Development and Validation of a Method Using Dried Oral Fluid Spot to Determine Drugs of Abuse.

A liquid chromatography-mass spectrometry method using dried oral fluid spots was developed and validated for the simultaneous quantification of cocaine, benzoylecgonine, cocaethylene, amphetamine, and 3,4-methylenedioxymethamphetamine. The oral fluid was applied to a Whatman 903 grade paper and submitted to a drying time of 2.5 h. The extraction procedure was optimized by chemometric approach using simplex centroid design. Spots were extracted with a mixture of acetonitrile, buffer, and methanol. Calibration curves covered a linear concentration range of 40-500 ng/mL. Validation parameters of linearity, precision, accuracy, selectivity, carryover, matrix effects, and stability were evaluated and showed satisfactory results. Spot homogeneity was also satisfactory, with less than 15% of deviation from nominal concentration. Spot volume did not influence accuracy when less than 100 µL of the sample was applied to the spot. The validation of the proposed method suggests a potential application in different scenarios in toxicology.

Analysis of cocaine/crack biomarkers in meconium by LC-MS.

Fetal exposure to illicit drugs is a worldwide problem, since many addicted women do not stop using it during pregnancy. Cocaine consumed in powdered (snorted or injected) or smoked (crack cocaine) form are harmful for the baby and its side effects are not completely known. Meconium, the first stool of a newborn, is a precious matrix usually discarded, that may contain amounts of substances consumed in the last two trimesters of pregnancy. Analyzing this biological matrix it is possible to detect the unaltered molecule of cocaine (COC) or its metabolite benzoylecgonine (BZE) and pyrolytic products anhydroecgonine methyl ester (AEME) and anhydroecgonine (AEC). A liquid chromatography mass spectrometry (LC-MS) method was validated for meconium samples after solvent extraction, followed by direct injection of 10µL. Linearity covered a concentration range of 15 to 500ng/mg with a lower limit of quantification (LLOQ) of 15ng/mg for all analytes. Matrix effect was evaluated and showed adequate results. Detection of illicit substances usage can be crucial for the baby, since knowing that can help provide medical care as fast as possible. The method proved to be simple and fast, and was applied to 17 real meconium samples.