Selective Enrichment and MALDI-TOF MS Analysis of Small Molecule Compounds with Vicinal Diols by Boric Acid-Functionalized Graphene Oxide
Jing Zhang*, Xiaoling Zheng,Yanli Ni
Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710062, China
*Correspondence author: Jing Zhang, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710062, China
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SUPPLEMENTARY INFORMATION
FIGURE CAPTIONS
1. SupplementaryFigure 1 (S1).FTIR spectra of GO, GO-Br and GO-VPBA.
2. SupplementaryFigure2 (S2).XPS spectra of GO, GO-Br and GO-VPBA.
3. SupplementaryFigure3 (S3).Effects of the amount of grafting VPBA to the MS intensity.
4. SupplementaryFigure4(S4).Effects of pH on the MS intensity.
5. SupplementaryFigure5(S5).MALDI mass spectra of adenosine, guanosine, uridineandcytidine before and after enriched by GO-VPBA.
7. Supplementary Table1(TableS1). The structuresof compounds with and withoutvicinaldiols.
8. SupplementaryFigure6(S6). MALDI mass spectrum of GO-VPBA.
Optimization ofthe amount of grafting VPBAforMALDI-TOFMS analysis.
1.0 mg of GO-VPBA1, GO-VPBA2, GO-VPBA3 and GO-VPBA4 were suspended in 1.0 mL of water/ethanol (1:1, v/v) with sonication, respectively. 1.0 mg/mL of adenosine and guanosine were dispersed in PBS at alkaline pH, respectively. GO-VPBA suspension (GO-VPBA1, GO-VPBA2, GO-VPBA3 or GO-VPBA4) and solution of analyte (adenosine or guanosine) were mixed (1:1, v/v), respectively, making them to disperseevenly with sonication, then they (1μL) were pipetted onto the MALDI target, respectively. After evaporation of the solvent, the sample was subjected to MALDI-TOFMS analysis.
Effects of the amount of grafting VPBA to the MS intensity.
The amount of VPBA grafted(Fig.S2)were optimizedfor better enrichment efficiency and stronger mass spectrum signal.Itwas illustrated that the amount of thegrafting VPBA has a little effect on MS signal due to when using GO-VPBA2 as the MALDI matrix,the MS intensity gradually stabilized, but it still has a tendency to increase untilusing GO-VPBA3 as the MALDI matrix.
Details on recovery experiments.
1.0 ng mL-1 adenosine, guanosine and cytidine were dispersed in 100μL of the urine sample solution with 1.0 ng uridine (IS), respectively. Then there copies of 100 μL of GO-VPBA (1.0 mgmL-1) were added intothe above solutions, respectively. The mixtures were then sonicated for 30 min, respectively. These mixtures were separated by centrifugation at 9000 rpm for 10 min, the supernatant was removed, and the GO-VPBA pellet was washed with 100 µL of water. The pellet was centrifuged at 9000 rpm for 10 min, the supernatant was removed, and the resulting GO-VPBA pellet enriched with analytes was wash with100 µL acetonitrile. Finally, the eluted solution was concentrated to dryness andre-dispersed in a 2 μL solution of ethanol. Finally, the solution was mixed with 2 μL of the GO-VPBAsolution and then1 μL suspension was pipetted onto the target sample for further analysis by MALDI-TOF MS. The recoveries were obtained by the analyte's concentration ratios about calculation and addition.
Figure S1. FTIR spectra of GO, GO-Br and GO-VPBA.
Figure S2.XPS spectra of GO, GO-Br and GO-VPBA.
Figure S3.Effects of the amount of grafting VPBA to the MS intensity.
Figure S4. Effects of pH on the MS intensity.
Figure S5.MALDI mass spectra of adenosine (1), guanosine (2), uridine (3) andcytidine (4) before and after enriched by GO-VPBA.
TableS1The structuresof compounds withand withoutvicinaldiols.
The structuresof compoundsCompounds withvicinaldiols /
Adenosine Guanosine Cytidine
Galactose Glucose Catechol
Compoundswithoutvicinaldiols /
Guanine Adenine Diethylstilbestrol
Phenol Xylose Resorcinol
Figure S6. MALDI mass spectrum of GO-VPBA.
S1