Screening for amino acids

In metabolism, more specifically newborn screening for amino acids and acyl-carnitines, we use two other types of MS/MS analyses the precursor and neutral loss scans. In both types of scan, the question is asked where did I come from In other words, a fragment of a molecule is detected that is unique or common to a particular molecule or family of structurally similar molecules. Because the instruments are linked in space rather than time, when a particular product is detected in the second mass spectrometer (MS2), the computer software knows what mass was being scanned in the first mass spectrometer (MSI). The difference between a precursor ion and neutral loss scan is the nature of the product. With a precursor ion scan, that product of interest is also an ion and it can be detected. With a neutral loss... 

Clift, J., Hall, S. K., Carter, R. A., Denmeade, R., and Green, A. (1994). An improved thin-layer chromatography technique for neonatal screening for amino acid disorders using dried blood spots. Screening 3 39-43. 

Routine metabolic screening for amino acid disorders usually includes several simple general preliminary tests and chromatographic analysis of amino acids. Because of the wide availability of amino acid analyzers, semi-quantitative amino acid screening is now used less often. One-dimensional paper or thin-layer chromatographic screening for amino acids is... 

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