Spectrometric analytical methods

While the ECNI high resolution mass spectrometric method offers unmatched specificity because of the high degree of sophistication and their high cost, these instmments are not available in most analytical laboratories. In light of this, more recent efforts have gone into improving on the early ECNI low resolution mass spectrometric analytical methods. 

Somewhat later, Travis and Busch reported that extraction of the residue from Eq. (6.8) with hot ethanol afforded the dimer of 10 in 25% yield . The latter, 1,4,8,11, 15,18,22,25-octathiooctacosane, was characterized by mass spectrometric analysis as well as the customary analytical methods. It was found that by dilution of reactants prior to mixing, the yield of [monomer] is greatly increased (50—60%) while the yield of [dimer] is lowered substantially . One might have expected the larger rather than the smaller ring to be more favored at higher dilution, but there is no further comment on this point. 

There are methods available to quantify the total mass of americium in environmental samples. Mass spectrometric methods provide total mass measurements of americium isotopes (Dacheux and Aupiais 1997, 1998 Halverson 1984 Harvey et al. 1993) however, these detection methods have not gained the same popularity as is found for the radiochemical detection methods. This may relate to the higher purchase price of a MS system, the increased knowledge required to operate the equipment, and the selection by EPA of a-spectrometry for use in its standard analytical methods. Fluorimetric methods, which are commonly used to determine the total mass of uranium and curium in environmental samples, have limited utility to quantify americium, due to the low quantum yield of fluorescence for americium (Thouvenout et al. 1993). 

Various analytical methods have made quantum leaps in the last decade, not least on account of superior computing facilities which have revolutionised both data acquisition and data evaluation. Major developments have centred around mass spectrometry (as an ensemble of techniques), which now has become a staple tool in polymer/additive analysis, as illustrated in Chapters 6 and 7 and Section 8.5. The impact of mass spectrometry on polymer/additive analysis in 1990 was quite insignificant [100], but meanwhile this situation has changed completely. Initially, mass spectrometrists have driven the application of MS to polymer/additive analysis. With the recent, user-friendly mass spectrometers, additive specialists may do the job and run LC-PB-MS or LC-API-MS. The constant drive in industry to increase speed will undoubtedly continuously stimulate industrial analytical scientists to improve their mass-spectrometric methods. 

A conventional analytical method, like solvent extraction-graphite furnace atomic absorption spectrometric detection, requires a contamination-free technique. Moreover, it is time-consuming and troublesome, as litres of the sample solution must be treated because the dissolved concentration of iron in oceanic waters is extremely low (lnmol/1 = 56ng/l). Martin et al. [341] recently found that the dissolved concentration of iron was less. 

Analytical methods for detection of nickel in biological materials and water include various spectrometric, photometric, chromatographic, polarographic, and voltametric procedures (Sunder-man et al. 1984 WHO 1991). Detection limits for the most sensitive procedures — depending on sample pretreatment, and extraction and enrichment procedures — were 0.7 to 1.0 ng/L in liquids, 0.01 to 0.2 pg/m3 in air, 1 to 100 ng/kg in most biological materials, and 12 pg/kg in hair (WHO 1991 Chau and Kulikovsky-Cordeiro 1995). 

Analytical methods for determining disulfoton in environmental samples are reported in Table 6-2. The steps included in the methods are solvent extraction, purification and fractionation, and gas chromatographic analysis. Other analytical techniques, including capillary gas chromatography with mass selective detection (Stan 1989), high-performance liquid chromatography with either mass spectrometric (MS) or MS-MS detection (Betowski and Jones 1988), have been used to determine disulfoton in environmental samples. 

Mass Spectrometric Instrumentation Used in Infusion or Direct Analytical Methods for Chemical Identification and Structure Elucidation. 152... 

Antignac, J.-E, Le Bizec, B., Monteau, E, and Andre, F. (2003), Validation of analytical methods based on mass spectrometric detection according to the 2002/657/EC European decision Guideline and application, Anal. Chim. Acta, 483, 325-334. 

Practically concurrent with the growing utilization of automatic computers in industry has been the expanding use of various spectrometric methods for routine laboratory analyses. This coincidence is not entirely due to chance, because it seems doubtful that these analytical methods could have achieved their present wide acceptance had it not been practical for computers to do the calculations associated with them. These calculations are quite similar in the several applications, involving the solution of a system of linear simultaneous equations for each analysis. 

The most frequently applied analytical methods used for characterizing bulk and layered systems (wafers and layers for microelectronics see the example in the schematic on the right-hand side) are summarized in Figure 9.4. Besides mass spectrometric techniques there are a multitude of alternative powerful analytical techniques for characterizing such multi-layered systems. The analytical methods used for determining trace and ultratrace elements in, for example, high purity materials for microelectronic applications include AAS (atomic absorption spectrometry), XRF (X-ray fluorescence analysis), ICP-OES (optical emission spectroscopy with inductively coupled plasma), NAA (neutron activation analysis) and others. For the characterization of layered systems or for the determination of surface contamination, XPS (X-ray photon electron spectroscopy), SEM-EDX (secondary electron microscopy combined with energy disperse X-ray analysis) and... 

The application of SIMS, SNMS, SSMS and GDMS in quantitative trace analysis for conducting bulk material is restricted to matrices where standard reference materials (SRMs) are available. For quantification purposes, the well characterized multi-element SRMs (e.g., from NIST) are useful. In Table 9.5 the results of the analysis by SNMS and the RSCs (relative sensitivity coefficients) for different elements in a low alloy steel standard (NBS 467) are compared with those of SSMS. Both solid-state mass spectrometric techniques with high vacuum ion sources allow the determination of light non-metals such as C, N, and P in steel, and the RSCs for the elements measured vary from 0.5 to 3 (except C). RSCs are applied as a correction factor in the analytical method used to obtain... 

At present, advanced mass spectrometric techniques have been successfully established among a multitude of quite different analytical methods as very powerful tools which are increasingly being employed for high tech research topics and for daily routine analyses in many laboratories worldwide. Numerous different applications in various fields of use, as demonstrated in the several chapters of this book, illustrate the excellent current capability of inorganic mass spectrometry in the multi-element determination of elements in a wide dynamic range (from % range for determination of stoichiometries, e.g., in layered materials, down to the extreme ultratrace level, e.g., in environmental research, speciation analysis and isotope ratio measurements). 

Remane D, Meyer MR, Peters FT et al (2010) Fast and simple procedure for liquid-liquid extraction of 136 analytes from different drug classes for development of a liquid chromato-graphic-tandem mass spectrometric quantification method in human blood plasma. Anal Bioanal Chem 397 2303-2314... 

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