动态光散射中的尺寸、分散度和峰值的贴士

Tips about size, PDI, peak value in DLS

Based on Malvern Zetasizer Nano with software V5.10@Win XP

1.      The average size based on intensity weighted average hydrodynamic size,is the only reliable and stable value.

2.      There are three kind of peakvalue, i.e., mode (x axis valuecorresponding to the highest y axis), mean(average) and width (standarddeviation). We can select either one in the reportdesign tool in our software, and the default kind is mean. The number meanappeared in the rightest column of the record table is consistent with the value of peak in number distribution. It’snot as reliable as average size and inconstant even for my highlymono-dispersed NPs for five continuous measurement with 10~20 nm deviation.

3.      Detailed document about “how tocalculate PdI, %Pd, Pd?”, and “How tocalculate average size”

4.      According to Malvern officialterm document, NPs with PDI < 0.04, i.e., %Pd < 20% could be called asmono dispersed system. Also, they mentioned that NPs with such narrow distributionare very rare except of standard NPs samples provided by NIST.

5.      Neither volume distribution nornumber distribution are reliable, compared with intensity distribution, bothsuggested by Malvern and our experience.

DLS document.rar