Forensic and Analytical Toxicology Facility, International Forensic Research Institute (IFRI), Department of Chemistry and Biochemistry, Florida International University, Miami, FL, USA.
Center for Children and Families, Florida International University, Miami, FL, USA.
J Chromatogr B Analyt Technol Biomed Life Sci. 2018 Aug 15;1092:313-319. doi: 10.1016/j.jchromb.2018.06.025. Epub 2018 Jun 20.
Methylphenidate (MPH), which is metabolized into ritalinic acid (RA), is an amphetamine derivative largely used in the treatment of attention-deficit hyperactivity disorder, a neurological condition commonly diagnosed in early childhood. Ensuring that patients comply with clinical treatment is crucial and compliance is generally monitored in blood or urine specimens which, especially in the case of children, can be challenging to obtain on a repetitive basis. Here we report validation of a specific, non-invasive, and rapid dilute-and-shoot analytical method for the detection and quantitation of MPH and RA in oral fluid (OF). The method is based on liquid chromatography coupled to triple quadrupole MS with electrospray ionization utilizing dynamic MRM mode. Subject OF specimens were collected using a Quantisal™ device, processed, and diluted for analysis with seven-point quadratic calibration curves (weighting of 1/x) using MPH-d and (±)-threo-RA-d as internal standards. QC samples and diluted specimens showed intra- and inter-day bias and imprecision values no greater than ±12%. The LOD and LOQ for MPH were 0.1 and 0.5 ng/mL, respectively, and 0.2 ng/mL and 0.5 ng/mL for RA, respectively, indicating the validity of the method for identification and confirmation at low concentrations. Selectivity was specific for the analytes of interest and matrix effects were minimized through the use of internal standard based quantitation.
哌醋甲酯（MPH）代谢为利他林酸（RA），是一种苯丙胺衍生物，主要用于治疗注意力缺陷多动障碍，这是一种常见于儿童早期的神经疾病。确保患者遵守临床治疗至关重要，通常通过血液或尿液样本进行监测，但特别是对于儿童而言，重复获取样本具有挑战性。在这里，我们报告了一种用于检测和定量口腔液（OF）中 MPH 和 RA 的特异性、非侵入性和快速稀释-进样分析方法的验证。该方法基于液相色谱-串联三重四极杆质谱法，采用电喷雾电离，利用动态 MRM 模式。使用 Quantisal™装置收集受试者的 OF 标本，进行处理，并使用 MPH-d 和（±）-threo-RA-d 作为内标，以七点二次曲线（加权 1/x）进行稀释分析。QC 样本和稀释样本的日内和日间偏差和精密度值均不超过±12%。MPH 的检测限和定量限分别为 0.1 和 0.5ng/mL，RA 分别为 0.2 和 0.5ng/mL，表明该方法可用于低浓度的鉴定和确证。选择性针对目标分析物特异性，通过内标定量最小化基质效应。
