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1.
张大成  马新文  朱小龙  李斌  祖凯玲 《物理学报》2008,57(10):6348-6353
激光诱导击穿光谱(LIBS)在植物样品上面的应用是一个较新的课题. 为将LIBS技术能实际应用于与食品安全相关的领域,实验中对三种真空冻干水果样品进行了初步LIBS实验研究,鉴别了其LIBS光谱,并选取典型光谱线,运用统计学方法分析比较了三种水果中Ca,Na,K,Fe,Al,Mg六种元素含量的差别. 实验结果表明,苹果中Na的含量最高,Ca的含量最低,三种水果样品中的K,Fe,Mg等元素含量也都有差异. 实验结果还表明LIBS技术是一种检测、对比植物样品中微量元素含量的有效手段. 关键词: 激光诱导击穿光谱 等离子体 植物样品 微量元素  相似文献   

2.
猪肉内部结构成分复杂,各部位的成分相似,分辨较为困难。结合激光诱导击穿光谱技术,通过光谱分析的方式提高分类精度。以5种不同部位的长白山黑猪肉(里脊肉、梅花肉、后腿肉、前腿肉、五花肉)作为待测样品,通过冷藏、切片等预处理方法,探究激光诱导击穿光谱技术鉴别猪肉脂肪与肌肉及其不同部位的可行性。首先通过采集猪肉脂肪样品与肌肉样品的LIBS谱线信息发现,猪肉中Mg,K,Fe,Cu,Ca和Na等元素较为丰富,并在脂肪样品光谱中发现C-N键,与肌肉样品LIBS谱线信息相比,脂肪样品受其内部水分、有机质成分影响致使其谱线信息背景和噪声信号干扰较大,二者谱线信息存在一定差异,说明LIBS可对脂肪组织与肌肉组织进行鉴别。通过对目标元素Ca,Na,Mg,K和Al其LIBS特征谱线强度进行检测,计算Mg/Ca,Al/Ca,Na/Ca和K/Ca比值,发现与Al/Ca和Mg/Ca相比,Na/Ca和K/Ca各部位元素比值分布差异明显,在此基础上,根据Na/Ca和K/Ca比值,计算猪肉各部位元素分布决策阈值[(1-α)=90%]。发现与Al/Ca和Mg/Ca比值相比,Na/Ca和K/Ca更能明显的反应出各部位元素分布的不同。其比值分布阈值基本可对猪肉各部位进行区分。以前腿肉与后腿肉为例,前腿肉Na/Ca和K/Ca比值分别分布在1.29~1.58和0.31~0.42,后腿肉Na/Ca和K/Ca比值分别分布在0.98~1.18和0.15~0.23。其元素比值分布无明显重叠。最后,为提高LIBS技术对猪肉不同组织分类的可靠性,将光谱元素强度比值数据与主成分分析法相结合,基本可以实现对猪肉各部位的分类,说明元素特征谱线强度比值在对猪肉各部位分类时具有一定的预测精度。该工作证明,使用激光诱导击穿光谱技术对猪肉进行分类识别等定性分析时具有一定可行性,有望适用于其他生物组织检测分析。  相似文献   

3.
王彩红  王芳  阴军英 《光谱实验室》2012,29(5):2885-2888
用硝酸-高氯酸消解样品,采用火焰原子吸收法测定了大豆中Mg、Mn、Zn、Na、Ca、Fe 6种微量元素的含量.结果表明:在选定的实验条件下,测得大豆中6种元素的含量为Mg >Na>Ca>Fe>Zn>Mn.该方法的相对标准偏差RSD为0.632%-1.623%,平均回收率在91.7%-100.5%之间.  相似文献   

4.
利用激光诱导击穿光谱分析土壤成份   总被引:4,自引:2,他引:2       下载免费PDF全文
 搭建了一套激光诱导击穿光谱实验装置,并通过配置特定样品,开展了一系列激光诱导击穿光谱探测实验。根据含有不同质量分数的同种元素样品的激光诱导击穿光谱实验结果,获得元素质量分数与谱线强度的关系曲线(定标曲线)。对中南民族大学附近的土壤进行激光诱导击穿光谱实验,发现土壤中含有Mg,Ca,Na等18种元素,对河南云台山茱萸峰岩石的激光诱导击穿光谱实验结果仅获得Fe,Mg,Ca 3种金属元素。比较这2种实际样品的激光诱导击穿光谱结果表明,检测样品的物理结构影响激光诱导光谱的实验结果。  相似文献   

