The use of a combined portable X ray fluorescence and multivariate statistical methods to assess a validated macroscopic rock samples classification in an ore exploration survey

The combination of “ex situ” portable X ray fluorescence with unsupervised and supervised pattern recognition techniques such as hierarchical cluster analysis, principal components analysis, factor analysis and linear discriminant analysis have been applied to rock samples, in order to validate a “in situ” macroscopic rock samples classification of samples collected in the Boris Angelo mining area (Central Chile), during a drill-hole survey carried out to evaluate the economic potential of this Cu deposit. The analysed elements were Ca, Cu, Fe, K, Mn, Pb, Rb, Sr, Ti and Zn. The statistical treatment of the geological data has been arisen from the application of the Box-Cox transformation used to transform the data set in normal form to minimize the non-normal distribution of the data. From the statistical results obtained it can be concluded that the macroscopic classification applied to the transformed data permits at least, to distinguish quite well in relation to two of the rock classes defined (70.5% correctly classified (p < 0.05)) as well as for four of the five alteration types defined “in situ” (75% of the total samples).     

基于p-FTIR和p-XRF测试组合的大汶口文化蛇纹石质玉器无损检测及产地溯源分析

出土玉器溯源是探索华夏玉器文明起源与演化的关键所在,无损测试技术的进步推动了学术界对出土玉器产地溯源的研究,但至今为止,无损技术仍然是制约出土玉器溯源研究的瓶颈所在。利用便携红外光谱（portable Fourier transform infrared spectroscopy,p-FTIR, 带漫反射附件）+ 便携X射线荧光光谱（portable X-ray flourescence, p-XRF）技术组合对山东省文物与考古研究院发掘的大汶口文化出土蛇纹石质玉器的物相和化学组成进行了无损测试以及出土玉器产地溯源的探索。测试结果显示,大汶口文化的蛇纹石玉存在两种成因类型,其中7件玉器（M1005:3,M1006:4,M1013:12,M20:30,M11,T333:2B①：2,M49:04）属于超基性岩型,Fe,Cr和Ni含量较高,含较多磁铁矿包体,磁性较强,Cr/Ni值小于1且多数小于0.7,与现代泰山玉的产地特征基本一致,最大可能就地取材于附近的泰山山麓,为泰山玉的使用时间提前到5500年前的大汶口文化时期提供了重要的科学依据。另外4件玉器（M2004:1、B型环、M25：26、M26）具有低Fe,Cr和Ni含量,为富镁碳酸盐接触交代变质类型,其来源有待进一步研究确认。上述研究结果确认p-FTIR和p-XRF结合能够实现对考古现场及馆藏多数未知玉器材料的快速鉴定,具有无需制样、矿物类型和元素组成可相互验证、无荧光干扰等优点,对部分特定类型的蛇纹石质出土玉器/材料可进行产地来源分析,是一种有优势的出土玉器无损测试技术组合。     

痕量铬检测传感器的设计与实现

目前药品胶囊中六价铬的检测多通过实验室化学分析方法,精度虽高但难以满足现场检测的需求,针对此问题设计了一种可用于现场检测的痕量六价铬传感器。它包括化学敏感材料、光学激发模块与信号处理模块三部分,化学敏感材料将六价铬浓度转化为光信号,光学激发模块完成激光光源的稳定输出,信号处理模块实现微弱光信号的转换、放大、数据处理与检测结果的显示。实验通过制作的光电转换与信号处理电路完成痕量六价铬的快速检测,实现了检测仪器的小型化与现场检测。结果表明,在六价铬浓度10～500 μg·L-1范围内传感器检测结果呈现良好的线性,拟合后的线性方程为Y=1.542 47*X-2.353 47,线性度为0.998 62,检测下限达到10 μg·L-1,传感器响应时间为90 s,实验中选取5份药用胶囊样品做了对比检测,结果表明该传感器定量检测数据可靠,满足了痕量六价铬低成本、快速、现场检测的需求。     

便携式近红外光谱仪器现状及展望

近红外光谱分析技术具有速度快、操作简单等优点,在农业、制药等行业得到了大量应用,其中一些应用需要将仪器携带到分散的分析现场使用,为满足这一需求,很多体积小、便于移动的便携式近红外光谱仪被研制出来。这些仪器的种类较为繁多,采用了很多不同的基本原理,使用了不同的光路结构。文章综述了国内外便携式近红外光谱仪的技术现状,根据光路结构的不同将仪器分成滤光片型、光栅型、傅里叶变换型、声光可调滤波器型以及使用微机电系统(MEMS)的新型光谱仪等类型,重点介绍各类仪器的原理和主要部分的结构,同时简要介绍不同类型仪器的特点,并列举典型产品。也对测量附件、操作、显示等外围部分的设计作简要介绍,这些附件针对便携应用采取了特殊的设计。通过介绍,为新型便携式近红外光谱仪的研制提供借鉴。最后,对便携式近红外光谱仪器的现状作总结,并对未来国内外技术的发展进行展望。     

微波吸收介质管-微波辅助提取水果中的有机磷农药

使用自行设计的微波吸收介质管辅助加热样品, 建立了一种新的微波加速提取法, 并以正己烷为提取溶剂, 利用改装的便携式微波提取仪提取了水果中的4种有机磷农药. 将微波介质密封于玻璃管内制成微波介质管, 使微波介质可重复使用, 同时加快了提取速度. 提取产物无需纯化, 可直接用于气相色谱-质谱联用(GC-MS)分析. 自行设计改装的交直流两用便携式微波提取仪可用于野外现场的快速样品前处理. 以水果样品为例, 对提取溶剂的种类、 料液比、 提取温度及提取时间等条件进行了优化, 结果表明该方法简便、 快速且高效. 4种有机磷农药的回收率为79.4% ~107.6%, RSD<12.20%, 检出限为0.15 ~0.42 μg/kg.     

