LA-FTICR

LA-FTICR Laser ablation Fourier Transform ion cyclotron resonance... 

In physical and theoretical methods there has been a notable increase in the use of recently developed techniques - most of which have trendy acronyms. Thus DRAMA P NMR has been used to determine internuclear P-P distance in a phosphine sulfide 4,8-residue substituted decapeptide, and XANES has been applied to structural studies of phosphine selenides. In the mass spectral field MALDI-TOF has been found to be better than FAB for the determination of the mass spectra of nucleotide triphosphates, LA-FTICR has been used to study tris(cyanoethyl)phosphine and metaphosphates have been detected for the first time by laser photoionisation MS. ERMS was shown to be a powerful technique for the analysis of structurally similar organophosphate insecticides (OPs) and trace quantities of OPs can be determined by Cl using water as the ionising agent. 

Second, in the case of styrene-butadiene copolymers which are used in various applications, the properties are largely dependent on the concentration of each monomer. For this reason, their detailed quantitative characterization is crucial. In this frame, methodology to obtain quantitative information for random styrene-butadiene copolymers has been developed from laser ablation coupled to Fourier transform ion cyclotron resonance mass spectrometry (LA-FTICR-MS) experiments. Contrary to other analytical techniques, the proposed methodology did not require pretreatment. When PS, butadiene rubber (BR), and SBR were laser-ablated... 

According to the high mass resolution and mass accuracy attained by FTMS, ions at miz 69 and 81 amu were specifically detected by LA-FTICR-MS. These ions may be generated differently. On the one hand, it may be assumed that they come from deeper layers of the polymer. Laser ablation involved a greater volume than ion bombardment. By this way, the microvolume involved in the ablation process may lead to the detec-... 

FIGURE 47.2 Positive LA-FTICR-MS spectrum of SBR 1 after 72 h aging treatment at X = 193 nm with a laser power density... 

TABLE 47.2 Measurement and Ion Assignment of the Oxygenated Ions in LA-FTICR-MS Spectrum of SBR 1... 

Quantification and Calibration Ions at m/z 104 and 54 corresponding to styrene and butadiene monomers in the LA-FTICR-MS may be used to perform quantification. Figure 47.5 reports the relative... 

LA-FTICR-MS intensities of ions at m/z 54 and 104 as a function of the bulk styrene molar concentration at the three different used wavelengths. A linear relationship is expected if there are no matrix effects. Thus, IioV I54 should be equal to Ks,yXstj/KbutXbut, where Kj, and Kbut are proportional coefficients for styrene and butadiene and Xsty and Xb t are the intensity of the ion considered for each monomer. 

FIGURE 47.5 Relative I104/I54 LA-FTICR-MS intensity ion, as a function of bulk styrene molar percent at 193 (circle), 266 (square), and 355 nm (triangle). 

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