A Validated RP-HPLC Method for Monitoring Pollutants Removal during Microalgae Bioremediation of Polluted Waters

A Reversed-Phase High-Performance Liquid Chromatography (RP-HPLC) method was developed and validated to simultaneously quantify six contaminants of emerging concern (CECs) in the context of microalgae bioremediation. RP-HPLC was chosen for its ability to separate substances of differing polarities, its use of cost-effective and low-toxicity mobile phases, and the capacity to selectively adjust pH for enhanced sample resolution. To validate this method, standard guidelines were followed to evaluate system suitability, linearity, accuracy, precision, recovery, limits of detection and quantification, selectivity and specificity. Limits of detection and limits of quantification were, respectively, 0.017 and 0.051 µg mL^-1 for paracetamol (PAR), 0.024 and 0.072 µg mL^-1 for methylparaben (MP), 0.008 and 0.027 µg mL^-1 for imidacloprid (IMID), 0.014 and 0.041 µg mL^-1 for bisphenol A (BPA), 0.023 and 0.069 µg mL^-1 for triclosan (TCS) and 0.016 and 0.048 µg mL^-1 for ibuprofen (IBU). Precision and accuracy values assessed inter-day and intra-day were all within the acceptance limits of relative standard deviation (%RSD) and %bias of less than 15%. Percentage recovery was determined to be within the acceptable range of 80-120%, except for TCS due to low solubility. Applicability was demonstrated by assessing the effect of contaminant exposure to microalgae cells, and contaminant removal. The developed method is linear, precise and accurate and has been successfully applied to the quantification of the six contaminants during microalgae bioremediation.