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Table 5 Fragmentation patterns of selective fragment ions (SFI) for trimethylsilyl and trimethylsilyl-oxime derivatives as analyzed by GC–MSa

From: Molecular and biochemical characterization of recombinant cel12B, cel8C, and peh28 overexpressed in Escherichia coli and their potential in biofuel production

Compounds Trimethylsilyl and trimethylsilyl-oxime derivatives Derivative structure Molecular weight (g/mol) Retention time (min) Selective total fragment ions (SFI) m/z a
Salicin internal standard (INSD) Salicin-5-(TMS) 633.157 INSD:9.123 73, 147, 217, 361
Citric acid (CA) Citric acid (4TMS) 480.848 CA:4.716 73, 147, 273
α- and β-d-glucopyranose
(G 1-2)
d-Glucopyranose, 1,2,3,4,6-pentakis-O-(TMS)- 541.0615 G1:5.294
G2:5.859
73, 147, 191, 204
Glucose (syn/anti-oximes)
(G 3-4)
Glucose-oxime-hexakis-(TMS) 628.2572 G3:6.042
G4:6.185
73, 147, 205, 319
α- and β-d-cellobiose
(C 1-2)
d-glucopyranose, 4-O-[1,2,3,6-tetrakis-O-(trimethylsilyl)-β-d-glucopyranosyl]- -2,3,4, 6-tetrakis-O-(trimethylsilyl)- 919.7454 C1:10.700
C2:10.855
73, 147, 204, 361
α- and β-d-Galactopyranuronic acid
(GA 1-2)
d-Galacturonic acid, O-pentakis (TMS) 555.0450 GA1:5.436
GA2:5.591
73, 147, 218
Galacturonic acid (syn/anti-oximes)
(GA 3-4)
Galacturonic acid oxime-hexakis-o- (TMS) 618.22 GA3:6.328
GA4:6.539
73, 147, 218, 333
d-galactose (Gal) Galactose oxime-hexakis (TMS) 628.2572 Gal:5.962 73, 147, 205, 319
  1. The identified derivatives represent the mono- and di-saccharide products estimated throughout a 3-h period by cel12B, cel8C, and/or peh28 during the course of hydrolysis on their respective substrates
  2. aThe mass spectra and characterization of the derivatized compounds are shown in detail in Fig. 6 for INSD, CA, G1, G2, G3, G4, C1, and C2 and Fig. 7 for GA1, GA2, GA3, GA4, and Gal. The m/z represents the masses of the fragmentation ions detected for each theoretically derivatized compound relative to the corresponding abundance in integrator units/ng (Iu/ng) as shown in Figs. 6 and 7