I do not know what the manufacturer/supplier identifies as the shelf-life of the developer for MLF Chromatography but I have used mine over the course of 2 or 3 years and not noticed any degradation of the solvent or unsatisfactory results. Just be sure to minimize the amount of air contact to assure it is the best quality possible.

I think that it should be good for 12 to 18 months. I usually us it up in less than a year though.

Good idea to replace it each year but this year I used last year’s solvent and it worked fine. You can try yours anyway. if it works it works nothing to loose. I wouldn’t press my luck and go for a third year.

I store the solvent tightly capped in a cool dark place. The intensity of the blue color does fade a bit over time but the solvent is still functional. You may just have to wait a bit longer for the paper to dry and develop to see the results.

My understanding is that it doesn't go bad. Mine lasts me several years.

I have tested for MLF using this solvent for about 5 years and I have yet to throw out a drop. I simply continue to add additional solvent as needed.

I have used the solvent over multiple years. In fact I have used the same solvent for tests in different years. There is nothing on the label or in the Chromatograph Kit instructions that speaks to a shelf life only to store away from heat.

Not an expert....my experience is it lasts longer than one year

I am not a chemist and so I can't answer your question from a chemical breakdown standpoint. But my experience as a user has been that I have not had to replace every year. The solution seems to hold pretty well and perform consistently over time. I store it in a dry and dark environment when not in use.

I have kept a bottle of solvent for several years. I keep it screwed tight and the solvent works fine.