The problem with broad peaks can occur due to following reasons:
a) Mobile phase composition changed. Solution: Prepare new mobile phase. b) Mobile phase flow rate too low. Not in the optimum of van Deemter curve. Solution: Adjust flow rate. c) Leak, especially between column and detector. Peaks will be broad with lower peak height! Solution: Check system for loose fittings. Check pump for leaks, salt build-up and unusual noises. Change pump seals if necessary. d) Detector settings incorrect. Solution: Adjust settings. e) Column overloaded. Peaks will be broad with high peak height. Solution: Inject smaller volume or dilutions of sample (e.g. 1:10, 1:100). f) Detector response time or cell volume too large. Solution: Reduce response time or use smaller cell. g) Tubing between column and detector too long or ID too large. Solution: Use as short a piece of 0.007– 0.010’’ ID tubing as practical. h) Buffer concentration too low. Peaks will be broad without tailing etc. Solution: Increase concentration. i) Guard column contaminated. Solution: Replace guard column. j) Column contaminated/worn out. Solution: Replace column with new one of same type. If new column provides symmetrical peaks, flush old column and retest. k) Void at column inlet. Solution: Replace column. l) Peak represents two or more poorly resolved compounds. Solution: Change column type to improve separation. m) Column temperature too low. Solution: Increase temperature. Do not exceed recommended temperature (45 °C for Eurospher and 90 °C for Eurokat).