Quick Reference for Practical Implementation of the Methodology

As mentioned, the number of published analytical protocols is in the same order of magnitude as the number of papers that has appeared on this specific topic. Each researcher has slightly or deeply modified his own method and, for experience of 

Hereby we present a trace, reflecting somehow the original format, which should be a good starting point for any newcomer in this technology. Vessel types are proposed for beginners and for minute-scale assays in routine they are swapped to 96-well hter plates. 

A circle 3 mm in diameter (roughly corresponding to 3 fxL of original blood) is punched out from each spot by means of a standard hole puncher into 1.5 mL polypropylene tube. Specimen is pricked-heel blood subsequently dried on Schleicher Schuell filter paper (in Europe Grade 903 is used at the most). 

The spot is treated at room temperature for 20 min with methanol (200 fxL) containing known amounts of stable-isotope-labeled internal standards for AA and AC as commercially available in a cocktail. The supernatant liquid, containing the sample extract, is transferred to glass autosampler vial (screw-capped). 

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