TY - JOUR
T1 - Measurement of acetylcholine in rat brain microdialysates by LC-isotope dilution tandem MS
AU - Prokai, Laszlo
AU - Fryčák, Petr
AU - Stevens, Stanley M.
AU - Nguyen, Vien
N1 - Funding Information:
Financial support for this work was provided in part by the grant RR12023 from the National Institute of Health (Bethesda, MD, USA). Laszlo Prokai is the Robert A. Welch Professor of the University of North Texas Health Science Center.
PY - 2008/10
Y1 - 2008/10
N2 - An LC-MS-MS method was developed for measuring acetylcholine (ACh) in an aqueous medium using reversed-phase ion-pair chromatography, electrospray ionization on a quadrupole ion trap instrument and a tetradeuterated analogue (ACh-1,1,2,2-d4) as an internal standard. A rapid separation was achieved on a 5-cm long octadecylsilica column (2.1 mm i.d.) by employing heptafluorobutyric acid (0.1% v/v) as an ion-pairing agent and requiring 10% v/v acetonitrile in 20 mM ammonium formate buffer under isocratic elution at 200 μl min-1 flow rate. The instrument's response was calibrated with samples containing known mole ratios of ACh and ACh-1,1,2,2-d4 in an artificial cerebrospinal fluid, which afforded the conclusion that analyte concentrations could be determined by multiplying the measured analyte to internal standard ion-current ratio with the known molar concentration of the ACh-1,1,2,2-d4 added. The rapid and simple assay was tested by measuring the basal neurotransmitter concentration in rat brain microdialysates without the use of a cholinesterase inhibitor upon sample collection.
AB - An LC-MS-MS method was developed for measuring acetylcholine (ACh) in an aqueous medium using reversed-phase ion-pair chromatography, electrospray ionization on a quadrupole ion trap instrument and a tetradeuterated analogue (ACh-1,1,2,2-d4) as an internal standard. A rapid separation was achieved on a 5-cm long octadecylsilica column (2.1 mm i.d.) by employing heptafluorobutyric acid (0.1% v/v) as an ion-pairing agent and requiring 10% v/v acetonitrile in 20 mM ammonium formate buffer under isocratic elution at 200 μl min-1 flow rate. The instrument's response was calibrated with samples containing known mole ratios of ACh and ACh-1,1,2,2-d4 in an artificial cerebrospinal fluid, which afforded the conclusion that analyte concentrations could be determined by multiplying the measured analyte to internal standard ion-current ratio with the known molar concentration of the ACh-1,1,2,2-d4 added. The rapid and simple assay was tested by measuring the basal neurotransmitter concentration in rat brain microdialysates without the use of a cholinesterase inhibitor upon sample collection.
KW - Acetylcholine
KW - Column liquid chromatography-tandem mass spectrometry
KW - Electrospray ionization
KW - In vivo intracranial microdialysis
KW - Isotope dilution
UR - http://www.scopus.com/inward/record.url?scp=54849427465&partnerID=8YFLogxK
U2 - 10.1365/s10337-008-0697-0
DO - 10.1365/s10337-008-0697-0
M3 - Article
AN - SCOPUS:54849427465
SN - 0009-5893
VL - 68
SP - S101-S105
JO - Chromatographia
JF - Chromatographia
IS - SUPPL. 1
ER -