Mixed Solvent Of Dimethyl Sulfoxide Research Articles

A thermo-responsive hydrogel for body temperature-induced spontaneous information decryption and self-encryption.

A thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) hydrogel, exhibiting an interesting phenomenon of an opaque-transparent-opaque transition in the successive processes of heating and cooling, is reported. It is fabricated by means of both the porogenic effect of hydroxypropyl cellulose and the cononsolvency effect of PNIPAM in a mixed solvent of dimethyl sulfoxide and water. After being mildly triggered by body temperature, the hydrogel is used to spontaneously decrypt the quick response code within 4 min and then autonomously encrypts the code again within 10 min at room temperature. The mechanism for the transient transparency of hydrogels during the quenching process has been elucidated.

Preparation of a novel poly-(di-ionic liquid)/BDD-modified electrode for the detection of tetrachloro-p-benzoquinone

During the COVID-19 pandemic, the release of toxic disinfection by-products (DBPs) has increased due to the intensive, large-scale use of disinfectants. Halogenated benzoquinones (HBQs) are among the most toxic DBPs, but there is no rapid, convenient, and economical detection method. In this study, a novel PDIL/BDD-modified electrode was prepared in a mixed solvent of dimethyl sulfoxide (DMSO) and acetonitrile (ACN) by electrochemical polymerization with a di-ionic ionic liquid containing alkenyl groups as the monomer. The electrochemical behavior of tetra-chloro-p-benzoquinone (TCBQ) on the modified electrode was studied. By studying the cyclic voltammetry behavior of TCBQ on the PDIL/BDD electrode, it was concluded that the electrode reactions of TCBQ included the reduction of TCBQ to TCBQH2 (C1) and the reduction of bis-quinhydrone imidazole π-π type charge transfer complex to TCBQH2 (C2). By studying the SWV responses of TCBQ in the concentration range of 1–100 ng/L on the PDIL/BDD electrode, it was found that the reduction peak current (Ipa) had a linear relationship with the concentration. The electrochemical SWV technique was used to detect the concentration of trace TCBQ in water and is expected to be used for the detection of other HBQs in drinking water and swimming pool water.

Preparation and characterization of high strength and high modulusPVAfiber via dry‐wet spinning with cross‐linking of boric acid

AbstractTo improve the mechanical properties of polyvinyl alcohol (PVA) fibers, a series of PVA fibers were prepared via dry‐wet spinning with cross‐linking of boric acid (BA) (PVA/BA fibers), and using the mixed solvent of dimethyl sulfoxide and water. Moreover, the final PVA/BA fibers were characterized by Fourier transform infrared spectra (FTIR), scanning electron microscopy (SEM), differential scanning calorimetery (DSC), thermogravimetric analyzer (TGA), powder X‐ray diffraction (XRD) and yarn strength tester. Furthermore, with the increasing of BA content, FTIR analysis showed that the degree of crosslinking of BA with PVA increased. SEM images of final PVA/BA fibers presented smooth surfaces, and the diameters decreased firstly and then increased. DSC, TGA, and XRD analysis indicated that the melting temperatures, thermal properties and crystallinities first increased and then decreased with the increasing of BA content. In addition, mechanical properties measurements illustrated that the cross‐linking existed at an optimal BA content of 0.3 wt%, and PVA/BA‐0.3 fiber had the highest tensile strength and Young's modulus of 13.1 ± 0.4 and 360.2 ± 10.4 cN/dtex, respectively.

Mixed solvent atmosphere induces the surface termination state transition of perovskite to achieve matched energy level alignment

The optimal alignment of semiconductor's electronic energy level with respect to hole-transporting materials (HTMs and ETMs) determines the photovoltaic conversion efficiency of perovskite solar cells (PSCs). The energy level of perovskite can be greatly affected by the crystal surface termination state formed in the perovskite polycrystalline film preparation process. Perovskite featured with Pb-X termination always bears deep energy level which cannot match well HTM. Herein, to regulate the surface termination state of the perovskite crystals, a controlled solvent atmosphere dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) was employed to induce the regrowth of perovskite crystals. Results prove that the mixed solvent of DMSO and DMF can induce perovskite crystals from Pb-X termination to A-X termination. Density functional theory (DFT) calculations show that the terminated conversion moves the valence and conduction band edge (VBE and CBE) of perovskite crystal to a shallower energy level, which does great favor to match the energy level of HTM, and then contributes to extracting charges. In addition, the defect density of the optimized perovskite polycrystalline film decreased from 1.258 × 1016 to 1.022 × 1016 cm -3, and the depletion width of PSCs increased from 48.9 to 56.1 nm. Profiting from the effective charge extraction and reduced non-radiative recombination, the open circuit voltage of the PSC increased from 0.99 to 1.09 V, and the conversion efficiency boosted from 17.8% to 20.3%..

