Author(s)

Syed Ghulam Musharraf, Aisha Bibi, Najia Shahid, Muhammad Najam-ul-Haq, Momin Khan, Muhammad Taha, Uzma Rasool Mughal, Khalid Mohammed Khan

Department of Chemistry, Bahauddin Zakariya University, Multan, Pakistan.
Hussain Ebrahim Jamal Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan.
Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, Pakistan.

Matrix-assisted laser desorption/ionization (MALDI) is a preferred and widely used mass spectrometric technique for the analysis of macromolecules. Limited UV-LDI matrices are available for the analysis of biomolecules due to the restricted structural features to serve in the laser desorption/ionization mechanism with a problem of background signals appearing in the low mass region. This paper describes the application of Schiff base derivatives of acylhydrazide and isatin as alternate UV-LDI matrices for the analysis of peptides with significantly low background signals. Thirty one compounds have been successfully employed as matrices for the analysis of low molecular weight (LMW) peptides (<2000 Da) including bradykinin and renin substrate tetra-decapeptide. Bovine serum albumin (BSA)-digest was also analyzed and identified through database search against Swiss-Prot by using MASCOT. The MS measurements were recorded by using dried droplet sample preparation procedures by mixing the matrix solution with analyte at a volume ratio of 1:2. Finally, LMW organic compounds (<500 Da) were also analyzed by the synthesized matrix materials which showed better S/N ratios and minimal background signals for low mass range in comparison to the comparable results with α-Cyano-4-hydroxycinnamic acid (HCCA), a preferred choice for peptide analysis.

MALDI-MS; LDI Matrix; Acylhydrazide Schiff Bases; Bis-Schiff Bases of Isatin; Schiff Bases of Isatin; Peptides

S. Musharraf, A. Bibi, N. Shahid, M. Najam-ul-Haq, M. Khan, M. Taha, U. Mughal and K. Khan, "Acylhydrazide and Isatin Schiff Bases as Alternate UV-Laser Desorption Ionization (LDI) Matrices for Low Molecular Weight (LMW) Peptides Analysis," American Journal of Analytical Chemistry, Vol. 3 No. 12, 2012, pp. 779-789. doi: 10.4236/ajac.2012.312104.