Ionized atmosphere

Arnold F 1980 The middle atmosphere ionized component Vth ESA-PAG Symposium on European Rocket and Baiioon Programmes and Reiated Research (Bournemouth, UK ESA) pp 479-95... 

The most recent progress in MS analysis of chlorophylls has been obtained with the development of atmospheric ionization methods such as atmospheric pressure chemical ionization (APCl) and electrospray ionization (ESI). These techniques have demonstrated much more sensitivity than thermospray ionization, detecting chloro-... 

In recent decades the hyphenated technique, HPLC-MS, also become the method of preference in HPLC practice. Various techniques have been developed and applied for MS detection such as thermo-spray interface, atmospheric ionization (API), electrospray or ionspray ionization (ESI or ISI), and particle beam ionization. 

The AP-MALDI source is illustrated in Figure 1.17. It works in a similar manner to the conventional MALDI source. The same sample preparation techniques and the same matrices used for conventional vacuum MALDI can be used successfully for AP-MALDI. The main difference is the pressure conditions where ions are produced. Conventional MALDI is a vacuum ionization source where analyte ionization takes place inside the vacuum of the mass spectrometer whereas AP-MALDI is an atmospheric ionization source where ionization occurs under atmospheric pressure conditions outside of the instrument vacuum. 

Spectmm of a Product from the Tryptic Digest of Human Growth Hormone Obtained from a Low Dead Volume Atmospheric Ionization Interface Courtesy of the Perkin Elmer SCIEX Corporation... 

Fig. 1. Schematic representation of atmospheric ionization layers. [After Arnold, Ref. 1].

Arnold F., Middle atmosphere ionized component. Proc. ESA-PAC Symposium on European Rocket Balloon Programmes and Related Research, Bournemouth (UK) 14-18 April 1980 ESA SP-132, 479 (1980). 

Arnold, F., The middle atmosphere ionized component, in Proc of the ESA-Symposium on Rocket- and Balloon-Programmes. Bournemouth, 1980. 

The main criterion for the detector is that it gives a response specifically for tin, rather than the compound. This is because of the detection limits required for environmental analysis, which are not attainable with non-specific detectors. The most popular detection methods for organotin analysis are FPD using a tin selective filter, MS, MIP-AES, and ICP-MS. Recently, HPLC-MS methods based on atmospheric ionization including electrospray, ion spray, or chemical ionization have been used to detect the organotin species. These methods have the advantage that molecular information concerning the analyte is available, rather than just atomic information. 

The QMS with the standard El or chemical ionization (Cl) or atmospheric ionization (API) source is the most... 

An API-Ill triple-quadrupole mass spectrometer (or the single-quadrupole counterpart) with articulated, pneumatically assisted nebulizer atmospheric ionization is available from Perkin-Elmer Sciex Instruments. Any mass spectrometer equipped with an electrospray ionization source capable of LC/MS analysis can be substituted however, some potentials and flows may need to be adjusted for another instrument. A Harvard Apparatus 22 syringe pump is used for sample infusion with 25- 1 Hamilton blunt-tipped (SNR) syringes. 

Measured by using an atmospheric Ionization source. Stated error zEO.8 kj mol"... 

Electrospray is a form of atmospheric ionization, as is atmospheric-pressure chemical ionization (APCl). The latter technique is not quite as relevant for large (polymeric) molecules, because vaporization is required to a larger extent. Because of the greater analyte volatility required, APCl requires higher temperatures than ESI. This can lead to thermal degradation of polymers, but also of low-molecular-weight compounds, such as additives. 

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