Original Paper

Analytical and Bioanalytical Chemistry

, Volume 388, Issue 8, pp 1643-1651

First online:

Autism and urinary exogenous neuropeptides: development of an on-line SPE–HPLC–tandem mass spectrometry method to test the opioid excess theory

  • K. DettmerAffiliated withInstitute of Functional Genomics, University of RegensburgDepartment of Entomology, University of California at Davis Email author 
  • , D. HannaAffiliated withDepartment of Entomology, University of California at Davis
  • , P. WhetstoneAffiliated withDepartment of Entomology, University of California at Davis
  • , R. HansenAffiliated withDepartment of Pediatrics, M.I.N.D. Institute, University of California Davis School of Medicine
  • , B. D. HammockAffiliated withDepartment of Entomology, University of California at Davis

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Autism is a complex neurodevelopmental disorder with unknown etiology. One hypothesis regarding etiology in autism is the “opioid peptide excess” theory that postulates that excessive amounts of exogenous opioid-like peptides derived from dietary proteins are detectable in urine and that these compounds may be pathophysiologically important in autism. A selective LC–MS/MS method was developed to analyze gliadinomorphin, β-casomorphin, deltorphin 1, and deltorphin 2 in urine. The method is based on on-line SPE extraction of the neuropeptides from urine, column switching, and subsequent HPLC analysis. A limit of detection of 0.25 ng/mL was achieved for all analytes. Analyte recovery rates from urine ranged between 78% and 94%, with relative standard deviations of 0.2–6.8%. The method was used to screen 69 urine samples from children with and without autism spectrum disorders for the occurrence of neuropeptides. The target neuropeptides were not detected above the detection limit in either sample set.


Autism Neuropeptides β-Casomorphin Gliadinomorphin Opioid peptide excess theory On-line SPE–HPLC–MS/MS