIVE POLYCHROMATIC SPECTROMETER INCORPORATING A TWO DIMENSIONAL PHOTON-COUNTING TYPE DETECTOR

Abstract— Spectral analyses of low level chemiluminescence were carried out by using a newly developed polychromatic spectrometer in which a diffracted photon emission was detected simultaneously using a two dimensional photon-counting device. The spectrometer was sensitive in the 400–800 nm wavelength range. Low level chemiluminescence generated in a 1 nM luminol solution could be detected as a spectrum, showing a peak at 430 nm. Short lifetime photon emission from singlet oxygen showed only two peaks at around 630 and 700 nm in this highly time-resolved spectroscopy. Lipid peroxidation of linoleic acid by the lipoxygenase emitted a low intensity peak centered at 440 nm, but singlet oxygen emission arising from the decomposition of lipid peroxide was not observed. An injured cotyledon of a soybean seedling gave a broad emission centered at 725 nm in the absence of hydrogen peroxide, while in its presence a different emission peak appeared at a shorter wavelength (515 nm). Oxygenated, fluorescent components in the soybean seedling may be the emitting species. Singlet oxygen and triplet carbonyl groups were shown to be unlikely sources of the emission.     

Direct Combination of a High Performance Liquid Chromatograph and a Circular Dichroism Spectrometer for Separation and Structural Analysis of Proteins

Abstract

Basic studies of the combined system of a high performance liquid chromatograph (HPLC) and a circular dichroism (CD) spectrometer for separation and analysis of proteins are described. The HPLC-CD measurement of standard protein mixture was easily carried out by using a micro flow-cell device with a beam condenser and with a thin cell of a 1 mm-optical path. The effluent was firstly monitored at 280 nm by using an UV detector and subsequently monitored at 220 nm by using a CD spectrometer. The CD spectrum at each chromatographic peak by CD was measured in the wavelength region of 250–195 nm by a stopped flow method.     

High-performance liquid chromatography and LC-ESI-MS method for the identification and quantification of two biologically active isomeric coumarinolignoids cleomiscosin A and cleomiscosin B in different extracts of Cleome viscosa

A rapid, sensitive and simple reverse-phase high-performance liquid chromatographic-electrospray ionization-mass spectrometry method for simultaneous determination of cleomiscosin A and cleomiscosin B has been developed and validated. The isomeric coumarinolignoids cleomiscosin A (1) and cleomiscosin B (2) were separated on a Waters symmetry C(18) column with a solvent system composed of acetonitrile-methanol (1:2) and acetic acid-water (0.5:99.5) in a gradient elution mode. The absorption at 326 nm was chosen as the measuring wavelength in which resolution and baseline separation of compounds 1 and 2 could be obtained. The identity of the two isomeric compounds 1 and 2 in the samples were determined on a triple quadrupole mass spectrometer with ESI interface operating in the positive mode. Calibration curves were linear (r(2) > 0.993) over the concentration range 20-200 microg/mL for cleomiscosin A and 10-200 microg/mL for cleomiscosin B with acceptable accuracy and precision, respectively. The intra-day and inter-day precision were 1.13 and 0.82% for cleomiscosin A and 1.78 and 1.28% for cleomiscosin B, respectively. The validated method was successfully applied for the analysis of the above two compounds in different extracts of Cleome viscosa.     

Performance evaluation of a rapid-scanning quadrupole mass spectrometer in the comprehensive two-dimensional gas chromatography analysis of pesticides in water

The performance of a novel rapid-scanning (20,000 amu/s) quadrupole mass spectrometer (qMS) has been evaluated in the comprehensive 2-D gas chromatography (GC×GC) analysis of pesticides contained in water. Analyte extraction was performed by using direct solid-phase microextraction (SPME). The MS system was operated using a rather wide m/z 50-450 mass range and a 33 Hz spectral production rate, a frequency which was found sufficient for reliable quantification. The qMS performance was evaluated considering: (i) number of data points per peak, (ii) mass spectral quality, (iii) extent of peak skewing, and (iv) consistency of retention times. Seven-point calibration curves (external calibration) were constructed for 28 pesticides over the limit of quantification range of 100 μg/L (1, 5, 10, 25, 50, and 100 μg/L). The solid-phase microextraction-GC×GC-qMS method was validated by calculating limits of detection and quantification, intraday peak area precision, accuracy, and intraday retention-time precision. A series of tap water samples were subjected to analysis, fortunately giving negative results.     

