Journal of chromatography. A
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Exhaled breath condensate (EBC) is receiving increased attention as a novel, entirely non-invasive technique for collecting biomarker samples. This increased attention is due to the fact that EBC is simple, effort independent, rapid, can be repeated frequently, and can be performed on young children and patients suffering from a variety of diseases. By having a subject breathe tidally through a cooling system for 15-20 min, a sufficient amount of condensate is collected for analysis of biomarkers in clinical studies. ⋯ To demonstrate the liquid chromatography with hydrophilic interaction with electrospray source coupled to tandem mass spectrometry (LC-HILIC-ESI-MS/MS) method's applicability for biomedical investigations, it was verified and applied to determine amino acids in pediatric patients with leukemia. These tests confirmed that glutamine, arginine, homoarginine, asparagine, histidine, methionine, proline, hydroxyproline, threonine, tyrosine, and valine were present in significantly higher levels in pediatric leukemia patients than in the healthy control group. The developed assay is an attractive alternative to standard analytical methods, because it allows for the non-invasive, fast, sensitive, and reliable analysis of amino acids without derivatization in EBC.