5.
阿胶真伪品的X射线荧光光谱的鉴别研究   总被引:2,自引:1,他引:2  
建立了快速鉴别阿胶真伪的新方法.收集6个不同产地的阿胶样品,采用X射线荧光光谱法(XRF)测定了各样品元素种类、含量并作出了元素特征谱,与阿胶对照品的元素特征谱作对比分析.结果表明:6个样品中共有的主要元素为Ca,Na,Cl,K,Fe,Zn,Al和Mg等,但其中Cl,Ca,Na和K元素的含量却与对照品有着显著的差异,且部分特有微量元素只存在于个别样品中.依据这些不同点可以准确地对阿胶的真伪及伪劣品中有害元素的引入来源作出识别和判断.基于XRF法所作的元素特征谱可简捷快速、直观有效的鉴别阿胶真伪,有望应用于其他中药的鉴定.  相似文献   

6.
针对激光诱导击穿光谱技术(LIBS)中等离子体的发射光谱增强问题,提出一种磁场增强LIBS与纳米颗粒增强LIBS(NELIBS)相结合的方法。采用热蒸发法在样品表面沉积一层直径20 nm的金纳米颗粒。利用波长为1 064 nm,最大能量为200 mJ的Nd∶YAG脉冲激光器在室温,一个标准大气压下对纯铜和黄铜进行诱导击穿。调整激光能量为30~110 mJ,分别使用传统LIBS、磁场增强LIBS、NELIBS以及两种方法结合对纯铜进行激光诱导击穿,得到特征谱线(Cu Ⅰ 521.8 nm)的强度增强因子和信噪比,并对其增强机理进行分析。在相同环境下使用四种方式对黄铜和纯铜进行诱导击穿以探测样品中的微量元素。当在样品表面沉淀金纳米颗粒或者将沉淀有金纳米颗粒的样品放在磁场中进行诱导击穿时,发现纯铜样品的光谱中存在Mg元素的特征谱线Mg Ⅱ 279.569 nm,黄铜样品的光谱中存在Si元素的特征谱线 Si Ⅰ 251.611 nm。实验结果表明:单独施加磁场约束或增加纳米金颗粒均可以有效增强等离子体光谱强度,但增强效果弱于两种方法结合,磁场约束对光谱的增强效果弱于NELIBS的增强效果。当结合NELIBS与磁场约束LIBS时,谱线增强因子最高可达14.3(Cu Ⅰ 521.8 nm),相比于磁场增强LIBS和NELIBS,最大增强因子分别提高了28%和59%。四种情况中当激光脉冲能量逐渐增大时,等离子体向外膨胀的强度增大,磁场产生的洛伦兹力束缚等离子的能力相对减弱,同时纳米金颗粒对等离子体发射光谱的增强作用被削弱,谱线强度降低,等离子体的增强因子逐渐减小后趋于稳定。通过NELIBS与磁场约束LIBS结合方式,不仅可以有效提高等离子体的发射谱线强度,改善光谱信号信噪比,而且传统LIBS方法中由于谱线强度低、背景噪声大而无法探测的微量元素可以被探测到,LIBS技术对微量元素的探测能力得到显著提高,微量元素的探测下限变得更低。NELIBS与磁场约束LIBS结合的方法具有更高的灵敏度和准确度,为激光诱导击穿光谱技术的谱线增强方法提供了新的思路,在该领域具有广阔的应用前景。  相似文献   

