Plasma emission spectroscopy instrumentation

P. W. J. M. Boumans, ed.. Inductively Coupled Plasma Emission Spectroscopy, 2 Vols. ( Methodology, Instrumentation, and Peformance Applications and Eundamentals),]oVn. Wiley Sons, Inc., New York, 1987. 

Secondary Ion Mass Spectrometry Basic Concepts, Instrumental Aspects, Applications and Trends. By A. Benninghoven, F. G. Ruenauer, and H.W.Werner Analytical Applications of Lasers. Edited by Edward H. Piepmeier Applied Geochemical Analysis. By C. O. Ingamells and F. F. Pitard Detectors for Liquid Chromatography. Edited by Edward S.Yeung Inductively Coupled Plasma Emission Spectroscopy Part 1 Methodology, Instrumentation, and Performance Part II Applications and Fundamentals. Edited by J. M. Boumans... 

An introductory manual that explains the basic concepts of chemistry behind scientific analytical techniques and that reviews their application to archaeology. It explains key terminology, outlines the procedures to be followed in order to produce good data, and describes the function of the basic instrumentation required to carry out those procedures. The manual contains chapters on the basic chemistry and physics necessary to understand the techniques used in analytical chemistry, with more detailed chapters on atomic absorption, inductively coupled plasma emission spectroscopy, neutron activation analysis, X-ray fluorescence, electron microscopy, infrared and Raman spectroscopy, and mass spectrometry. Each chapter describes the operation of the instruments, some hints on the practicalities, and a review of the application of the technique to archaeology, including some case studies. With guides to further reading on the topic, it is an essential tool for practitioners, researchers, and advanced students alike. 

An alternative approach is to analyze the samples using procedures or instrumentation that will give the maximum amount of data for each sample. For example, recent advances in atomic spectroscopy, i.e., inductively coupled argon plasma emission spectroscopy (ICP-AES), allow 20 to 30 elements to be detected simultaneously. 

The increased reproducibility of spark emission is more conducive to quantitative analysis than is arc emission. Spark emission spectrometers often employ a more sophisticated detection system. Rather than impinging on a photographic plate, the dispersed radiation passes onto an array of photomultiplier tubes positioned at preset wavelengths. The photomultiplier is more accurate and faster to use in quantitative measurements than film (12). Such an instrument is called a direct reader and will be discussed further in relation to inductively coupled plasma emission spectroscopy. 

The sodium hydroxide is titrated with HC1. In a thermometric titration (92), the sflicate solutionis treated first with hydrochloric acid to measure Na20 and then with hydrofluoric acid to determine precipitated SiCC. Lower sihca concentrations are measured with the silicomolybdate colorimetric method or instrumental techniques. X-ray fluorescence, atomic absorption and plasma emission spectroscopies, ion-selective electrodes, and ion chromatography are utilized to detect principal components as well as trace cationic and anionic impurities. Fourier transform infrared, ft-nmr, laser Raman, and x-ray... 

Boumans PWJM (1987b) Basic concepts and characteristics of ICP-AES. In Boumans PWJM, ed. Inductively coupled plasma emission spectroscopy part 1, Methodology instrumentation and performance (Vol 90 of Chemical Analysis), pp. 100-257. John Wiley Sons, New York. 

Table 10-1 lists Ihe most iniporlani properties of Ihe ideal instrument for plasma emission spectroscopy. The ideal spectrometer is not available today, partly because some of these properties are mutually exclu sive. Tor example, high resolution requires Ihe use of... 

A number of very useful and practical element selective detectors are covered, as these have already been interfaced with both HPLC and/or FIA for trace metal analysis and spe-ciation. Some approaches to metal speciation discussed here include HPLC-inductively coupled plasma emission, HPLC-direct current plasma emission, and HPLC-microwave induced plasma emission spectroscopy. Most of the remaining detection devices and approaches covered utilize light as part of the overall detection process. Usually, a distinct derivative of the starting analyte is generated, and that new derivative is then detected in a variety of ways. These include HPLC-photoionization detection, HPLC-photoelectro-chemical detection, HPLC-photoconductivity detection, and HPLC-photolysis-electrochemical detection. Mechanisms, instrumentation, details of interfacing with HPLC, detector operations, as well as specific applications for each HPLC-detector case are presented and discussed. Finally, some suggestions are provided for possible future developments and advances in detection methods and instrumentation for both HPLC and FIA. 

Several different methods have been utilized for measuring iron in these biological samples. However, spectrophotometry is the most widely used because it does not require unusual equipment and is readily amenable to automation. Atomic absorption spectrometry is effectively used for tissue and urine analyses [33-35], but unreliable results are obtained with serum due to sensitivity limitations as well as matrix and hemoglobin interferences [35]. Other methods utilizing inductively coupled plasma emission spectroscopy [36], coulometry [37], proton induced X-ray emission [38], neutron activation analysis [39], radiative energy attenuation [40], and radiometry with Fe [41] have been described but, with the exception of coulometry, have not become standard procedures in the clinical chemistry laboratory, inasmuch as sophisticated and expensive instrumentation is required in some instances. However, some of them, e.g., neutron activation, may be the method of choice for definitive accurate analysis. 

A competing method for elemental analysis is inductively coupled plasma emission spectroscopy (ICP-ES). The ICP is capable of much higher temperatures, roughly 10,000 K versus less than 3000 K in the flame, and this allows it to atomize a greater range of elements effectively. The ICP is also less susceptible than the AAS furnace to chemical reaction. However, the plasma generates its own spectra, which limits its sensitivity. Furnace AAS instruments are generally able to detect smaller concentrations of analytes than ICP. 

The analyses for metals in the leachate are undertaken primarily by Atomic Absorption Spectroscopy (AAS) or by Inductively Coupled Plasma Emission Spectroscopy (ICP). These methods make use of the unique absorption or emission spectra that all metal elements possess to quantify their presence in the leachate. The analytical instrument is standardized using multiple concentration levels of the metal elements being tested in the leachate. The absorption or emission is proportional to the concentration of the metal in solution. After standardization, the leachates are aspirated into the analytical instrument, where the metal concentrations are determined by the correlation with the absorption or emission spectra. 

Because light emitted from inductively coupled plasma torches is characteristic of the elements present, the torches were originally introduced for instruments that optically measured the frequencies and intensities of the emitted light and used them, rather than ions, to estimate the amounts and types of elements present (inductively coupled plasma atomic emission spectroscopy. 

Instrumental Quantitative Analysis. Methods such as x-ray spectroscopy, oaes, and naa do not necessarily require pretreatment of samples to soluble forms. Only reUable and verified standards are needed. Other instmmental methods that can be used to determine a wide range of chromium concentrations are atomic absorption spectroscopy (aas), flame photometry, icap-aes, and direct current plasma—atomic emission spectroscopy (dcp-aes). These methods caimot distinguish the oxidation states of chromium, and speciation at trace levels usually requires a previous wet-chemical separation. However, the instmmental methods are preferred over (3)-diphenylcarbazide for trace chromium concentrations, because of the difficulty of oxidizing very small quantities of Cr(III). 

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