1 Qin S, Ferdinand A S, Richie J P, et al. Chromatofocusing fractionation and two-dimensional difference gel electrophoresis for low abundance serum proteins. Proteomics, 2005, 5: 3183-3192？？
[2]
2 Cima I, Schiess R, Wild P, et al. Cancer genetics-guided discovery of serum biomarker signatures for diagnosis and prognosis of prostate cancer. Proc Natl Acad Sci USA, 2011, 108: 3342-3347？？
5 Foote R S, Khandurina J, Jacobson S C, et al. Preconcentration of proteins on microfluidic devices using porous silica membranes. Anal Chem, 2005, 77: 57-63？？
[6]
6 Qiao X, Wang L, Ma J, et al. High sensitivity analysis of water-soluble, cyanine dye labeled proteins by high-performance liquid chromatography with fluorescence detection. Anal Chim Acta, 2009, 640: 114-120？？
[7]
7 Qiao X, Sun L, Wang L, et al. High sensitive protein detection by hollow fiber membrane interface based protein enrichment and in situ fluorescence derivatization. J Chromatogr B, 2011, 879: 1439-1443？？
[8]
8 Chiappetta G, Ndiaye S, Demey E, et al. Dansyl-peptides matrix-assisted laser desorption/ionization mass spectrometric (MALDI-MS) and tandem mass spectrometric (MS/MS) features improve the liquid chromatography/MALDI-MS/MS analysis of the proteome. Rapid Commun Mass Spetrom, 2010, 24: 3021-3032？？
[9]
9 Wang J, Zhang J, Arbogast B, et al. Tandem mass spectrometric characterization of thiol peptides modified by the chemoselective cationic sulfhydryl reagent (4-iodobutyl)triphenylphosphonium--effects of a cationic thiol derivatization on peptide fragmentation. J Am Soc Mass Spectrom, 2011, 22: 1771-1783？？
[10]
10 Mirzaei H, Regnier F. Enhancing electrospray ionization efficiency of peptides by derivatization. Anal Chem, 2006, 78: 4175-4183？？
[11]
11 Aebersold R, Mann M. Mass spectrometry-based proteomics. Nature, 2003, 422: 198-207？？
[12]
12 Qiao X Q, Wang R, Zhang L H, et al. Recent advancement of chemical derivatization and its applications to high sensitive analysis of peptide in mass spectrometry. Chin J Anal Chem, 2012, 40: 1123-1129？？
[13]
13 Kim J S, Cui E, Kim H J. Picolinamidination of phosphopeptides for MALDI-TOF-TOF mass spectrometric sequencing with enhanced sensitivity. J Am Soc Mass Spectrom, 2009, 20: 1751-1758？？
[14]
14 Kulevich S E, Frey B L, Kreitinger G, et al. Alkylating tryptic peptides to enhance electrospray ionization mass spectrometry analysis. Anal Chem, 2010, 82: 10135-10142？？
[15]
15 Laremore T N, Weber D M, Choma C T. An evaluation of the utility of in vacuo methylation for mass-spectrometry-based analyses of peptides. Rapid Commun Mass Spectrom, 2005, 19: 2045-2054？？
[16]
16 Shuford C M, Comins D L, Whitten J L, et al. Improving limits of detection for B-type natriuretic peptide using PC-IDMS: an application of the ALiPHAT strategy. Analyst, 2010, 135: 36-41？？
[17]
17 Li J, Ma H, Wang X, et al. Enhanced detection of thiol peptides by matrix-assisted laser desorption/ionization mass spectrometry after selective derivatization with a tailor-made quaternary ammonium tag containing maleimidyl group. Rapid Commun Mass Spectrom, 2007, 21: 2608-2612？？
[18]
18 Vasicek L, Brodbelt J S. Enhanced electron transfer dissociation through fixed charge derivatization of cysteines. Anal Chem, 2009, 81: 7876-7884？？
[19]
19 Arrigoni G, Resj？ S, Levander F, et al. Chemical derivatization of phosphoserine and phosphothreonine containing peptides to increase sensitivity for MALDI-based analysis and for selectivity of MS/MS analysis. Proteomics, 2006, 6: 757-766？？
[20]
20 Tsumoto H, Ra M, Samejima K, et al. Chemical derivatization of peptides containing phosphorylated serine/threonine for efficient ionization and quantification in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Rapid Commun Mass Spectrom, 2008, 22: 965-972？？
[21]
21 Xu Y, Zhang L, Lu H, et al. Mass spectrometry analysis of phosphopeptides after peptide carboxy group derivatization. Anal Chem, 2008, 80: 8324-8328？？
[22]
22 Zhang L, Xu Y, Lu H, et al. Carboxy group derivatization for enhanced electron-transfer dissociation mass spectrometric analysis of phosphopetides. Proteomics, 2009, 9: 4093-4097？？
[23]
23 Zhang J, Al-Eryani R, Ball H L. Mass spectrometry analysis of 2-nitrophenylhydrazine carboxy derivatized peptides. J Am Soc Mass Spectrom, 2011, 22: 1958-1967？？
[24]
24 Qiao X, Sun L, Chen L, et al. Piperazines for peptide carboxyl group derivatization: effect of derivatization reagents and properties of peptides on signal enhancement in matrix-assisted laser desorption/ionization mass spectrometry. Rapid Commun Mass Spectrom, 2011, 25: 639-646？？
[25]
25 Bates E D, Mayton R D, Ntai I, et al. CO2 capture by a task-specific ionic liquid. J Am Chem Soc, 2002, 124: 926-927？？
[26]
26 Pashkova A, Moskovets E, Karger B L. Coumarin tags for improved analysis of peptides by MALDI-TOF MS and MS/MS. 1. Enhancement in MALDI MS signal intensities. Anal Chem, 2004, 76: 4550-4557
[27]
27 Dreisewerd K. The desorption process in MALDI. Chem Rev, 2003, 103: 395-425？？
