Peak purity in HPLC

[shanmukhpatil]

Dear all,

When the hplc peak shows slight split on the apex of the peak and when it is viewed in Peak purity plot(3D) it shows two absorbance . Does it mean that the compound has two absorbance or it is an impurity eluting with the main compound.

Thanks in advance and regards
SKPatil

[DR]

It means that you most likely have 2 peaks in need of better resolution. It is possible for a single peak to have more than one local max is its spectrum. Peak purity analysis will tell you if the spectrum changes throughout what you may think is a single peak. If it does change, you have coelution of more than one component.

[anupama]

peak purity can be evaluated further in terms of ratiograms . It's possible something is coeluting.

[PJ8]

If it's available run the method down and LC-MS. Provided your analyte/s ionise this is a good way of detemining peak purity by cutting your main peak into sections and looking at the mass spec of each section. If the m/s changes significantly you are likely to be seeing co-elution.