Spectroscopy ICP emission

It is becoming more and more desirable for the analytical chemist to move away from the laboratory and iato the field via ia-field instmments and remote, poiat of use, measurements. As a result, process analytical chemistry has undergone an offensive thmst ia regard to problem solviag capabihty (77—79). In situ analysis enables the study of key process parameters for the purpose of definition and subsequent optimization. On-line analysis capabihty has already been extended to gc, Ic, ms, and ftir techniques as well as to icp-emission spectroscopy, flow iajection analysis, and near iafrared spectrophotometry (80). 

In addition, a dealumlnated mordenlte was prepared by leaching HM-10 with 0.4 mol dm HCl solution at 323 K for 30 hr. After washing with distilled water, this was treated In a sodium acetate solution at 353 K for 20 hr for the Ion-exchange. The resulting composition of aluminum was measured by Inductively coupled plasma (ICP) emission spectroscopy after digestion In HF. 

Research by Burton and Price (38) demonstrated that Ba/Sr ratios generated by ICP emission spectroscopy (ICP-ES) can be used to infer the diet (marine verses terrestrial) of prehistoric populations. In this experiment we duplicate results obtained by Burton and Price for the Paloma samples. Our results show that the Ba/Sr ratios obtained by LA-ICP-MS are comparable in precision and accuracy to ICP-ES data (Figure 12). Although it is not unexpected that a coastal population would rely heavily upon marine resources, there are applications where this type of research would have value. What we have done here is demonstrate the efficacy of LA-ICP-MS to this line of research by demonstrating that it is possible to generate results similar to those obtained by other analytical techniques. 

Finally, we note that the photocorrosion process is strongly pH-dependent, occurring most readily in strongly acid solutions, and that the presence of a carboxylic acid is required for the occurrence of severe photocorrosion. In Table II we present analytical results, based on inductively coupled argon plasma (ICP) emission spectroscopy, for representative electrolyte solutions after 6-8 hr. of photo-Kolbe electrolysis with n-SrTiC anodes. It can be seen that the formation of soluble strontium and titanium species is... 

Metals can be conveniently determined by emission spectroscopy using inductively coupled plasma (ICP). A great advantage of ICP emission spectroscopy as applied to environmental analysis is that several metals can be determined simultaneously by this method. Thus, multielement analysis of unknown samples can be performed rapidly by this technique. Another advantage is that, unlike atomic absorption spectroscopy, the chemical interference in this method is very low. Chemical interferences are generally attributed to the formation of molecular compounds (from the atoms) as well as to ionization and thermochemical effects. The principle of the ICP method is described below. 

ICP emission spectrometry is renowned for presenting few interferences. Undoubtedly the most serious potential interference in ICP emission spectroscopy is spectral superposition. 

The chromium in a series of steel samples was determined by ICP emission spectroscopy. The spectrometer was calibrated with a series of standards containing 0, 2.0, 4.0, 6.0, and 8.0 p,g K2Cr207 per milliliter. The instrument readings for these solutions were 3.1, 21.5, 40.9, 57.1, and 77.3, respectively, in arbitrary units. 

Human H. G. C., Scott R. H., Oakes A. R. and West C. D. (1976) The use of a spark as a sampling-nebulising device for solid samples in atomic absorption spectrometry, atomic fluorescence and ICP emission spectroscopy, Analyst 101 265-271. 

Meyers S. A. and Tracy D. H. (1983) Improved performance using internal standardisation in ICP emission spectroscopy, Spectrochim Acta, Part B 38 1227-1253. 

Among the various types of atomic spectroscopy, only two, flame emission spectroscopy and atomic absorption spectroscopy, are widely used and accepted for quantitative pharmaceutical analysis. By far the majority of literature regarding pharmaceutical atomic spectroscopy is concerned with these two methods. However, the older method of arc emission spectroscopy is still a valuable tool for the qualitative detection of trace-metal impurities. The two most recently developed methods, furnace atomic absorption spectroscopy and inductively coupled plasma (ICP) emission spectroscopy, promise to become prominent in pharmaceutical analysis. The former is the most sensitive technique available to the analyst, while the latter offers simultaneous, multielemental analysis with the high sensitivity and precision of flame atomic absorption. 

There are some exceptions to the generalizations above. The very refractory metals, e.g., W, Ta, etc., are not reduced to an atomic vapor in the flame and are therefore not accessible to flame AAS. In this case ICP is usually preferable. If the analyte concentration approaches the fig/L level or below, the precision becomes much poorer. In such cases other more sensitive methods are often preferable, for example, furnace AAS. If many metals must be determined in each sample, ICP emission spectroscopy is often more rapid, though it is more expensive and it requires a higher level of operator skill than flame AAS. 

ICP emission spectroscopy is used primarily for the qualitative and quantitative analysis of samples that arc dissolved or suspended in aqueous or organic liquids. I he techniques for preparation of such solutions are similar lo tho.se described in. Section 9D-1 for flame absorption methods. With plasma emission, however, it is possible to analyze solid samples direclly. These procedures include incorporating electrothermal vaporization, la.ser and S[)ark ablation, and glow-discharge vaporization, all of which were described in Section 8C-2. Suspensions of solids in solutions can... 

Figure 11.9. Comparison of results for iron in six samples of orchard leaves. The average value for each sample is the average of the values obtained by a number of independent laboratories using one or more of the techniques given in parentheses. The standard deviation of these values is given for each sample by the error bars, as well as the standard deviation of the results obtained by ICP emission spectroscopy for 7 dissolutions. A recent atomic-absorption value is also given, indicated by . Adapted from R. H. Scott and A. Strasheim, Anal. Chim. Acta, 76, 71 (1975), by permission of the author and publisher.

Standard solutions of inorganic species, both non-metals and metals, are particularly widely used in laboratories. Multielement metal standards, for use in ICP emission spectroscopy and other multielement techniques, must be backed with a guarantee that high-purity components are used in their formulation otherwise, trace impurities in the individual ingredients may contribute significantly toward total quantities of the very elements it is required to measure. Undesirable blanks of this kind are easily overlooked and can seriously degrade analytical performance. 

Laser and inductively coupled plasma (ICP) emission spectroscopy constitute powerful multielement qualitative and quantitative tools for the analysis of metals, paints, and glass. Finally, ICP with mass spectrometry (MS) makes an increasing impact on the analyses of trace evidence from pollution source determination to traditional trace exploitation. 

In prineiple, the extent of sorption of a material can be obtained by subjecting the exposed substrate (e.g., hair) to an extraction procedure involving a highly efficient solvent for the sorbate. In the present eontext, whereas this approach may not be realistic for the usual sorbates (based on C, H, 0, and N) it may be feasible in certain cases. As an example, the work of Yahagi is referred to again. It involved the deposition of silicone on hair (26). In this ease, the exposed hair was extracted with chloroform, the extract dissolved in methylisobutyl ketone, and analyzed by ICP emission spectroscopy. The method could, of course, be extended to aminosilieones. 

All chemicals were reagent grade and were used without further purification. Infrared spectra were recorded on a JASCO FT/IR-350 spectrometer. Mass spectra were measured using a JEOL JMS-TIOOLP. Elemental analyses were performed on a Yanaco CHN corder MT-6. Inductively coupled plasma (ICP) emission spectroscopy was performed on a Shimadzu lCPE-9000. Thermogravimetric analyses were performed on a MAC TG-DTA 2000 in an argon atmosphere at a heating rate of 1 °C min . ... 

Pressouyre, B., Anionic detergents by ICP emission spectroscopy, Analusis, 1989,17,346-354. 

---