涤纶织物热定型后动态力学行为

利用Rhcovibron DDV-II-EA型动态粘弹谱仪测试了PET平纹布在不同温度热定型后的布样及其经、纬纱的动态力学性质。发现布及其纱的动态力学-温度谱与原纤维的截然不同。在[Ε]-T 曲线上出现[Ε]峰,[Ε]_max值随织物热定型温度的增高呈指数下降,峰位向高温移动。同时在Ε’’-T曲线上出现双损耗模量峰,相应的松弛转变活化能相差半个数量级。初步分析认为,与织布过程及随后的织物热定型有关。     

Diode laser spectroscopy of ammonia and ethylene overtones

Some overtone absorption lines of ammonia and ethylene have been examined by using a tunable diode laser (TDL) spectrometer in the region around 12,650 and 11,800 cm(-1), respectively. The spectrometer sources are commercially available double heterostructure InGaAlAs and AlGaAs TDLs operating in the "free-running" mode. The high resolving power ( approximately 10(7) ) of the spectrometer permitted the detection and the study of the line positions of such molecules with a precision better than 0.01 cm(-1). In order to maximize the signal to noise ratio and to extract the necessary informations either on the line width and on the line position for the detected molecular resonances, the wavelength modulation spectroscopy (WMS) along with the second harmonic detection techniques have been applied. For this purpose, the fitting procedure took into account the instrumental effects and the amplitude modulation (AM) always associated with the frequency modulation (FM) of these type of sources. This technique permitted also the measurement of the collisional-broadening and -shifting coefficients by different buffer gases at room temperature.     

Strong anion‐exchange liquid chromatography coupled with isotope ratio mass spectrometry using a Liquiface interface

The introduction of liquid chromatography coupled with isotope ratio mass spectrometry (LC/IRMS) as an analytical tool for the measurement of isotope ratios in non‐volatile analytes has somewhat simplified the analytical cycle from sample collection to analysis mainly due to the avoidance of the extensive sample processing and derivatisation that were necessary for gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Here we test the performance of coupling strong anion exchange to IRMS using only the second commercially available interface; the Liquiface. The system was modified from installation specification to improve peak resolution in the interface and maintain peak separation from the column to the mass spectrometer. The system performance was assessed by the determination of sensitivity, accuracy and precision attained from carbohydrate separations. The system performed satisfactorily after modifications, resulting in maintenance of peak resolution from column to mass spectrometer. The sensitivity achieved suggested that ～150 ng carbon could be analysed with acceptable precision (<0.3‰). Accuracy was maintained in the interface as determined by correlation with offline techniques, resulting in regression coefficient of r² = 0.98 and a slope of 0.99. The average precision achieved for the separation of seven monosaccharides was 0.36‰. The integration of a carbonate removal device limited the effect of background carbon perturbations in the mass spectrometer associated with eluent gradients, and the coupling of strong anion‐exchange chromatography with IRMS was successfully achieved using the Liquiface. Copyright © 2010 John Wiley & Sons, Ltd.     

Time-resolved laser-induced plasma spectrometry for determination of minor elements in steelmaking process samples

A pulsed Nd:YAG laser operating on the fourth (266 nm) and second (532 nm) harmonics has been used to generate plasmas on the target surface in air at atmospheric pressure. The influence of wavelength on quantitative analysis of 4 minor elements in stainless steel samples (Si, Ti, Nb and Mo) was investigated. Stainless steel samples with different elemental concentrations were prepared and analyzed by laser-induced plasma spectrometry (LIPS). The effect of laser wavelength on analytical figures of merit (calibration curves, correlation coefficients, linear dynamic ranges, analytical precision, and accuracy values) was found to be negligible when internal standardization (an Fe line) and time-resolved laser-induced plasma are employed. For both wavelengths, the calibration curves presented a good linearity and an acceptable linear dynamic range in the concentration interval investigated. For the four elements studied, limits of detection lower than 150 microg g(-1) were achieved. To evaluate the influence of wavelength on precision and accuracy, a set of fifteen high-alloyed steel samples from different stages of steelmaking process have been analyzed. Finally, the long-term stability of the analytical measurements for Mo with 532 nm wavelength has been discussed. RSD values were lower than 5.3% for the elements studied.