Fully slot-die-coated perovskite solar cells in ambient condition

Organic–inorganic hybrid perovskite solar cells (PSCs) are developing rapidly, but most of the PSCs are prepared by spin coating process, which is not compatible with potential large-scale, high-throughput industrialization. Slot-die coating is a promising deposition technique with high precision and excellent material utilization, which can accelerate the industrial-scale production of PSCs and enhance the potential commercial value. Herein, fully slot-die-coated PSCs were achieved by subsequently slot-die coating electron transport layer, perovskite layer and hole transport layer in ambient condition, leading to a power conversion efficiency (PCE) up to 14.55%. The optimization of slot-die coating parameters for two-step deposition process can produce even PbI2 film and subsequent high-quality perovskite film. Furthermore, a mixed solvent of dimethyl sulfoxide and N, N-dimethylformamide was used to dissolve PbI2 for further enhancing the surface energy and delaying crystallization, leading to a uniform and better perovskite film. In addition, the slot-die coating properties and repeatability could be improved by adding a small quantity of cations (cesium, methylammonium and formamidinium) additives into the PbI2 precursor solution. The results suggest that efficient PSCs with good repeatability could be processed via fully slot-die coating in ambient condition, which is compatible with potentially large-scale, roll-to-roll commercial process.

Ion-Implanted Photoresist Stripping by Using Organic Solvents

In the ion implantation process, accelerated ions attack not only target materials but also photoresist, causing deformation of the molecular structure of the photoresist. It is difficult to remove crust layer formed by ion implantation in the standard photoresist removal methods. A typical method of removing high-dose ion-implanted photoresist is to use plasma ashing followed by the treatment in the mixture of hot sulfuric acid and hydrogen peroxide [1]. However, this process etches III-V semiconductors and dielectric materials [2]. Therefore, in this study, organic solvent-based mixtures were developed to remove high-dose ion-implanted photoresist without damaging the substrate. Trench-patterned GaAs was used as a substrate and KrF photoresist was coated on trench patterned GaAs. Then, P+ ion implantation with a dose of 5×1015 ions/cm2 was conducted on the photoresist. A mixed solution of dimethyl sulfoxide (DMSO) and acetonitrile (AcN) (DMSO: AcN = 6: 4) was used to remove the ion-implanted photoresist and 1 vol% HCl or HF was used as an additive. Photoresist removal was measured using an optical microscope and in-situ MIR-FTIR. When a mixed solvent of DMSO and AcN was used to remove ion-implanted photoresist, the photoresist was not completely removed and the residue and crust remained on the trench-pattern (Fig. 1). In order to improve the removal efficiency of ion-implanted photoresist, 1 % HCl or HF was added to DMSO+AcN solution. When 1 % HCl was added to the DMSO+AcN solution, the ion-implanted photoresist with an implantation energy of 30 and 50 keV was completely removed without residue. However, when the ion implantation energy was 70 keV, the photoresist crust was not removed in DMSO+AcN+HCl solution. When 1 % HF was added to DMSO+AcN solution, the ion-implanted photoresists was completely removed regardless of the ion implantation energy. Removal performance was quantitatively analyzed by in-situ MIR-FTIR as shown in Fig. 2. First, the ion-implanted photoresist was not removed more than 40 % for 10 min in DMSO. In DMSO+AcN solution, most of the photoresist was removed in 6 min, and all photoresist was removed in 4 min when DMSO+AcN+HCl was used. In the case of DMSO+AcN+HF, all of the ion-implanted photoresists were completely removed in 2 min and 30 s. Therefore, it is confirmed that DMSO+AcN+HF solution removes ion-implanted photoresist more quickly and effectively than other solutions used in this study. In addition, it is suggested that the largest interaction energy between DMSO+AcN+HF and the ion-implanted photoresist resulted in improvement of the removal efficiency of the photoresist.

