Height measurements are the most precise ways to calculate diameter. Lateral dimensions are strongly distorted by tip convolution effects. See: dx.doi.org/10.1016/S0008-6223(98)00046-3

Height measurements can also have distortions. See:

dx.doi.org/10.1016/j.carbon.2008.06.022

dx.doi.org/10.1103/PhysRevB.72.125407

In the software itself there should have an option to measure length/diameter. To know the thickness/height you can draw a line through the particle to get a height profile graph. You can use 3D image mode too for the same. You can contact service engineer of respective AFM company for more details.

Height measurements are the most precise ways to calculate diameter. Lateral dimensions are strongly distorted by tip convolution effects. See: dx.doi.org/10.1016/S0008-6223(98)00046-3

Height measurements can also have distortions. See:

dx.doi.org/10.1016/j.carbon.2008.06.022

dx.doi.org/10.1103/PhysRevB.72.125407

which one...??

u can use SPIP (imagemet.com) or matlab module to calculate the area of highest contrast dots (with a threshold)

I recomend gwyddion as SPM analysis software.

you can also see http://zeus.plmsc.psu.edu/~manias/MatSc597/docs/koutsos3.pdf

for simple geometric consideration

There are calculation methods in the following paper:

Transfusion

Volume 48, Issue 3, pages 451–462, March 2008

You will not get accurate lateral dimension of molecule. Due to tip convolution, sample preparation issue. So better technique is Dynamic Light Scattering. Which will give accurate size of molecule. Using AFM you can get roughly shape of your nanoparticle.

I suggest you check... Http://www.optnano.com/content/1/1/3/abstract

I really very grateful all of you for your valued replies... For your information. I have prepared Cu Nanoparticles by reducing copper chloride with ascorbic acid and PVP. These particles are monodispersed.

You may use the Image J Software for the analysis of its particles sizes n my point of view that is the easiest way of analysis.

You want to measure their size at full width at half maximum of the peak. Measure a statistical number of particles and take the average. If they are fairly uniform, you should a nice low standard deviation. You can see our paper - Ma et al. 2005 Best of luck! Tanya

Thank you

Hi Asim,

How big are your nanoparticles? TEM is a good way to go. That being said, even TEM can give artifacts. For instance, If your nanoparticles are coated, and the coating is a significant contributing factor to their size, you will likely underestimate your nanoparticle size by TEM unless you label your coating with a scatterer.

We have used 5 nm gold spheres to calibrate our AFM for accurate size measurements, and were able to measure them with high accuracy and precision, even using a tip with high radius of curvature. To do so, you need to measure the lateral dimensions using the full width at half maximum to eliminate convolution of the tip shape with the sample feature.

From Ma et al. Microbiology (2005), 151, 3679–3688: "Therefore, to minimize experimental error, we tested all AFM probes (Xu & Arnsdorf, 1994) using colloidal gold particles (0.01% HAuCl4 in 0.02% NaN3) with a radius of 5 nm, showing that our tips were capable of resolving these spheres within the experimental error

[full width at half maximum (FWHM)=5.3 nm±0.4 nm, n=20)."

This was using fairly run of the mill AFM tips: "Si3N4 probe tips (Veeco model #1520-00, k=0.032 nN/nm, nominal resonance n=17 kHz).

I hope this helps!

Best wishes,

Tanya

Thank you Tanya

We use field-flow fractionation (FFF) which is an elution technique, so there is not interference from other particles. As mentioned above, if your sample is mono-dispersed, LS is a great and easy to use technique. If poly-dispersed, then you might have trouble.

I also agree with those who recommend AFM height data to the lateral. Remember that the lateral resolution is limited by the number of pixels.

This paper explains separation of nanoparticles using FFF and imaging the fractions using AFM. To have the best resolution you need a very sharp tip.

http://pubs.acs.org/doi/abs/10.1021/la102942b

Thank you @Shoeleh Assemi

@Shoeleh Assemi........

Please see the attached file and kindly tell me how to calculate Diameter of these particles...

Dear Asim,

I agree with Tamas. Can you put the image? And the section analysis?

If your histogram is obtained from measuring many particles, where the x is the size and the y is the number of particles, then you can use some equations to calculate the number average or weight average size.

Dear Tamas/Shoeleh,

Please see the attached Image.

Dear Tamas/Shoeleh,

Please see the attached Image.

Dear Asim, I cannot open the file. Can you send it to me via e-mail? ([email protected])

Dear Martin, Thank you very much

Dear shoeleh, Plz see your email.

Thank you Tamas... Thats mean we can't measure size using AFM?

Please see the attached pic

I have done some images of my nanoparticles with AFM. I use Gwyddion (qwddion.net) to treat the imagens. I have used various scanning modes and types of tip. My conclusion is that you can measure valuable informations of your "deposited film", but nothing conclusive with respect to particles size, especially if they are very small, as the order of the size of radius of curvatures of the tip. If your last image is the best, I recomend another technique, such as DLS, SAXS, TEM...

Thanks a lot Mr. Janusz Rebis & Mr. V. M. Lenart

AFM is equipped with software which allows you measure dimensions on x, y and z directions.