7.
为了验证LIBS测量飞灰中碳含量变化的能力,本文将煤粉与飞灰按照一定比例均匀混合,得到24种含碳量不同的样品.在不同延迟时间下进行激光诱导击穿光谱实验,得到温度指标发射强度比I_(Mg1)/I_(Mg2)随延迟时间的增大而减小,纯飞灰样品的发射强度比I_(Mg1)/I_(Mg2)的数值明显大于其他混入煤粉的样品.样品中发射谱线强度比IAl/ISi1随温度指标I_(Mg1)/I_(Mg2)的增大而减小.飞灰样品加入煤粉后,对等离子体的温度变化有明显影响.同时引入多元分析的方法,将样品中C、Al、Mg、Ca、Fe等元素谱线强度与Si元素谱线强度的比值作为多元回归分析的自变量,碳元素浓度作为因变量,建立不同延迟时间下的回归方程.结果表明,采用多元分析的方法进行定量计算,根据回归模型得到的预测值与参考值之间的误差基本在9%以内.  相似文献   

8.
用火焰原子吸收光谱法对川东獐牙菜中K,Ca,Na,Mg,Fe,Zn,Mn和Cu八种微量元素进行了分析测定.结果显示,用HNO3-HClO4(5∶1)混酸作消化液处理样品,精密度和回收率较好.在选定的实验条件下,川东獐牙菜各元素间相互不干扰,可在一份样品液中进行八种元素的分别测定.川东獐牙菜中含有较丰富的K,Ca和Na,以及Mg和Zn,其含量K>Ca>Mg>Na>Zn>Fe>Cu>Mn.方法的检出限均小于0.097 μg·mL-1,RSD≤2.34%(n=8),加标回收率89.32%~106.65%.  相似文献   

9.
通过单脉冲激光诱导击穿光谱技术(LIBS),测定了Pb(NO_3)_2水溶液中微量重金属元素Pb的LIBS光谱.实验研究溶液中Pb元素的LIBS光谱信号的时间(300 ns-1300 ns)演化特性,得到了本实验的优化实验条件,光谱探测相对激光的延时为800 ns,单脉冲激光能量35 m J.在最佳实验条件下测得Pb微量元素的LIBS定标曲线,计算得到单脉冲LIBS用于Pb(NO_3)_2水溶液中微量金属元素分析的检测限177 ppm.  相似文献   

10.
大百合中微量元素测定的研究   总被引:19,自引:5,他引:19  
研究了火焰原子吸收光谱法同时测定大百合中多种微量元素的条件,测定了在不同生长时期大百合中K,Ca,Na,Mg,Fe,Zn,Mn,Cu和Cr等九种元素的含量,方法的相对标准偏差介于0.2%~2.1%之间,平均回收率在97.8%~104.9%之间,分析结果满意.结果表明,大百合中Zn,K,Ca,Mg和Mn等人体必须的生命元素含量较高,提示了大百合具有较高的营养价值.  相似文献   

11.
Laser-induced breakdown spectroscopy (LIBS) as a powerful analytical technique is applied to analyze trace- elements in fresh plant samples. We investigate the LIBS spectra of fresh holly leaves and observe more than 430 lines emitted from 25 elements and molecules in the region 230-438nm. The influence of laser wavelength on LIBS applied to semi-quantitative analysis of trace-element contents in plant samples is studied. The results show that the UV laser has lower relative standard deviations and better repeatability for semi-quantitative analysis of trace-element contents in plant samples. This work may be helpful for improving the quantitative analysis power of LIBS applied to plant samples.  相似文献   

12.
Commercial low-cost laser induced breakdown spectroscopy (LIBS) has been successfully employed for the quantitative analysis of a Cu-based alloy using a Nd:YAG laser at 1064 nm. The main aim of the present investigation is to explore the benefits of a commercial low-cost LIBS setup. It was recognized that some trace elements such as Al and S could not be detected by LIBS even with a high-resolution spectrometer. The main difficulties in quantifying Cu as a basic component of a brass alloy are related to the self-absorption of Cu spectral lines, with the effect complicated at Cu concentrations higher than 65%. However, few Cu lines such as that at 330.795 nm would be helpful to use due to their lower susceptibility to self-absorption. LIBS, flame atomic absorption spectrometry (FAAS), and wavelength dispersive X-ray fluorescence (WDXRF) were compared for the detection of major and trace metals in the Cu-based alloy. In the case of WDXRF, the brass samples were identified by using a standardless quantitative analysis program depending on a fundamental parameter approach. The quantitative analysis results were acceptable for most of the major and minor elements of the brass sample. Therefore, commercial low cost LIBS would be useful for quantitative analysis of most elements in different types of alloys.  相似文献   

