Simulation of Radio Frequency Quadrupole Mass Analyzer Stephen

Simulation of Radio Frequency Quadrupole Mass Analyzer Stephen Jones EPS 109 Final Project 11/27/12

Radio Frequency Mass Analyzer • Used in Mass Spectrometry to separate ions with specific mass/charge (m/z) ratio • Design: q Four electrodes with positive and negative DC voltage on diagonally opposite rods q RF AC voltage applied 180° out of phase between pairs of diagonal rods Acceleration= (charge)x(E field) /(mass) Skoog, D. ; Holler, F. ; Crouch, S. Principles of Instrumental Analysis 6 th Ed. ; Brooks/Cole; Belmont, CA 2007.

Radio Frequency Mass Analyzer - continued Both DC and AC potentials are increased during run to obtain m/z spectrum Full scan on the order of milliseconds Skoog, D. ; Holler, F. ; Crouch, S. Principles of Instrumental Analysis 6 th Ed. ; Brooks/Cole; Belmont, CA 2007.

Stable vs. Unstable Trajectories Stability is determined by Ø Dimensions of RFMA (r 0) Ø Mass (m) Ø Charge (e) Ø DC Voltage (U) Ø AC Voltage (V) Ø AC Frequency (ωrf) Stable Stability can be determined with parameters a and q Unstable F. Muntean, Int. J. Mass. Spec. Ion Proc. , 151 (1995) 197 -206

Simulation Parameters § Field radius = 3. 5 cm § Mass 1: 722. 66 Dalton § Mass 2: 57. 81 Dalton § U = ± 20 Volts § V = ± 400 Volts Molecule 1 (blue) is inside region of stability (a = 0. 04, q = 0. 4) Molecule 2 (red) is outside region of stability (a = 0. 5, q = 0. 25) Similar to: 1, 2, 3 -Tritetradecanoylglycerol http: //www. chemfinder. com/chembiofinder/Forms/Search/Content. Area/Chem. Bio. V iz. Search. aspx? Form. Group. Id=8&App. Name=CHEMBIOFINDER&Allow. Full. Search =true&Keep. Record. Count. Synchronized=false&Current. Index=1 Isopropylamine http: //www. chemfinder. com/chembiofinder/Forms/Search/Content. Area/Chem. Bio. V iz. Search. aspx? Form. Group. Id=8&App. Name=CHEMBIOFINDER&Allow. Full. Search =true&Keep. Record. Count. Synchronized=false&Current. Index=5

How to Run with script: SMJ_EPS 109_finalproj. m Function: quad. m