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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