13.
The formation of water trees in high-voltage cables can wreak havoc to power systems. The water tree is produced within the high voltage cable insulator when impurities like sodium and magnesium present in the insulating material react with moist soil to form chlorides. This water tree causes electrical breakdown by short circuiting the metallic conductor and the earth. In this paper we use laser-induced breakdown spectroscopy (LIBS) to detect the potentially dangerous elements that form the water tree in the insulating cable. The LIBS system used for this work consists of the fundamental (1064 nm) of a Nd:YAG laser, four spectrometer modules that cover the visible and near-UV spectral ranges and an ICCD camera with proper delay and gating sequence. With this arrangement we were able to measure the elemental concentrations of trace metals present in the insulating cable. The concentrations measured with our LIBS system were counter checked by a standard technique like inductively coupled plasma (ICP) emission spectrometry. The maximum concentrations for ionic species such as Ba (455.40 nm), Ca (393.36 nm), Cr (267.71 nm), Fe (259.94 nm), Cl (542.3 nm), Mg (516.7 nm), Mn (257.61 nm), Na (589.59 nm) and Ti (334.18 nm) are 20.6, 43.2, 1.6, 148.4, 24.2, 22.1, 4.2, 39.56 and 4.35 ppm, respectively. The relative accuracy of our LIBS system for various elements as compared with the ICP method is in the range of 0.03–0.6 at 2.5% error confidence.  相似文献   

14.
Laser-induced breakdown spectroscopy (LIBS) is a laser-based technique that can provide non-intrusive, qualitative and quantitative measurement of metals in various environments. LIBS uses the plasma generated by a high-energy laser beam to prepare and excite the sample in one step. In the present work, LIBS has been applied to perform elemental analysis of six trace elements simultaneously in aluminum alloy targets. The plasma is generated by focusing a pulsed Nd:YAG laser on the target in air at atmospheric pressure. LIBS limit of detection (LOD) is affected by many experimental parameters such as interferences, self-absorption, spectral overlap and matrix effect. We aimed to improve the LIBS LOD by optimizing these experimental parameters as possible. In doing so, a portable Echelle spectrometer with intensified CCD camera was used to detect the LIBS plasma emission. This advanced Echelle spectrometer provides a constant spectral resolution (CSR) of 7500 corresponding to 4 pixels FWHM over a wavelength range 200–1000 nm displayable in a single spectrum. Then, the calibration curves for iron, beryllium, magnesium, silicon, manganese and copper as minor elements were achieved with linear regression coefficients between 98–99% on average in aluminum standard sample alloys. New LOD values were achieved in the ppm range with high precision (RSD 3–8%). From the application view point, improving LIBS LOD is very important in the on-line industrial process control to follow-up multi-elements for the correct alloying in metals.  相似文献   

15.
我国电站入炉煤种复杂多变,实时快速获取煤质成分对保障锅炉的安全、高效、低污染运行具有重大意义。将激光诱导击穿光谱(LIBS)技术应用于燃煤煤质测量,观测了不同波长激光(355,532和1 064nm)诱导产生的等离子体时间演变特性和不同电离特性元素的谱线时间特性,对比了出现屏蔽效应时的能量阈值随激光波长的变化特征,并研究了激光波长对煤LIBS光谱特性的影响规律。结果发现:使用532nm激光作为激发光源时,煤LIBS光谱具有最强的谱线信号强度,且出现等离子体屏蔽效应的能量阈值也较高,是一种较理想的激发光源,为LIBS技术在煤质测量领域的工业应用提供了实验依据。  相似文献   