On almost-divided domains

Let B be a domain, Q a maximal ideal of B, π: B → B/Q the canonical surjection, D a subring of B/Q, and A:=π ⁻¹(D). If both B and D are almost-divided domains (resp., n-divided domains), then A = B × _B/Q D is an almost-divided domain (resp., an n-divided domain); the converse holds if B is quasilocal. If 2 ≤ d ≤ ∞, an example is given of an almost-divided domain of Krull dimension d which is not a divided domain.      

An X-ray refractive lens comprising two sections cut from a gramophone record for a portable total reflection X-ray fluorescence spectrometer

An X-ray refractive lens is assembled from two sections cut from a gramophone record. The refractive lens is placed in a portable total reflection X-ray fluorescence (TXRF) spectrometer, and it is used for collimation of the incident X-ray beams. A TXRF spectrum measured with the refractive lens is compared with that measured with a waveguide. Compared with the refractive lens, the waveguide enhances the intensities of the X-rays illuminating an analyte. Therefore, fluorescent X-ray intensities increase when using the waveguide. On the other hand, the vertical angular divergence of the incident X-ray beams is smaller when using the refractive lens, and the smaller angular divergence results in a reduction of the scattering of the incident X-rays from a sample holder. Therefore, the spectral background is reduced when using the refractive lens, resulting in an increase of the signal to background ratios of the fluorescent X-rays. Detection limits for 3d transition metals obtained with the refractive lens are sub-nanograms to a few nanograms, and the detection limits are similar to those obtained with the waveguide.     

基于CCD检测器的便携式液体阴极辉光放电光谱仪快速测定卤水中的锂

锂是绿色能源和轻质合金的理想材料,作为一种重要的战略资源而备受各国重视.锂主要来源于盐湖卤水,我国盐湖卤水资源丰富,但主要分布在西部偏远地区,现场勘探和开采急需便携分析仪器的支持,然而目前现有实验分析技术均达不到野外现场分析的目标.近十年来,基于大气压液体阴极辉光放电光谱仪(SCGD-AES)因无需燃气,载气等气流条件及真空环境而受到关注.在前人研究基础上,自行开发了基于CCD光谱仪检测系统的便携式大气压液体阴极辉光放电光谱仪(简称Li-K分析仪),仪器长,宽,高分别为35,19和27 cm,重约为10 kg,十分有利于便携.选择Li的分析谱线波长为67078 nm,以取自西藏两种不同卤水水化学类型样品为研究对象,建立了卤水中Li的快速分析方法.在最佳工作条件下测得Li的检出限为4 ng·mL-1,方法的精密度(RSD)＜2％.研究表明,不同稀释倍数时,Li的分析结果与ICP-MS分析结果相差较大,这可能与溶液的基体效应有关,而采用标准加入法可有效减小基体效应的影响,获得了与ICP-MS较为一致的分析结果,可提高分析结果的准确度.大量实验结果表明,标准加入法只需2个点即可得到Li准确的分析结果,大大减少了实验工作量,为便携式Li-K分析仪在野外现场测定盐湖卤水中的Li奠定了方法学基础.     

Electrochemical Portable Method for on site Screening of Scopolamine in Beverage and Urine Samples

Scopolamine (SCP) is a psychoactive drug often added to beverages for recreational or abuse purposes (loss of memory and non‐consensual practices). In this work, a simple and portable method for fast in field screening of SCP in beverage (beer, coke, energy drink, sugarcane spirit, vodka, and whisky) and urine samples is presented. The proposed method is based on batch injection analysis with square wave voltammetric (BIA‐SWV) detection using boron‐doped diamond (BDD) as the working electrode. A voltammetric profile with accurate information on the presence or absence of SCP is obtained using a small sample volume (～50 μL) and a simple sample pretreatment step (dilution in supporting electrolyte). Around two hundred analyses are possible using the proposed system (injection of single sample plug – 120 μL) without the need of electrodes handling or supporting electrolyte exchange (friendly to point‐of‐care or on site screenings). The quantification of SCP in beverages is also possible using the proposed portable protocol, with a limit of detection of 0.18 μmol L^?1 and recovery values between 87 to 113 %.     

Electronic characterization of lithographically patterned microcoils for high sensitivity NMR detection

Nuclear magnetic resonance (NMR) offers a non-destructive, powerful, structure-specific analytical method for the identification of chemical and biological systems. The use of radio frequency (RF) microcoils has been shown to increase the sensitivity in mass-limited samples. Recent advances in micro-receiver technology have further demonstrated a substantial increase in mass sensitivity [D.L. Olson, T.L. Peck, A.G. Webb, R.L. Magin, J.V. Sweedler, High-resolution microcoil H-1-NMR for mass-limited, nanoliter-volume samples, Science 270 (5244) (1995) 1967–1970]. Lithographic methods for producing solenoid microcoils possess a level of flexibility and reproducibility that exceeds previous production methods, such as hand winding microcoils. This paper presents electrical characterizations of RF microcoils produced by a unique laser lithography system that can pattern three dimensional surfaces and compares calculated and experimental results to those for wire wound RF microcoils. We show that existing optimization conditions for RF coil design still hold true for RF microcoils produced by lithography. Current lithographic microcoils show somewhat inferior performance to wire wound RF microcoils due to limitations in the existing electroplating technique. In principle, however, when the pitch of the RF microcoil is less than 100 μm lithographic coils should show comparable performance to wire wound coils. In the cases of larger pitch, wire cross sections can be significantly larger and resistances lower than microfabricated conductors.