Biogenic @entity4478 are interesting compounds which may be of use for medical diagnosis or therapeutic monitoring. The present paper deals with the problems that occur with concentration determination of @entity9903 ( @entity3496 ) and @entity12680 ( @entity10226 ). These occur in the breath of @entity1 suffering from @entity8 . The measurement of @entity4478 present in trace concentrations requires the application of suitable analytical methods during sampling, storage and preconcentration. This is particularly so due to their polar and basic properties. In this paper, the application of solid phase microextraction (SPME) and @entity1931 ( @entity1931 ) with subsequent measurement by GC-MS for the determination of @entity4478 is discussed. For @entity3496 , preconcentration by SPME did not give satisfactory results. @entity10226 may be analysed using SPME preconcentration with an LOD of 1.5 ppb. Thermal desorption with Tenax as the adsorbing material allows reliable concentration determination for @entity10226 (LOD = 0.5 ppb) and @entity3496 (LOD = 4.6 ppb). @entity3496 cannot be stored reliably in Tedlar bags and longer storage on Tenax (with subsequent @entity1931 ) does not give good repeatability of results. For @entity10226 , storage can be done on Tenax or in bags, the best results for the latter being achieved with Flex Foil bags.

Application of GC-MS with a SPME and @entity1931 technique for determination of XXXX and @entity12680 in gaseous samples for medical diagnostic purposes.

@entity1 :: ('9606', 'Species') :: ['people'] @entity12680 :: ('MESH:C023336', 'Chemical') :: ['trimethylamine'] @entity8 :: ('MESH:D007674', 'Disease') :: ['renal disease'] @entity3496 :: ('MESH:C405765', 'Chemical') :: ['DMA'] @entity1931 :: ('MESH:D006930', 'Disease') :: ['TD', 'thermal desorption'] @entity10226 :: ('CHEBI:166055', 'Chemical') :: ['TMA'] @entity9903 :: ('MESH:C034516', 'Chemical') :: ['dimethylamine'] @entity4478 :: ('MESH:D000588', 'Chemical') :: ['amines']
@entity9903 :: (MESH:C034516,Chemical) :: ['dimethylamine']
