Dipotassium edta tubes

Adenosine, Adenosine Monophosphate (AMP), Adenosine triphosphate (ATP), Guanosine, Guanosine monophosphate (GMP), guanosine triphosphate (GTP), Inosine, Inosine monophosphate (IMP), and Inosine triphosphate (ITP) were purchased from Sigma Aldrich, St. Louis, MO; isotopic internal standards for each, (Ribose ¹³C₅) were from Cambridge Isotope Laboratories, Andover, MA.
Analytical grade reagents were purchased from Fisher Scientific, Fairlawn, NJ, (acetonitrile, methanol, formic acid, potassium chloride, phosphoric acid, and ammonium hydroxide) as well as Whatman^® 903 DBS cards, bags and desiccant for DBS preparation and storage. Ammonium acetate 5M solution was purchased from Ambion® and alkaline phosphatase was purchased from Sigma Aldrich, St. Louis. Ultrapure (UP) water was prepared in house from deionized water with a Barnstead Nanopure System (Thermo Fisher Scientific, Waltham, MA). Other supplies included Waters Sep-Pak Accell Plus QMA Cartridge, 3cc (500mg) (Waters Corporation, Milford, MA) and Varian Bond-Elut LRC Phenylboronic Acid (PBA) Cartridge 100mg/10mL (Agilent, Santa Clara, CA). Blood products for lysed cellular matrix were obtained from Bonfils, Denver CO. Cell preparation tubes (CPT) and dipotassium EDTA tubes were purchased from Becton, Dickinson and Company, Franklin Lakes, NJ.