Quantitative analysis of seized or surrendered drug samples provides valuable insight for health-related services (e.g. treatment, harm reduction) and judicial services (e.g. intelligence gathering). Cocaine is frequently encountered in these samples. This study utilises low- (60 MHz) and high- (500 MHz) field 1 H NMR spectroscopy to quantify cocaine hydrochloride or freebase present within a sample. Method validations were performed on cocaine hydrochloride (in D 2 O) and cocaine freebase (in CDCl 3 ) showing good linearity (R 2 = 0.9967–0.9995), precision (1.53–3.54% RSD) and accuracy (98.4–99.5%). LoD (0.289–0.724 mg/mL) and LoQ (0.875–2.193 mg/mL) were obtained with sample recoveries within acceptable ranges (87.3–111.0%). Quantification was performed using an internal standard (TMS or TSP, median values = 89.39% w /w ( n = 93) and 90.10% w/w ( n = 96) for low- and high-field NMR respectively) or against an externally collected reference standard (median values = 89.90% w /w (n = 93) and 88.43% w/w (n = 96) for low- and high-field NMR respectively). Sample quantification was similar to GC–MS (median value = 84.80% w/w ( n = 92)). Comparable data showcases that acquisition of low-field NMR data can provide relevant and timely (~6 min) quantification of samples containing cocaine. • Cocaine hydrochloride ( n = 87) or freebase samples ( n = 10) were quantified by low- (60 MHz) and high- (500 MHz) field NMR, and GC–MS. • NMR quantification at high- and low-field using an internal standard (TMS or TSP) or an externally collected reference standard produced median values of cocaine content of 89.39–90.10% w /w and 89.90–88.43% w/w respectively. • The median value for cocaine content determined by GC–MS was 84.80% w/w.
Dixon et al. (Sun,) studied this question.