Analysis of the Natural Organic Compound SAAF by Using the TOF-TOF Option
Sperm activating and attracting factor (SAAF) is a naturally occurring substance produced by ascidians (sea squirts) to promote the fertilization process. Previously, the structure of this compound was characterized by high-energy collision induced dissociation (CID) using a traditional four sector tandem double focusing mass spectrometer.1
In this work, we analyzed the SAAF from a ciona intestinalis by using a JMS-S3000 SpiralTOF™ equipped with the optional TOF-TOF analyzer to generate a high energy CID product ion spectrum for this compound.
Results and Discussion
Fig. 1 shows the SAAF mass spectrum acquired using PEG sulfate 600 as an external calibrant. The spectrum shows a peak at m/z 515.301, which is suspected to be the monoisotopic ion [M-2Na-SO3+H]- (calculated value 515.305). In addition, peaks from SAAF are observed at two other masses: [M-2Na+H]- at m/z 595.255 (calculated value 595.261) and [M-Na]- at m/z 617.237 (calculated value 617.242). Among these peaks, the product ion spectrum was acquired for the [M-2Na-SO3+H]- ion, which had been previously analyzed using a traditional four sector tandem double focusing mass spectrometer.1 Fig. 2 shows the high energy CID results generated by the SpiralTOF-TOF. The negative charge was fixed to the sulfate ester end of the molecule, causing charge remote fragmentation (CRF) to occur. As a result, the spectrum showed peaks that systematically reflected the structure of SAAF, as shown in Fig. 3. This data closely resembles the results obtained using a traditional four sector MS/MS system.1