Entwicklung einer Multi-Purpose Ionenquelle für die AP-MS sowie Design und Anwendung von APLI-Ionisationslabeln
Entwicklung einer Multi-Purpose Ionenquelle für die AP-MS sowie Design und Anwendung von APLI-Ionisationslabeln
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AP-MS 的多用途离子发生器设计和 APLI 电离标签的研究
DOI:
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发表时间:
2009
期刊:
影响因子:
--
通讯作者:
Ralf Schiewek
中科院分区:
文献类型:
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作者:
Ralf Schiewek
Atmospheric-Pressure Laser Ionization (APLI) was developed at the University of Wuppertal
as a sensitive atmospheric-pressure ionisation method for the analysis of non-polar aromatic
hydrocarbons. The coupling of liquid chromatography (LC) with APLI was first realised with
a Q-TOF Ultima (Waters) instrument in the form of LC-APLI-(TOF)MS. Because of its great
separating power, gas chromatography presents an interesting alternative to LC. A plan was
therefore drafted for coupling a gas chromatograph with the atmospheric-pressure ion source
of the Q-TOF Ultima for APLI. To this end, an appropriate electrically heated transfer line
was constructed. The front end of this transfer line could be mounted instead of a
volatilisation stage on the otherwise unmodified atmospheric-pressure ion source. The
parameters necessary to operate the source, such as the amounts of gas within the source and
settings on the mass spectrometer, were optimised. The efficiency of this new coupling was
demonstrated by the analysis of a number of standards (PAHs and hetero-PAHs).
On the basis of this successful coupling, APLI was also coupled with another atmosphericpressure
mass spectrometer (micrOTOF, Bruker Daltonics). For this, a new ion source was
developed for the mass spectrometer, to replace the standard one. The central component of
the new source, which can be used for LC as well as for GC versions of APLI-(TOF)MS, is a
cube-shaped source body with several apertures. Various additional components, such as the
volatilisation stage of liquid chromatography or the newly developed transfer line, could be
mounted onto the body. After important parameters had been optimised, a number of
standards as well as real samples were analysed with both the LC-APLI-(TOF)MS and GCAPLI-(
TOF)MS systems, in order to show the potential of this coupling. Thus, in addition to
several aromatic oligomers used in the manufacture of organic light-emitting diodes, which
are difficult to analyse by other methods, transition-metal complexes used as triplet emitters
were successfully analysed by LC-APLI-(TOF)MS. Among examples of the application of
GC-APLI-(TOF)MS, several PAH and hetero-PAH standards were analysed, and the pyrene
metabolite 1-hydroxypyrene was detected in urine. For chrysene, a detection limit of 0.5 ng/L
was achieved with an injection volume of 2 µL.
In order to use the advantages of such a flexible coupling, in which the costly high-resolution
mass spectrometer serves as detector for various chromatographic applications in conjunction
with the three important atmospheric-pressure ionisation methods (ESI, APCI, APPI), these
methods were integrated into the design. In addition, an improved version of the GC-transfer
line was developed. This new design of a Multi-Purpose API-Source (MPIS) has been made
commercially available by the company Bruker Daltonics as a flexible ion source for an
atmospheric-pressure mass spectrometer.
Switching between various ionisation methods is convenient, requiring only that the
alternative components be exchanged at the apertures of the source body. For example, to
switch from GC-APLI-(TOF)MS to GC-APCI-(TOF)MS, only a quartz window is replaced
by the APCI needle assembly. Switching between LC und GC is possible in the same way:
here only the transfer line has to be replaced by a blind flange. In this design, the ionisation
methods can be applied either individually or in combination as true multimode ionisation
(e.g. APLI and APCI simultaneously). The efficiency of the individual modes was
demonstrated with several standards. With this source, ionisation techniques such as ESI,
APCI, APPI and APLI are available for both LC and GC. For LC, the additional multimode
ionisation techniques APLI+ESI and APLI+APCI can be used.
APLI is a selective method for ionising non-polar aromatic compounds. On the one hand, this
represents a limitation to the general applicability of the method, but on the other hand it
makes it possible to ionise this class of compounds selectively in a complex matrix. Therefore
ionisation labels and corresponding strategies for derivatisation were developed for LC-APLI-
(TOF)MS and GC-APLI-(TOF)MS. These ionisation labels are aromatic compounds that can
be detected with high sensitivity. They have an anchor group for covalent coupling with nonaromatic
analytes. The derivative can then be detected sensitively by APLI. A study of
REMPI spectra of several derivatives under atmospheric pressure showed that they do not
differ significantly from those of the labels themselves, which indicates that the electronic
proportion of the aromatic system of the derivative is not significantly influenced by the
analyte. The practical application of the APLI ionisation labels was showen for LC-APLI-
(TOF)MS and GC-APLI-(TOF)MS by study of a number of samples such as Brij® 72 and
PEG 1000 and by the determination of the fatty acid content of vegetable oils and a technical
fatty alcohol mixture.
影响因子:
7.4
作者:
Cech, NB;Enke, CG
通讯作者:
Enke, CG
影响因子:
7.4
作者:
Singh, G;Gutierrez, A;Blair, IA
通讯作者:
Blair, IA
DOI:
10.1002/rcm.1290050604
发表时间:
1991
期刊:
Rapid communications in mass spectrometry : RCM
影响因子:
--
作者:
Voyksner,RD;Pack,T
通讯作者:
Pack,T