Experimental Report

Date of Approval 2017/5/10
Approver Kaoru Shibata
Date of Report 2017/5/10

Project No.

Name of Instrument scientist

2016B0127.

Kaoru Shibata

Title of experiment

Name of Instrument/ BL No.

Dynamics of water and glycine molecules in their DNA/BL02
mixture confined in MCM-41

Date of Experiment

Name of principal investigator

February 23, 2017 to February 27, 2017

Koji Yoshida
Affiliation
Fukuoka University

Please report your samples, experimental method and results, discussion and conclusions. Please add figures andtables for better explanation.
1.
Name of sample(s) and chemical formula, or compositions including physical form.
Samples
1. 18 wt% D-Glycine(C2H3D2NO2)/H2O solutions at pH=2 confined in MCM-41 C18
2. 18 wt% D-Glycine(C2H3D2NO2)/H2O solutions at pH=5 confined in MCM-41 C18
3. 18 wt% H-Glycine(C2H2D3NO2)/D2O solutions at pH=2 confined in MCM-41 C18
4. 18 wt% H-Glycine(C2H2D3NO2)/D2O solutions at pH=5 confined in MCM-41 C18
The hydration levels (mass of glycine / mass of dry MCM-41) of all samples are 0.6.

2.
Experimental method and results.

If you failed to conduct experiment as planned, please describe reasons.

Experimental method
Vacuum dried MCM-41 C18 powder (pore diameter is 32 Å) and 18 wt% glycine aqueous solution at pH=5 and2 were put in Eppendorf tubes, and the mixtures were stirred for about 1 h using a vortex mixer. The powdery
samples were wrapped with aluminum foil in a thin plate-like shape were inserted into a double cylindricalaluminum cell, which consist of cylinder of 18.0 mm outer diameter, 0.25 mm thickness, and 50 mm height. Thethickness of samples was 2~4 mm, depending on the transmission of samples (more than 90 %). These cells weresealed with indium. The measurements were performed at 305, 290, 275, 260 and 245 K.
Results
Fig. 1 shows the temperature dependence of QENS spectra of 18 wt% D-glycine solution at pH=5 confined in
MCM-41 at Q=1.0 Å-1. The individual spectra are shifted for clarity. The instrumental resolution function wasmeasured at 100 K since any motion of water molecules can be regarded as a standstill on the time scale of thisspectrometer. QENS spectra were fitted by a Lorentzian function and a delta function.

2.

Experimental method and results (continued)
Fig. 2 shows the fitting results of the half

40305 K+32290 K+2420 275 K+18260 K+8width half maximum (HWHM), (Q), by a jump30

diffusion model for 18 wt% D-glycine solution
confinedinMCM-41.

The

self-diffusion

coefficient, D, and the residence time, , wereobtained from this model.

10245 K
0-20-10010
Energy transfer / eV

Fig. 3 shows the Arrhenius plots of D for
glycine solutions confined in MCM-41. The20Fig. 1. The temperature dependence of QENS spectra ofactivation energies of D-glycine at pH=5,18 wt% D-glycine solution at pH=5 confined in
MCM-41 C18 at Q = 1.0 Å-1.

D-glycine at pH=2, H-glycine at pH=5 andH-glycine at pH=2 solutions confined in
MCM-41 C18 were 21.3, 24.5, 20.7 and 17.1
kJ/mol, respectivery. The values for H-glycine
solutions could reflect the activation energy of the20translatonal motion of glycine molecules since theneutrons scattering cross section of H is muchlarger than that of the other atoms. The results
indicatethattheactivationenergyof305 K290 K275 K260 K245 K

10

thetranslational motion of glycine moelcuels at pH=5was larger than that at pH=2. It is consisttent with
the X-ray diffraction results which indicate that theglycine molecules locate near the silica surface byforming

theNH3CH2COO-hydrogenbondof-Si at pH=5.

0012Q

23-2

Fig. 2. Q-dependence of HWHM of Lorentzian function
for 18 wt% D-glycine solution at pH=5 confined in
MCM-41 C18 at 305, 290, 275, 260 and 245 K. Thesolid lines are fitting results by a jump diffusion model.

On the other hand, the activation energy for
D-glycine solutions could reflect that of the

5D-glycine pH=5D-glycine pH=2
H-glycine pH=5
H-glycine pH=2

translational motion of water molecules. X-ray
diffraction results imply that glycine molecules
locate in the pore center at pH=2. Hence, glycine

4molecule could be hydrated at pH=2 more strongly.
That is why the activation energy of the3translational motion of water molecules at pH=2
was larger than that at pH=5.

3.4

Fig.

3.

3.6-1
T

Arrhenius

3.8
-1
/K-3

plotof4

4.2

self-diffusion

coefficient D for 18 wt% glycine solution
confined in MCM-41 C18.