1. 'E' means 'times 10 raised to the power'. That is to say; 1.79E+11 means 1.79 x 1011 .

2. From the attachment, the concentration you seek is actually clearly stated. Your order contains 2.98 x 10-10 M of content. This concentration is equal to 2.98 x 10-7 mM = 2.98 x 10-1 nM. The molar concentration was obtained from the wt concentration and molar mass; Molar concentration = wt concentration / Molar mass.

If you want to prepare lesser concentrations by dilution, that is another case but the concentration of the as received order, is clearly stated.

1.79E+11 means 1.79X10^11

To the best of my knowledge, it is impossible to prepare molar (mM, uM, nM ...) solutions of gold nanoparticles. I am not sure, if anyone can definitely state regarding how many Au(0) are associated with each nanoparticles. Is it possible to get nanopartticles of one definite size with definite number of Au(0)?

This is the precise reason, why almost everyone who is working with Au-NPs test their efficacy using ppm solutions. If I am wrong, please correct me.

1. 'E' means 'times 10 raised to the power'. That is to say; 1.79E+11 means 1.79 x 1011 .

2. From the attachment, the concentration you seek is actually clearly stated. Your order contains 2.98 x 10-10 M of content. This concentration is equal to 2.98 x 10-7 mM = 2.98 x 10-1 nM. The molar concentration was obtained from the wt concentration and molar mass; Molar concentration = wt concentration / Molar mass.

If you want to prepare lesser concentrations by dilution, that is another case but the concentration of the as received order, is clearly stated.

Thank you all for your answers.

If I should express the concentration in mol/L, it must be as Mr. Gyan's answer. Problems come up, since the colloidal gold nanoparticles are colloid, not solution, meaning that it does not form homogeneous solution. It could therefore better been express as a number of particles/mL.