title: Disposable screen printed sensor for the electrochemical detection of methamphetamine in undiluted saliva.
abstract: BACKGROUND
  Methamphetamine has an adverse effect on the ability to drive safely. Police need to quickly screen potentially impaired drivers therefore a rapid disposable test for methamphetamine is highly desirable. This is the first proof-of-concept report of a disposable electrochemical test for methamphetamine in undiluted saliva.
  
  
  RESULTS
  A screen printed carbon electrode is used for the N,N'-(1,4-phenylene)-dibenzenesulfonamide mediated detection of methamphetamine in saliva buffer and saliva. The oxidized mediator reacts with methamphetamine to give an electrochemically active adduct which can undergo electrochemical reduction. Galvanostatic oxidation in combination with a double square wave reduction technique resulted in detection of methamphetamine in undiluted saliva with a response time of 55 s and lower detection limit of 400 ng/mL.
  
  
  CONCLUSIONS
  Using a double square wave voltammetry technique, rapid detection of methamphetamine in undiluted saliva can be achieved, however there is significant donor variation in response and the detection limit is significantly higher than desired. Further optimization of the assay and sensor format is required to improve the detection limit and reduce donor effects.
authors.affiliation: Oxtox Limited, Warren House, 5 Mowbray Street, Stockport, SK1 3EJ UK.
authors.forename: Carrie-Ann
authors.initials: CA
authors.lastname: Bartlett
authors.affiliation: Oxtox Limited, Warren House, 5 Mowbray Street, Stockport, SK1 3EJ UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Taylor
authors.affiliation: Oxtox Limited, Warren House, 5 Mowbray Street, Stockport, SK1 3EJ UK.
authors.forename: Carlos
authors.initials: C
authors.lastname: Fernandez
authors.affiliation: Oxtox Limited, Warren House, 5 Mowbray Street, Stockport, SK1 3EJ UK.
authors.forename: Ceri
authors.initials: C
authors.lastname: Wanklyn
authors.affiliation: Oxtox Limited, Warren House, 5 Mowbray Street, Stockport, SK1 3EJ UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Burton
authors.affiliation: Oxtox Limited, Warren House, 5 Mowbray Street, Stockport, SK1 3EJ UK.
authors.forename: Emma
authors.initials: E
authors.lastname: Enston
authors.affiliation: Oxtox Limited, Warren House, 5 Mowbray Street, Stockport, SK1 3EJ UK.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Raniczkowska
authors.affiliation: Oxtox Limited, Warren House, 5 Mowbray Street, Stockport, SK1 3EJ UK.
authors.forename: Murdo
authors.initials: M
authors.lastname: Black
authors.affiliation: Oxtox Limited, Warren House, 5 Mowbray Street, Stockport, SK1 3EJ UK.
authors.forename: Lindy
authors.initials: L
authors.lastname: Murphy
keywords: Detection; Galvanostatic oxidation; Mediator; Methamphetamine; SWV; Saliva; Screen printed electrode; Square wave voltammetry
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