Coordination ion spray

Von Brocke, A., Wistuba, D., Gfrorer, P., Stahl, M., Schurig, V, and Bayer, E. (2002). On-line coupling of packed capillary electrochromatography with coordination ion spray-mass spectrometry for the separation of enantiomers. Electrophoresis 23, 2963 — 2972. 

Continuous-flow FAB was reported earlier but is of no practical importance nowadays. Only few reports have been published dealing with (offline) coupling of CE to MALDI-MS. Recently, a new ionization approach, coordination ion spray (CIS) MS, has been presented (11) in it, charged coordination compounds are formed on-line. 

C Rentel, P Gfrorer, E Bayer. Coupling of capillary electrochromatography to coordination ion spray mass spectrometry, a novel detection method. Electrophoresis 20 2329-2336, 1999. 

More recently, this same group have used a combination of HPLC-NMR and HPLC-MS to identify analogues of vitamin E found in a palm oil extract rich in such tocopherol derivatives [46]. For the MS, a new technique called coordination ion spray was used in which the addition of silver ions to the HPLC eluent caused the enhanced formation of ions of such non-polar compounds. In addition, the HPLC utilised a C30 column in order to gain suitable chromatographic resolution. The compounds in the mixture comprised vitamin E itself, tocopherol, and five related compounds, some of which were isomeric. Tocopherol has the structure shown below ... 

Fig. 8.19. Coordination ion spray mass spectrum of estradiol extracted from the reversed-phase CEC—CIS-MS separation of estrogenic compounds. Column, 250 x 0.1 mm i.d. packed with 3 pm GROM-SIL ODS-O AB eluent, 4 mmol/1 ammonium acetate, pH 9.0, 50% acetonitrile applied pressure, 8 MPa applied voltage, 15 kV detection, ESI-MS, 0.85 s/spectrum sheath liquid, 100 pg/ml aqueous silver nitrate, 3 pl/min mass spectrum extracted from a reconstructed ion chromatogram of the separation of estriol, estradiol, equiline, and estrone. (Reproduced from ref. [104] with permission of Wiley-VCh).

Gaub M, von Brocke A, Ross G, Kovar KA. High-performance liquid chromatography-coordination ion spray mass spectrometry (HPLC-CIS/MS) a new tool for the analysis of non polar compound classes in plant extract using the example of Piper methysticum Forst. Phytochem Anal 2004 15 300-305. 

In coordination ion-spray MS, various ionic reagents induce charges on the solutes eluting from the chromatography column. Ag(I) adducts with olefins or unsaturated triglycerides or fatty acids permit the sensitive detection of (M Ag) species. 

One of the usual requirements for the use of ESI-MS is that the compounds that are transferred to the gas phase are charged. Stable neutral molecules can be detected as well, provided they have a high proton affinity or form stable complexes with ions (the so-called coordination ion-spray MS, CIS-MS). " Formation of cationic adducts with Lewis acids like Na, K, Ag, or protonation at basic sites of the molecule enables the analysis of otherwise undetected neutral species. Also, oxidation of neutral complexes resulting in monocationic species can occur in solution at the capillary tip before droplet formation takes place. 

For these classes of substances, other methods have been developed, such as the coupling of ESI with an electrochemical cell [20-31], the coordination ion-spray [31-46], or the dissociative electron-capture ionization [37-41]. The APPI or the dopant-assisted (DA) APPI presented by Syage et al. [42, 43] and Robb et al. [44,45], respectively, are relatively new methods for photoionization (PI) of nonpolar substances by means of vacuum ultraviolet (VUV) radiation. Both techniques are based on photoionization, which is also used in ion mobility mass spectrometry [46-49] and in the photoionization detector (PID) [50- 52]. 

An unmodified APCI source can be further employed for the ionization technique coordination ion spray (CIS), which... 

Sandra, P. Medvedovici, A. Zhao, Y. David, F. Characterization of triglycerides in vegetable oils by silver-ion packed-column supercritical fluid chromatography coupled to mass spectroscopy with atmospheric pressure chemical ionization and coordination ion spray. J. Chromatogr. 2000, A 974, 231-241. 

Bayer, E, Gfrorer andRentel, C. Coordination-ion spray-MS (CIS-MS) auniversaldetection and characterization method for direct coupling with separation techniques. Angew. Chem. Int. Ed. 38, 992-995 (1999). 

Seal JR, Porter NA. Liquid chromatography coordination ion-spray mass spectrometry (LC-CIS-MS) of docosahexaenoate ester hydroperoxides. Anal Bioanal Chem. 2004 378 1007-13. 

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