Question

4. (2pts) Make sure you explain your answers. N = 2 000 plates N=7 500 plates etector response A) Which chromatogram represents a separation that is more efficient? Why? B) How does the particle size of the packing material in the column reflect on the separation? Use an approximate size of the particles to illustrate the difference in chromatogram a) and b). del lagog toy 912 M H E lo missib bold a test2 21GE) Trenden anlato ingilis

HPLC

Answer 1

A) Number of plates is inversely proportional to the square of the peak-width at the half height. Now increasing the plate number decreases the peak width and hence the peak resolution and the inter-peak distance decrease. So, chromatogram b represents more separation efficiency. B) larger the particle size, lesser the separation efficiency. Column length or the plate number is inversely proportional to the size of column packing particle. As small the particles are better will be the separation efficiency. In case b, N is 7500 and case a it is 2000, so the particle size is supposedly bigger in the case of column a leading to limited separation efficiency.