Improvement of the Non-aqueous Titration Method in the Japanese Pharmacopoeia for a Purpose of Advancement in Experimental Safety Using Alternative Solvents

In this study, we attempted to improve the non-aqueous titration method using N,N-dimethylformamide (DMF) in the Japanese Pharmacopoeia seventeenth edition (JP XVII) for advancement in experimental safety. As an alternative solvent for DMF, we demonstrate titrations using dimethyl sulfoxide (DMSO), which has similar properties as and much higher safety than DMF. Five drugs (i.e., acetohexamide, glibenclamide, sulfamethoxazole, tranilast, and furosemide) listed in JP XVII use DMF as a solvent for titrations with sodium hydroxide standard solution. For these drugs, we examined whether DMF can be replaced with DMSO in quantitative analyses. As a result, a quantification similar to that of the Pharmacopoeia protocol is possible by simply replacing DMF with DMSO or using a mixed solvent of DMSO and water.

Control of a Ternary Extractive Distillation Process with Recycle Splitting Using a Mixed Entrainer

Dynamic control of the ternary extractive distillation process is complex, due to the relatively high number of operating parameters and interactions between multiple azeotropes. In this research, the control structures of the ternary extractive distillation using dimethyl sulfoxide and a mixed solvent of dimethyl sulfoxide and ethylene glycol, as the entrainer, were explored for separating tetrahydrofuran/ethanol/water. A composition with a ratio of reboiler duty to mole feed flow rate control structure was proposed to obtain good dynamic responses for the ternary extractive distillation process with dimethyl sulfoxide and mixed entrainer. Moreover, control comparisons of the ternary extractive distillation with dimethyl sulfoxide and mixed entrainer demonstrated that the dynamic performances of the extractive distillation with mixed entrainer were better compared with the process using dimethyl sulfoxide. These studies contribute to the development of controllability for ternary extractive distillation ...

Evaluation of physical property for syndiotactic PVA-H by hot pressing method

Event Abstract Back to Event Evaluation of physical property for syndiotactic PVA-H by hot pressing method Tomoyo Sakaguchi1, Shusaku Nagano2, Mitsuo Hara3, Yoshihiro Kimura4, Akinobu Oharuda4 and Kazuaki Matsumura1 1 Japan Advanced Institute of Science and Technology, School of Materials Science, Japan 2 Nagoya University, The Nagoya University Venture Business Laboratory, Japan 3 Nagoya University, Graduate School of Engineering, Japan 4 JAPAN VAM & POVAL CO.,LTD., Reserch and Developement Dept., Japan Introduction: We have investigated poly(vinyl alcohol) (PVA) hydrogel as a biomaterial for a replacement for artificial articular cartilage because of its excellent mechanical properties, biocompatibility, and low friction coefficient[1],[2]. PVA hydrogels are physical gels with small crystalline as crosslinking points and have been prepared by low temperature crystallization method[3]. In order to prepare PVA hydrogels having high mechanical properties, a mixed solvent of dimethyl sulfoxide (DMSO) and water should be used to prevent freezing of the solvent and phase separation during freezing. In our previous study, we successfully prepared transparent PVA hydrogel without using toxic DMSO from high concentrated PVA aqueous solution by hot pressing method[4]. In this study, we intended to prepare mechanically stronger hydrogels from syndiotactic PVA (s-PVA) by using hot pressing method because s-PVA is difficult to be dissolved in water by usual heating and stirring method due to its high crystallinity. Material and Methods: In hot pressing method, atactic PVA (a-PVA) or s-PVA (Japan VAM & POVAL Co. Ltd., degree of polymerization 1700, degree of saponification 99.0%), [s]-traid value, a-PVA : 30%, s-PVA : 36%) was mixed with H2O at a concentration of 40 w/w%. The swollen PVA/H2O was pressed at 0-20 MPa and 95-130 oC for 30 min, then kept at room temperature without drying for gelation one week. After 2 days vacuum drying, gels were heated in vacuum to control the water content. While gelation time, we conducted tensile test to evaluate the gelation speed of each PVA hydrogel from Young’s modulus. And we also measured small angle X-ray scattering (SAXS) to evaluate the developing speed of crystalline in PVA hydrogel. Results and Discussion: By hot pressing method, transparent hydrogels were obtained with s-PVA, because of the fast crystallization, even at room temperature. Fig 1. Syndiotactic PVA hydrogel by hot pressing method Water content was well controlled by heating of dried gel due to the increasing of crystallinity. When we use a-PVA, around 35 % is minimum water content. But when we use s-PVA, we succeeded in preparing around 30 % water content PVA hydrogel. Tensile test revealed that s-PVA hydrogel showed higher Young’s modulus in each gelation time, showing faster gelation than a-PVA hydrogel . Fig 2. Time dependence of Young’s modulus during gelation time Faster crystallization in s-PVA was confirmed by SAXS measurement. It revealed that diffraction peak in s-PVA hydrogel appeared at one day after preparation. On the other hand, diffraction peak of a-PVA, appeared at 30 days after preparation. Conclusion: By using s-PVA, we succeeded in preparing transparent PVA hydrogel with higher mechanical property and lower water content than a-PVA. And s-PVA hydrogel showed faster gelation and crystallization time than a-PVA hydrogel. From these results, mechanically robust hydrogel which might be suitable for the articular cartilage implant could be developed by using hot pressing method and s-PVA.

