Common Mistakes and Troubleshooting

A frequently observed standardisation failure is the use of an uncertified or insufficiently pure reference standard for marker compound quantification,...

A frequently observed standardisation failure is the use of an uncertified or insufficiently pure reference standard for marker compound quantification, which introduces a systematic quantification error that may not become apparent until an external audit or regulatory review; reference standards should always be sourced from a certified supplier with a documented certificate of analysis. Where HPLC precision fails to meet the required relative standard deviation threshold, column ageing, mobile phase degradation, or sample instability during the injection sequence are the most common causes, and should be investigated in that order before the method itself is questioned. Heavy metal limit exceedances are most often traced to the collection site rather than to processing, making pre-collection soil and site screening a more effective long-term control measure than attempting to remediate contaminated raw material after the fact.