Abstract
A sensitive analytical method has been developed for identification of ubiquinones (UQ- n(H x )) and menaquinones (MK- n(H x )) in activated sludge by liquid chromatography–atmospheric pressure chemical ionization mass spectrometry in negative mode (LC-NI-APCI-MS). Extraction and clean-up of samples were carried out on Sep-Pak Plus Silica solid-phase extraction cartridges. Complete separation of quinones was achieved with an ODS analytical column and using isopropyl ether–methanol (17:83, v/v) as the mobile phase. The compositions of ubiquinones and menaquinones were determined directly using combined information on retention time, the molecular ion mass and fragment ion masses. The lowest instrument quantitative detection limits (LOD inst) for UQ-6, UQ-10, and Vitamin K1 were estimated to be 0.4, 4 and 0.12 ng ( S/ N=10) using LC-NI-APCI-MS in SIM mode, and the lowest method detection limits (LOD meth) achieved by spiking experiment were estimated to be 0.2, 2 and 0.06 μg/g for UQ-6, UQ-10 and Vitamin K1, respectively. On the other hand, the LOD inst for UQ-6, UQ-10, and Vitamin K1 were estimated to be 10, 100 and 2 ng ( S/ N=10) using LC-NI-APCI-MS in full-scan mode, and the LOD meth were estimated to be 7, 60 and 1.2 μg/g for UQ-6, UQ-10, and Vitamin K1, respectively. Both LC-NI-APCI-MS and LC–UV/DAD were applied in the analysis of an activated sludge extract. UQ- n ( n=6–10), MK- n ( n=6–10), MK- n(H 2) ( n=7–10), MK- n(H 4) ( n=8–9) and MK-8(H 6) were detected by LC-NI-APCI-MS, while UQ-6, UQ-7, MK-7(H 2), MK-9 and MK-10(H 2) were not found by LC–UV/DAD. These results suggest that LC-NI-APCI-MS is more sensitive than LC–UV/DAD for the analysis of quinones in environmental samples such as sediment, activated sludge and bio-film in biological processes and other aquatic environments.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.