Methodologies mass spectrometry

Figure 2 Rationalization of the detected ions using the Dl model in LMMS by the effects of the (A) energy gradient created along the surface, (B) the pressure gradient in the selvedge, and (C) the time domain of ion formation and mass analysis. (Adapted from Van Vaeck L, Struyf H, Van Roy W, and Adams F (1994) Organic and inorganic analysis with laser microprobe mass spectrometry. Part I instrumentation and methodology. Mass Spectrometry Reviews 13 189-208 Wiley.)...

Van Vaeck L, Struyf H, Van Roy W and Adams F (1994) Organic and inorganic analysis with laser microprobe mass spectrometry. Part 1 Instrumentation and methodology. Mass Spectrometry Reviews 13 189- 209. 

H-I-benzopyrans in, 3, 665 biosynthesis, 3, 877 Mass spectrometry in biosynthesis methodology, 1, 86 heterocyclic compounds reviews, 1, 77... 

The very low Hg concentration levels in ice core of remote glaciers require an ultra-sensitive analytical technique as well as a contamination-free sample preparation methodology. The potential of two analytical techniques for Hg determination - cold vapour inductively coupled plasma mass spectrometry (CV ICP-SFMS) and atomic fluorescence spectrometry (AFS) with gold amalgamation was studied. 

Assuming the sequence of the parent protein is known, it is not necessary to redetermine the whole sequence merely to locate, and sequence, that/those polypeptide(s) that have undergone modification. This can be done by examination of the total-ion-current (TIC) trace before and after protein hydrolysis for the appearance of new polypeptides or to use mass spectrometry methodology to locate those polypeptides that contain certain structural features. Examples are provided here of both methodologies. 

Quantitative methodology employing mass spectrometry usually involves selected-ion monitoring (see Section 3.5.2.1) or selected-decomposition monitoring (see Section 3.4.2.4) in which a small number of ions or decompositions of ions specific to the compound(s) of interest are monitored. It is the role of the analyst to choose these ions/decompositions, in association with chromatographic performance, to provide sensitivity and selectivity such that when incorporated into a method the required analyses may be carried out with adequate precision and accuracy. 

The on-line principle has also been extended into the field of detection (Fig. 8). Thus, it is now possible to record FTIR [27-31] and Raman spectra in situ [32, 33], and there have been considerable advances in the on-line coupling of thin-layer chromatography with mass spectrometry. Here it has been, above all, the research groups of Wilson [34-36] and Busch [37-40] that have made the necessary instrumental and methodological advances, so that TLC must no longer be viewed as merely a clean-up method. Rather it forms the essential central point for all these on-line coupling techniques. 

In line with the policy of Advances to provide periodic coverage of major developments in physical methodology for the study of carbohydrates, A. Dell (London) here surveys the use of fast-atom-bombardment mass spectrometry in application to carbohydrates. This technique has achieved rapid prominence as the soft ionization technique of choice for structural investigation of complex carbohydrate sequences in biological samples. The author s extensive personal involvement in this field makes her chapter a critical, state-of-the-art overview for the specialist, as well as a valuable primer for the reader unfamiliar with this technique. 

The most common final separation techniques used for agrochemicals are GC and LC. A variety of detection methods are used for GC such as electron capture detection (BCD), nitrogen-phosphorus detection (NPD), flame photometric detection (FPD) and mass spectrometry (MS). For LC, typical detection methods are ultraviolet (UV) detection, fluorescence detection or, increasingly, different types of MS. The excellent selectivity and sensitivity of LC/MS/MS instruments results in simplified analytical methodology (e.g., less cleanup, smaller sample weight and smaller aliquots of the extract). As a result, this state-of-the-art technique is becoming the detection method of choice in many residue analytical laboratories. 

HPLC and LC/MS. HPLC methodology coupled with ultraviolet (UV), fluorescence (FL), photodiode-array (PDA) and/or a mass spectrometry (MS) detection has been developed. In general, neonicotinoids can be determined by HPLC/UV. Typical HPLC operating conditions are given in Table 2. 

The use of 2D gel electrophoresis and mass spectrometry to identify proteins was discussed in Chapter 2. Protein expression mapping involves the use of these methodologies to compare expression patterns in different cell types or in the same cell type that has been exposed to different... 

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... 

Von Haller, P.D., Yi, E., Donohoe, S., Vaughn, K., Keller, A., Nesvizhskii, A.I., Eng, J., Li, X.J., Goodlett, D.R., Aebersold, R., Watts, J.D. (2003). The Application of New Software Tools to Quantitative Protein Profiling Via Isotope-coded Affinity Tag (ICAT) and Tandem Mass Spectrometry II. Evaluation of Tandem Mass Spectrometry Methodologies for Large-Scale Protein Analysis, and the Application of Statistical Tools for Data Analysis and Interpretation. Mol. Cell. Proteomics 2, 428 -42. 

The ability to resolve and characterize complicated protein mixtures by the combination of 2DLC and online mass spectrometry permits the combination of sample fractionation/simplification, top-down protein mass information, and bottom-up peptide level studies. In our lab, the simplified fractions generated by 2D(IEX-RP)LC are digested and analyzed using common peptide-level analysis approaches, including peptide mass fingerprinting (Henzel et al., 1993 Mann et al., 1993), matrix-assisted laser desorption/ionization (MALDI) QTOF MS/MS (Millea et al., 2006), and various capillary LC/MS/MS methodologies (e.g., Ducret et al., 1998). 

In this chapter, the main analytical techniques and the methods currently employed in industrial and research laboratories for the analysis of important classes of additives are reviewed. The use of both gas chromatographic and liquid chromatographic methods coupled with mass spectrometry features prominently. Such methodology enables the sensitive and specific detection of many types of organic additives in polymeric materials to parts per billion (jig/kg) levels. Much of the development of these methods has been undertaken as part of research into the migration or extraction of species from food-contact and medical materials [5-7], This chapter also includes some discussion on the analysis of residual monomers and solvents. 

Several methodologies have been published for the determination of selected emerging contaminants in sewage sludge. The most recently reported methods are summarized in Table 1, comprising extraction of the sludge sample, subsequent purification of the extract, and final analysis by either gas or liquid chromatography (GC or LC) coupled to mass spectrometry (MS) or tandem mass spectrometry (MS-MS). 

Regarding the instrumental determination, developed methodologies are based on the use of mass spectrometry (MS), either coupled to gas chromatography (GC) or... 

To obtain reliable information it is necessary to identify and characterize each component in the material. To fulfil this aim, methodologies characterized by high selectivity, specificity and sensitivity are required. Mass spectrometry (MS) is one of the most powerful methodologies for identifying, structurally characterizing, and quantitating wide classes of molecules, ranging from small to very big species. 

Figure 4.1 summarises analytical methodologies in which direct mass spectrometry was used, either in the El mode or by ESI. 

For a proper understanding of the protein binder s function in artworks and historical building materials, it is essential to identify the individual proteinaceous additives and to distinguish them even in materials where they are present in very small amounts, in insoluble forms and often in matrices unsuitable from an analytical point of view. For many materials the appropriate analytical methodology has not been found up to now and, in general, this type of analyses has not become a routine technique. Thanks to the recent development of proteomics (Section 6.2) most of the afore-mentioned problems have been resolved mass spectrometry forms a fundamental platform for this new methodology. 

Traditional methodologies such as 2D-gel electrophoresis and mass spectrometry have been considerably improved to resolve thousands of proteins in a single experiment. However, these approaches are both time consuming and unsuitable for the... 

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