Chromatography Forum

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

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.

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

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.