The assay of Melatonin in saliva by high-performance liquid chromatography-tandem mass spectrometry

Khan, S. A., George, R., Taylor, P., Charles, B. G., McGuire, T., Heussler, H., Cooper, D. and Norris, R. L. G. (2011). The assay of Melatonin in saliva by high-performance liquid chromatography-tandem mass spectrometry. In: 12th International Congress of Therapeutic Drug Monitoring and Clinical Toxicology. 12th International Congress of Therapeutic Drug Monitoring and Clinical Toxicology, Stuttgart, Germany, (490-490). 2-6 October 2011. doi:10.1097/01.ftd.0000400651.94145.ba


Author Khan, S. A.
George, R.
Taylor, P.
Charles, B. G.
McGuire, T.
Heussler, H.
Cooper, D.
Norris, R. L. G.
Title of paper The assay of Melatonin in saliva by high-performance liquid chromatography-tandem mass spectrometry
Conference name 12th International Congress of Therapeutic Drug Monitoring and Clinical Toxicology
Conference location Stuttgart, Germany
Conference dates 2-6 October 2011
Proceedings title 12th International Congress of Therapeutic Drug Monitoring and Clinical Toxicology   Check publisher's open access policy
Journal name Therapeutic Drug Monitoring   Check publisher's open access policy
Place of Publication Philadelphia, PA, United States
Publisher Lippincott Williams & Wilkins
Publication Year 2011
Sub-type Published abstract
DOI 10.1097/01.ftd.0000400651.94145.ba
Open Access Status Not Open Access
ISSN 0163-4356
1536-3694
Volume 33
Issue 4
Start page 490
End page 490
Total pages 1
Language eng
Formatted Abstract/Summary
Aims: Melatonin is a naturally occurring neurohormone to help in regulation of circadian rhythm. Melatonin supplementation has been shown to be effective in the management of circadian rhythm sleep disorders in children with intellectual disability. Measurement of melatonin is vital in paediatric circadian rhythm sleep disorders and pharmacokinetic studies and is still in its infancy as a component of
sleep and circadian rhythm testing. A high-performance liquid chromatographytandem mass spectrometry (HPLC-MS/MS) method for measuring melatonin in human saliva has been developed and validated.

Methods: An Applied Biosystems API 3200 tandem mass spectrometer coupled to Shimadzu LC20 prominence HPLC system was utilized. Instrument parameters were optimized for melatonin and internal standard, deuterated melatonin. Chromatographic separations were achieved using gradient elution with Waters associates Symmetry C8 column (150mm x 3.9 mm; 5 mm). Mobile phase A comprised 0.1% formic acid (w/v) in deionised water, mobile phase B comprise 15% (v/v) methanol in acetonitrile containing 0.1% (w/v) formic acid. Flow rate was 0.8 mL/min with run time of 8 min. Mass spectrometer was fitted with atmospheric pressure chemical ionisation source operated in positive ion mode. Mass transitions used were 233.0 ? 173.8 for melatonin and 240 ? 178.3 for deuterated melatonin. Use of Salivettes® for saliva sample collection was assessed.

Results: The linear range was 3.9 pg/mL – 1000 pg/mL. Method reproducibility was 23.0 %, 1.6% and 1.1% at concentrations of 7.03 pg/mL, 450 pg/mL and 900 pg/mL, respectively. Accuracy was better than 97.5 %, 99.0% and 99.0% at concentrations of 7.03 pg/mL, 450 pg/mL and 900 pg/mL, respectively. Evaluation of Salivettes® shows interference when using citric acid impregnated swabs, but not with plain cotton swabs. Utility of the method has been demonstrated in a clinical application.

Conclusion: Clinical application of the method demonstrated normal circadian rhythms in healthy adult volunteers and a child with hypersomnolence. The reported assay is accurate and sensitive for use in screening children with circadian rhythm sleep disorders. It is also therefore useful for potential pharmacokinetic studies. Significant interference in the assay was encountered. This may be from melatonin in the environment.
Keyword Mass spectrometry
Melatonin
Saliva
Q-Index Code CX
Q-Index Status Confirmed Code
Institutional Status UQ

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