title: Chemometric approach to open validation protocols: Prediction of validation parameters in multi-residue ultra-high performance liquid chromatography-tandem mass spectrometry methods.
abstract: The recent technological advancements of liquid chromatography-tandem mass spectrometry allow the simultaneous determination of tens, or even hundreds, of target analytes. In such cases, the traditional approach to quantitative method validation presents three major drawbacks: (i) it is extremely laborious, repetitive and rigid; (ii) it does not allow to introduce new target analytes without starting the validation from its very beginning and (iii) it is performed on spiked blank matrices, whose very nature is significantly modified by the addition of a large number of spiking substances, especially at high concentration. In the present study, several predictive chemometric models were developed from closed sets of analytes in order to estimate validation parameters on molecules of the same class, but not included in the original training set. Retention time, matrix effect, recovery, detection and quantification limits were predicted with partial least squares regression method. In particular, iterative stepwise elimination, iterative predictors weighting and genetic algorithms approaches were utilized and compared to achieve effective variables selection. These procedures were applied to data reported in our previously validated ultra-high performance liquid chromatography-tandem mass spectrometry multi-residue method for the determination of pharmaceutical and illicit drugs in oral fluid samples in accordance with national and international guidelines. Then, the partial least squares model was successfully tested on naloxone and lormetazepam, in order to introduce these new compounds in the oral fluid validated method, which adopts reverse-phase chromatography. Retention time, matrix effect, recovery, limit of detection and limit of quantification parameters for naloxone and lormetazepam were predicted by the model and then positively compared with their corresponding experimental values. The whole study represents a proof-of-concept of chemometrics potential to reduce the routine workload during multi-residue methods validation and suggests a rational alternative to ever-expanding procedures progressively drifting apart from real sample analysis.
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Torino, Via Pietro Giuria 7, 10125 Torino, Italy; Centro Regionale Antidoping "A. Bertinaria", Regione Gonzole 10/1, 10043 Orbassano, Torino, Italy. Electronic address: ealladio@unito.it.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Alladio
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Torino, Via Pietro Giuria 7, 10125 Torino, Italy; Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, 47907 IN, USA. Electronic address: vpirro@purdue.edu.
authors.forename: Valentina
authors.initials: V
authors.lastname: Pirro
authors.affiliation: Centro Regionale Antidoping "A. Bertinaria", Regione Gonzole 10/1, 10043 Orbassano, Torino, Italy. Electronic address: alberto.salomone@antidoping.piemonte.it.
authors.forename: Alberto
authors.initials: A
authors.lastname: Salomone
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Torino, Via Pietro Giuria 7, 10125 Torino, Italy; Centro Regionale Antidoping "A. Bertinaria", Regione Gonzole 10/1, 10043 Orbassano, Torino, Italy. Electronic address: marco.vincenti@unito.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Vincenti
authors.affiliation: Dipartimento di Farmacia, Università degli Studi di Genova, Via Brigata Salerno 13, 16147 Genova, Italy. Electronic address: riclea@difar.unige.it.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Leardi
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D006993:Hypnotics and Sedatives / Q000032:analysis; D013287:Illicit Drugs / Q000032:analysis*; D016018:Least-Squares Analysis; D057230:Limit of Detection; D008140:Lorazepam / Q000031:analogs & derivatives / Q000032:analysis; D009270:Naloxone / Q000032:analysis; D009292:Narcotic Antagonists / Q000032:analysis; D053719:Tandem Mass Spectrometry / Q000379:methods*; D054928:Validation Studies as Topic
chemical_list: D006993:Hypnotics and Sedatives; D013287:Illicit Drugs; D009292:Narcotic Antagonists; D009270:Naloxone; C023842:lormetazepam; D008140:Lorazepam
keywords: Chemometrics; Multi-residue analysis; Open validation; Partial least squares regression; Prediction of parameters; Ultra-high performance liquid chromatography–tandem mass spectrometry