There are so many different types of seaweeds that it is hard to give recommendations unless one know what specific types of seaweeds are involved in your trials.

Depending on your goals, you may or may not want a fresh water rinse. Be aware that fresh water leaches many compounds in a matter of seconds, again, depending on the specific type of seaweed.

Good luck!

Hi Digvijay Singh Yadav,

In my experience, shade drying is a good alternative when freeze-drying is not available. Worked well for me on Chlorophyta, Rhodophyta and Ochrophyta-Phaeophyceae. I do my best to harvest samples without shredding them so that I avoid losing seaweed content. I try to clean them at the harvest spot with seawater but I know that sometimes, for some species that is not enough and I try to take some seawater with me for a deeper cleaning at the lab if necessary. Fresh water will definitely leach content as David Myslabodski says and the ones I see leach the most are the Chlorophyta and Rhodophyta, especially if they are shredded, so I would avoid that as much as possible.

Also the longer you take to treat the samples before drying, the more content you lose. Seaweed will naturally leach material as reaction to osmotic stress to survive. If the harvested material is well managed since the harvest source to the drying station and if the latter is well put up together, the leaching will only start at the drying station and this leached material will dry on top of the seaweed material so when you later powder it you will get it anyway within your sample.

Hope this helps. Good luck.

Regards

Loїc