16.
激光诱导击穿光谱技术(LIBS)是一种广泛应用于科学和工程方面的元素分析技术。LIBS测量一些微量元素时存在探测极限高的不足,因此增强LIBS信号强度,降低元素探测极限,对扩展其应用范围有着重要的意义。为了实现LIBS光谱信号的增强,提出多次放电增强激光诱导击穿光谱方法,并以固体铝合金材料为例进行了光谱信号强度增强的研究。实验发现,激光作用在铝合金材料上烧蚀样品产生等离子体并溅射到样品上方高压放电电极所在区域,该区域在等离子体产生之后50 μs之内均可以诱导高压电极放电。因此采用高频脉冲电源可以实现一次LIBS产生的等离子体诱导电极多次放电。多次放电会对等离子体进行多次激发,同时多次放电对等离子的加热作用会延缓等离子体冷却速率从而延长等离子体的持续时间,两者共同作用可以增强LIBS光谱信号强度,进而降低LIBS对微量元素的探测极限。使用频率为100 kHz的高频直流脉冲电源,利用数字延迟脉冲发生器同步激光与高压电源,在激光过后3.6 μs触发高压放电,一次LIBS产生的等离子体可以诱导电极5次放电,即对等离子体进行5次激发和加热。利用光谱仪对5次放电等离子体光谱进行积分测量。实验结果表明:使用多次放电增强之后,等离子体持续时间得到大幅延长,光谱信号强度得到大幅增强,其中,Mg Ⅱ (~279 nm)的信号强度可以增强约48倍,Al Ⅱ (~358 nm)的信号强度可以增强约72倍,微量元素Mn Ⅰ (~403 nm)的信号强度增强约6.3倍,微量元素Cu Ⅰ (~403 nm) 的信号强度增强约8.3倍。Mn Ⅰ (~403 nm)和Cu Ⅰ (~403 nm) 的探测极限分别降低为LIBS单次放电的1/6和1/8。多次放电增强激光诱导击穿光谱方法很好地增强了LIBS的光谱信号强度,降低了对微量元素的探测极限,扩展了LIBS技术的应用范围。该方法有潜力应用到贵重物品、稀有材料及文物的鉴定之中。  相似文献   

17.
Laser-induced breakdown spectroscopy (LIBS) was used to analyze the coal samples from the Barapukuria coal mine of Bangladesh and coal from eastern India. Besides the major elements carbon and silicon, a number of minor and trace elements, such as iron, titanium, aluminum, calcium, sodium, copper, zirconium, neodymium, ytterbium, cerium, samarium, dysprosium and gadolinium were identified. In earlier work some researchers identified the lines around 279 and 280 nm as due to Mg II rather than Yb III. The reasons for identifying these two lines as due to ytterbium in the present work are explained. The detection of multiple elements in one experiment in a commonly used fuel demonstrated the versatility and multi-elemental capability of LIBS.  相似文献   

18.
The characterization and accurate determination of the chloride content in cement/concrete is very important for the assessment of the durability and safety of a concrete structure. The available analytical techniques are relatively expensive and time consuming. In this study, a laser-induced breakdown spectroscopy (LIBS) system was used for determination of elemental composition in three different types of cement samples. The plasma was generated by focusing a pulsed Nd: YAG laser at 1064 nm on the cement samples. The concentrations of different elements of significance for structural stability in cement samples were determined. The evaluation of the potential and the capabilities of LIBS as a rapid tool for characterization of cement samples is discussed. The optimum LIBS setup and experimental conditions to detect and measure chloride in building materials are reported. The LIBS results were compared with the results obtained using a standard analytical technique such as inductively coupled plasma emission spectroscopy (ICP–ES). The limits of detection were determined, and calibration curves were measured. The results of this investigation indicate the reliability of LIBS to characterize different cement samples and to assess the chloride content in these cements.  相似文献   

19.
激光诱导击穿光谱技术(LIBS)具有无需样品制备,原位快速分析,可进行实时控制的特点使其在钢铁冶炼控制中具有巨大的实际应用价值。本文以波长为1 064 nm的Nd∶YAG调Q固体激光器为激发光源,CCD为探测器,高合金钢GBW01605—01609系列为样品,在建立的LIBS实验装置上研究激光与合金钢之间的相互作用。系统地研究了观测距离、激光能量对高合金钢样品中激光诱导击穿谱特性的影响,并分析了LIBS信号的时间分辨特性,确定了将LIBS用于合金钢微量元素定量分析时的最佳实验条件。  相似文献   

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