Gold Nanoparticles Expiration Dates - Nanopartz

When working with gold nanoparticles, including spheres, rods, micron sized gold and gold nanowires, the Certificate of Analysis and the Storage and Handling instructions are the most important documents you can keep.


Nanopartz only ships using Fedex Overnight Priority Service domestically and Fedex 2 Day International Priority for international orders. They are shipped in thermally insulated sleeves, and if the product requires,cold packs. We use these methods and services not only because our products deserve a shipping method equal to the effort used in manufacturing them, but also because by shipping using these methods, we can minimize the chances of freezing or overheating.   

Important Product Information

Using these methods, we guarantee our products will fulfill the specifications stated in the Certificate of Analysis. These expiration dates can range from 30 days to 1 year depending on the type of product. The specifications shown in the typical Certificate of Analysis detail physical properties as size, charge, absorbance, and more depending on the product. If handled using the procedures stated in the Storage and Handling, we guarantee our products will meet these specifications for the full duration of the shelf life.


I am past the expiration date. Should I replace my product?

If you have handled and stored your product following the guide provided and if you have ensured that you have only used sterile ware to handle your product and stored your product in a refrigerator and not let it froze, your product can last much longer than the expiration date. For some of our bare spheres and rods, we have customers still using Nanopartz products after over seven years of storage.

How do I tell if my product is not storing well?

Nanoparticles are extremely visual in that if they begin to degrade, they will change in color, uniformity, and may sediment or stick to the sides of the storage tube. These are the first signs. The next test is a quick UV VIS absorbance to match the spectrum to the one provided on the Certificate of Analysis. These are the primary ways to evaluate. If you're still not sure, please contact us at and send us a picture of your product. We will be able to tell right away.

What do I do if I'm past my expiration date and need a replacement?

Contact us. We will work with you to provide you a discount on a replacement product.

So what does the Expiration Date mean to me?

It is the date upon which you need to keep an eye on your product and note any visual or performance changes and look to potentially replace.