Laser microprobe mass spectrometry LMMS

The potential of laser microprobe mass spectrometry (LMMS) has been investigated for structural characterization of nucleosides and nucleotides. This technique is based on the measurement of ions formed promptly by direct desorption and ionization (DI) of solid microscopic samples. The DI process is very fast for nucleosides, which makes it possible to apply a relatively high laser energy to the sample. In the case of nucleosides, LMMS gives... 

Laser microprobe mass spectrometry (LMMS) confirms the existence of true interlayer complexes between cations and macrocyclic ligands (47). This technique, which provides mass spectra of fragmented solids after irradiation with a laser beam, was first used to characterize the intercalation compounds of crown ether- and cryptand-smectite complexes (47,48). One of the most interesting results derived from LMMS of these materials is the ability to corroborate the macrocycle-interlayer cation complexation, such as cryptand C(222)-Na-montmorillonite vs. Cu-montmorillonite. Alkaline-cryptand complexes are clearly assigned since the m/e values correspond to the sum of both the sodium and cryptand atomic mass (i.e., 399 Daltons for Na /C(222)). Transition metal... 

Laser-microprobe mass spectrometry (LMMS) Photons Ions Chemical composition Chemical structure... 

Principles and Characteristics Laser microprobe mass spectrometry (LMMS, LAMMS), sometimes called laser probe microanalysis (LPA or LPMA) and often also referred to as laser microprobe mass analysis (LAMMA , Leybold Heraeus) [317] or laser ionisation mass analysis (LIMA , Cambridge Mass Spectrome-try/Kratos) [318], both being registered trademarks, is part of the wider laser ionisation mass spectrometry (LIMS) family. In the original laser microprobe analyser, emitted light was dispersed in a polychro-mator. Improved sensitivity may be obtained by secondary excitation of ablated species with an electric spark. In the mass spectrometric version of the laser microprobe, ions formed in the microplasma... 

An important difference between SIMS/SNMS and AES/PES is that the analytical information is derived from sputtered particles in the former case and from the surface in the latter case. Both laser microprobe mass spectrometry (LMMS) and static SIMS provide molecular information on local organic and inorganic compounds at variance to AES,... 

The defining attribute of laser microprobe mass spectrometry (LMMS) is the use of a focused laser to irradiate a 5- 10 pm spot of a solid sample at a power density above 10 W cm. The photon solid interaction yields ions which are mass analysed by time of-flight (TOF) or Fourier transform (FT) MS. The technique is sometimes referred to as laser probe microanalysis (LPA or LPMA), laser ionization mass analysis (LIMA) and laser microprobe mass analysis (LAMMA). 

KF Karl Fischer (coulometry) LMMS Laser microprobe mass spectrometry... 

Today the population is becoming increasingly exposed to ultrafine particles (< 20 nm, e.g., Aerosil, 2) in bodycare and household products. Ion microscopy studies revealed that such particles can, for example, penetrate the horny layer of the skin and can result in unexpected interactions. SIMS and Fourier transform laser microprobe mass spectrometry (FT LMMS) have been applied to study 2 stimulated interaction in thin layers of dermatological gels as a result of UV irradiation.175 For future studies of distribution of ultrafine particles LA-ICP-MS will be employed. 

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.)...

Hgure 3 Scheme for molecular speciation of inorganic compounds using FT-LMMS. (Reprinted with permission from Struyf H, Van Vaeck L, Poels K, and Van Grieken R (1998) Fourier transform laser microprobe mass spectrometry for the molecular identification of inorganic compounds. Journal of the American Society for Mass Spectrometry 9 482-497 Elsevier.)... 

Figure 4 Comparison of the positive and negative ion mass spectra recorded using TOF-LMMS from carnidazole (top) and the corresponding N-oxide (bottom). (Reprinted from Van Vaeck L, Van Espen P, Gijbels R, and Lauwers W (1988) Structural characterisation of drugs and oxygenated metabolites by laser microprobe mass spectrometry (LAMMA). Biomedical and Environmental Mass Spectrometry A 6 121-130 Wiley.)...

Figure 9 In situ analysis of the pigment haemoventosin in the apothecia of a microlichen Haematomma ventosum using FT-LMMS. The structural assignment of the anions of major diagnostic interest is based on the high accuracy m/z data in Table 1. (Reprinted from Van Roy W, Mathey A, and Van Vaeck L (1996) In-situ analysis of lichen pigments by Fourier transform laser microprobe mass spectrometry with external ion source. Rapid Communications in Mass Spectrometry 10 562-572 Wiley.)...

Figure 11 Identification of the interaction products between the triethanolamine oleate additive of a lubricating emulsion and rolled aluminum. Top positive ion mass spectrum recorded using FT-LMMS with an external ion source. Bottom structural assignment of the ions of major diagnostic interest. The corresponding high accuracy miz data are listed in Table 2. The framed structures are indicative of the binding of the additive to aluminum. (Reprinted from Poels K, Van Vaeck L, Van Espen P, Terryn H, and Adams F (1996) Feasibility of Fourier transform laser microprobe mass spectrometry for the analysis of lubricating emulsions on rolled aluminum. Rapid Communications in Mass Spectrometry W 1351-1360 Wiley.)...

Figure 6 Positive ion mass spectrum of high-purity GaAs recorded with TOF-LMMS without (A) and with (B) postionization. (Reprinted from Schueler B and Odom R (1987) Nonresonant multiphoton ionisation of the neutrals ablated In laser microprobe mass spectrometry analysis of GaAs and Hgo.78Cdo.22Te. Journal of Applied Physics 61 4652-4661.)...

The main features of LMMS are summarised in Table 3.27. Laser microprobe mass spectrometry is a valuable tool for inorganic and oi anic analysis. Element location and quantification on the )u.m scale can be achieved (spot analysis) and speciation possibilities are available, which are unsurpassed by other... 

Laser microprobe mass spectrometry has been reviewed [47,328,331,334,337-339] Van Vaeck et al. [330] have discussed possibilities and limitations of LMMS. Darke et al. [53a] have reviewed the instrumental features. A monograph is available [130]. 

LMMS has also been used for direct analysis of normal-phase HPTLC plates (cfr. Chp. T.3.5.4 of ref. [13a]) and for identification of cloth samples by means of fingerprints from dyes and fabric softeners for forensic purposes [350], Applications of laser microprobe mass spectrometry were reviewed [53a, 328,334]. 

Figure 7 Schematic diagram of the FT-LMMS with an external ion source developed at the University of Antwerp. (Adapted from Van Vaeck L, Van Roy W, Struyf H, Adams F, and Caravatti P (1993) Development of a laser microprobe Fourier transform mass spectrometer with external ion source. Rapid Communications in Mass Spectrometry 7 323-331 Wiley.)...

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