• 9-chloromethyl anthracene
• determination
• lactate
• saliva
• urine

The present study, reports the application of a method for the determination of lactate in biological matrices (urine and saliva) using a pre-column derivatization procedure with 9-chloromethyl anthracene (9-CMA) and liquid chromatography (RP-HPLC) with fluorescence detection at 410 nm (λex = 365 nm).
The calibration curve was linear in the investigated range 0.05-5.5 mM and the limit of detection was 0.04 mM (slope = 5.19±0.08•105, R2 = 1.000). Intra-day and inter-day repeatability were less than 4 and 3 %, respectively. The calibration curves in urine samples and saliva samples were linear in the same range 0.05-5.5 mM (slope = 3.30±0.17•105, R2 = 0.994 for urine; slope = 5.29±0.26•105, R2 = 0.998 for saliva). Intra-day repeatability was less than 5% (urine) and 3% (saliva). Intra-day recoveries were found to be between 82 and 100 % (urine) and 89 and 102 % (saliva).
The optimized method for the lactate determination was successfully applied to urine of patients from an intensive care unit of Cisanello Hospital (Pisa), in order to determine the correlation between the concentration of lactate in the blood and in urine, and to saliva sampled in several athletes during intensive training.