I am working with dibenzothiophene and its alkylated derivatives. When I make aqueous solutions of them and analyze them on HPLC-DAD, I have noticed that their concentrations change over time. I exclude direct photolysis, because they are in amber autosampler vials (glass) and there is no oxidant there. My guess is they absorb to the glass wall. There is no reproducibilty for replicates. Can anyone suggest how can I get reproducibility?
I expect to help you giving some ideas to solve the problem.
“The first monomeric structure we study is formed by a polymerizable segment, which contains one hydroxyl and two primary amino groups. We find that the DBT and its alkyl derivates form stable complexes with these monomeric structures. Complexes are formed via hydrogen bonds at several sites in the monomer and organosulfur compounds; in themonomer, the oxygen, some nitrogen and hydrogen atoms are involved in the formation of hydrogen bonds, while in the organosulfur molecules the sulfur and some hydrogen atoms participate in the hydrogen bonds..”
Hindawi Publishing Corporation, International Journal of Polymer Science, Volume 2014, Article ID 103945, 11 pages
http://dx.doi.org/10.1155/2014/103945
http://www.hindawi.com/journals/ijps/2014/103945/ref/
Analysis and Fate of Dibenzothiophene Derivatives in the Marine Environment
International Journal of Environmental Analytical Chemistry - INT J ENVIRON ANAL CHEM 01/1986; 27:81-96. DOI: 10.1080/03067318608078392
“Compounds solubilized in the water column were identified as methyl-substituted dibenzothiophene sulfoxides and sulfones by HPLC with synchrofluorescence and GC-flame photometric detection.”
Total alkylated polycyclic aromatic hydrocarbon characterization and
quantitative comparison of selected ion monitoring versus full scan gas
chromatography/mass spectrometry based on spectral deconvolution
Journal of Chromatography A, 1205 (2008) 109–116
http://ase.tufts.edu/chemistry/robbat/documents/TotalAlkylatedPAH.pdf
Hi,
I think you should conduct a solution stability test first, by preparing bench top (ambient) and in different temperature (e.g. 2-8 oC) conditioned sample as well as, measure their degradation time from the initial. You mentioned that you have prepared solutions in aqueous medium where bio-degradation may be possible. Some microorganisms require sulfur to grow and sustain their biological activity and this process is known as biodesulfurization (although its a slow process). You may try some organic modifier during sample preparation. Good luck!
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