Different manufacturers use different naming for their PEG products. When we name our PEG products, we count the number of CH2CH2 units, but we do not include groups at the ends that are bound to carbon. Therefore, in our Biotin-PEG3-azide, there are three CH2CH2 units in the linker. On the contrary, some manufacturers count CH2CH2O units, so the same compound will be called Biotin-PEG2-azide in their terminology.

We do not use counting CH2CH2O units in our naming of PEGs to avoid misleading that arises in this case. For example, alcohols and other derivatives with the same linker will have different PEG names.

Moreover, the number of PEG groups will change after the chemical reaction. For example, if triethyleneglycol is converted to dichloride, it will become PEG2-dichloride.

In summary, to count the number of PEGs for our products, we are guided by the following rules:

- count the number of CH2CH2 units in the PEG linker;

- flanking groups bound to heteroatoms are included in the PEG chain;

- flanking groups bound to carbon are NOT included in the PEG chain.

Find the full list of our PEG products in our catalog.