Elemental analysis mass spectrometry

The pyrolysis products were analyzed by using several techniques. The gas samples collected were analyzed by using gas chromatography and mass spectrometry. Elemental analysis and proton NMR and 13C NMR analysis were performed on the initial reactant and the final distillable liquid products. 

The most frequently used techniques for the structural elucidation of photodegradation products are IR spectroscopy, mass spectrometry, elemental analysis, and nuclear resonance spectroscopy. Degradation products for use with these methods... 

The first synthesis of molecules of this kind was reported independently by Vogtle [52] and Hall [51] and both involved condensation of 34 with a range of diazamacrocycles 37 under high dilution conditions to form the corresponding amide cryptands 38 together with dimeric analogues 39 and some polymers. The compounds were easily separated by column chromatography on alumina and were fully characterised by mass spectrometry, elemental analysis, and multinuclear NMR... 

Reaction of triquinphosphorane (95) with BF3 etherate gave a mixture of two isomeric BF3 adducts (96ab), in which the hydrophosphorane structure was preserved. The products were characterised by mass spectrometry, elemental analysis, IR, multinuclear ( B, F, P) NMR and X-ray... 

P. Dreyfuss In some earlier work with Eckstein, we have done extensive work on the reactions of amines with triethanol silanol and/or fumed silica. Evidence from infrared, nmr, mass spectrometry, elemental analysis and preparation of model compounds all consistently indicate that chemical bonds do form. Amines are known to react in a variety of ways in the course of the synthesis of polyurethanes, as I m sure you know. Thus we have no doubt that chemical bonds can and do form. References to our earlier work can be found both in the preprint and in our paper on the present work. 

Under routine conditions, enrichment and isolation of single anthocyanins followed by classical structural elucidation (mass spectrometry, elemental analysis, UVA IS absorbance evaluation using shift reagents, NMR, thin layer chromatography of sugars and anthocyanidins) is rarely necessary, hence will not be discussed in detail. Routine analysis focuses on the quantification and the distribution of known anthocyanins to confirm the content and source of anthocyanins. 

These salts were characterized by IR, Raman and NMR spectroscopy, mass spectrometry, elemental analysis. X-ray, and initial safety testing (impact and friction sensitivity). Low impact sensitivities were demonstrated. Densities and thermochemical characteristics of substituted amino, amino-methyl, and polymethyl tetrazolium salts are summarized in Table 5. All of these new salts exhibit thermal stabilities > 170°C based on DSC/TGA studies (except the azide). The densities of l-amino-4,5-dimethyl tetrazolium perchlorate (45b) and l-methyl-4,5-diamino tetrazolium dinitramide (50b) are markedly higher than the others. 

Physical determination results are reported elsewhere. Briefly analysis involving pyproprobe-chemical ionization mass spectrometry, elemental analysis, infrared spectroscopy and... 

In contrast to thermal ionization methods, where the tracer added must be of the same element as the analyte, tracers of different elemental composition but similar ionization efficiency can be utilized for inductively coupled plasma mass spectrometry (ICPMS) analysis. Hence, for ICPMS work, uranium can be added to thorium or radium samples as a way of correcting for instrumental mass bias (e g., Luo et al. 1997 Stirling et al. 2001 Pietruszka et al. 2002). The only drawback of this approach is that small inter-element (e g., U vs. Th) biases may be present during ionization or detection that need to be considered and evaluated (e.g., Pietruszka et al. 2002). 

Other modifications to the reaction conditions of the Brust-Schiffrin method, such as a reduction temperature of — 78 °C and the use of a hyperexcess of hexanethiol, results in an Au38(thiolate)24, based on observations, LDI-TOF mass spectrometry, TGA analysis and elemental analysis [69]. The influence of preparation temperature on the size and monodispersity of dodecylthiol monolayer protected gold clusters has also been reported. Both and SAXS measurements show that higher temperatures increase polydispersity. This modification of poly-dispersity may be related to the existence of a dynamic exchange of thiols at the particle surface with thiols in the solvent [70]. 

In addition to characterization of the structure of chromophores and chromo-phore-containing polymer materials by standard techniques [such as FT-NMR, FT-IR, mass spectrometry, UV-Visible spectrometry, elemental analysis, thermal methods (including TGA, DSC, and TMA), and electrochemical (e.g., cyclic voltammetry) methods], characterization of relevant optical and nonlinear optical properties must be carried out for both chromophores and chromophore-containing polymer materials. 

Filter collection, Impactor Chemical analysis of collected sample hr (colorimetric, ion-chromatography, mass spectrometry, element-specihc analysis, etc.) ... 

See also Activation Analysis Neutron Activation. Atomic Absorption Spectrometry Principles and Instrumentation. Atomic Emission Spectrometry Principles and Instrumentation. Chromatography Overview Principles. Gas Chromatography Pyrolysis Mass Spectrometry. Headspace Analysis Static Purge and Trap. Infrared Spectroscopy Near-Infrared Industrial Applications. Liquid Chromatography Normal Phase Reversed Phase Size-Exclusion. Microscopy Techniques Scanning Electron Microscopy. Polymers Natural Rubber Synthetic. Process Analysis Chromatography. Sample Dissolution for Elemental Analysis Dry... 

Trace element glasses (a) 500 ppm (b) 50 ppm (c) Ippm (d) 0.02 ppm Homogeneous batches of doped glass drawn into canes by modified Czochralski technique (a) See Table 3 (b) See Table 4 (c) See Table 5 (d) See Table 6 Isotope dilution mass spectrometry, activation analysis, polarography, spectrophotometry, spark source mass spectrometry, flame emission, atomic absorption... 

Eassett, J. D. Paulsen, P. J. Isotope Dilution Mass Spectrometry for Accurate Elemental Analysis, Anal. Chem. 1989, 61, 643A-649A. 

To examine a sample by inductively coupled plasma mass spectrometry (ICP/MS) or inductively coupled plasma atomic-emission spectroscopy (ICP/AES) the sample must be transported into the flame of a plasma torch. Once in the flame, sample molecules are literally ripped apart to form ions of their constituent elements. These fragmentation and ionization processes are described in Chapters 6 and 14. To introduce samples into the center of the (plasma) flame, they must be transported there as gases, as finely dispersed droplets of a solution, or as fine particulate matter. The various methods of sample introduction are described here in three parts — A, B, and C Chapters 15, 16, and 17 — to cover gases, solutions (liquids), and solids. Some types of sample inlets are multipurpose and can be used with gases and liquids or with liquids and solids, but others have been designed specifically for only one kind of analysis. However, the principles governing the operation of inlet systems fall into a small number of categories. This chapter discusses specifically substances that are normally liquids at ambient temperatures. This sort of inlet is the commonest in analytical work. 

Few of the naturally occurring elements have significant amounts of radioactive isotopes, but there are many artificially produced radioactive species. Mass spectrometry can measure both radioactive and nonradioactive isotope ratios, but there are health and safety issues for the radioactive ones. However, modem isotope instmments are becoming so sensitive that only very small amounts of sample are needed. Where radioactive isotopes are a serious issue, the radioactive hazards can be minimized by using special inlet systems and ion pumps in place of rotary pumps for maintaining a vacuum. For example, mass spectrometry is now used in the analysis of Pu/ Pu ratios. 

Wangzhao, Z., Advanced Inductively Coupled Plasma Mass Spectrometry Analysis of Rare Elements, Balkema Publishers, 1999. 

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