Fine regulation of cellulose dissolution and regeneration by low pressure CO2 in DMSO/organic base: dissolution behavior and mechanism.

In this study, the fine regulation of the dissolution and regeneration of microcrystalline cellulose (MCC) using very low pressure (0-0.2 MPa) CO2 in a mixed solvent of dimethyl sulfoxide (DMSO) and 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) at a very low temperature (30 °C) was achieved. The solubility of MCC in DMSO/DBU (weight ratio of DMSO WDMSO = 0.90) could reach 9.0% at 30 °C and under CO2 pressure of 0.2 MPa. A similar phenomenon was observed in the mixed solvent DMSO/1,1,3,3-tetramethylguanidine (TMG). Moreover, ATR-FTIR, NMR, UV-Vis, TGA, XRD and DFT computational analyses were used to investigate the dissolution mechanism. It was concluded that in the mixed solvent (DMSO and organic base), DMSO helped to dissociate ion-pairs into free ions by balancing the concentration of free ions and the number of hydrogen bonds at WDMSO = 0.90. Interactions between CO2 and the solvent mixture were explored, and the results indicate that the optimum CO2 pressure not only promotes the formation of ionic bonds but also accelerates the formation of covalent bonds. In this way, these interactions prevent the MCC molecules from aggregating and facilitate the dissolving of MCC. This study gives a thorough insight into the dissolution mechanism and specificity of MCC in the CO2-DMSO/organic base solvent system, which could be helpful for the utilization and transformation of cellulose.

Hydrogel formation from the concentrated aqueous solution of polyvinyl alcohol

ABSTRACTPhysically crosslinked polyvinyl alcohol (PVA) hydrogels with high mechanical properties can be made by a low temperature crystallization method using a mixed solvent of dimethyl sulfoxide (DMSO) and water. Such hydrogels are studied as the artificial articular cartilage material. But DMSO shows cytotoxycity, and it is also have the effect of accelerating the absorption of harmful substances. Therefore completely elimination must be required for clinical application but the process is difficult.However, PVA hydrogel made by water as a sole solvent by freeze-thawing method became cloudy because of micro-heterogeneous structure, and shows low mechanical properties.Therefore, in this study, we developed the novel hot pressing method for preparing transparent and uniformly cross-linked PVA hydrogels without DMSO from highly concentrated aqueous solution. By this method, PVA hydrogels with high mechanical property and high transparency can be obtained without any harmful organic solvent because of the fast crystallization even at room temperature. The mechanical properties of PVA hydrogels were remarkably depended on their water contents after gelation, regardless of solution concentration.

Vapor–liquid phase equilibrium of carbon dioxide with mixed solvents of DMSO + ethanol and chloroform + methanol including near critical regions

A visual and volume-variable high-pressure phase equilibrium analyzer was used for measuring the vapor–liquid phase boundaries of the ternary systems containing carbon dioxide and mixed solvents of dimethyl sulfoxide (DMSO)+ethanol or chloroform+methanol at temperatures from 298.15K to 348.15K over wide composition ranges including near critical points. Four pseudo-binary systems of carbon dioxide plus mixed solvents with constant molar ratios of DMSO/ethanol=3/7, 5/5, 7/3, and chloroform/methanol=1/2, were studied in this work. The critical conditions at each investigated temperature were estimated from the experimental isothermal phase boundaries by interpolation. The Peng–Robinson equation of state with the two-parameter van der Waals mixing rules was applied to calculate the phase boundaries. The experimental values were compared with the predicted results from the Peng–Robinson equation using the binary interaction parameters determined from the vapor–liquid equilibrium data of the constituent binaries. The agreement is reasonably well for carbon dioxide+chloroform+methanol, but obvious overestimations are found near the critical regions of carbon dioxide+DMSO+ethanol, especially at higher temperatures.

Lignin-Based Carbon/CePO4 Nanocomposites: Solvothermal Fabrication, Characterization, Thermal Stability, and Luminescence

This work explored the synthesis of carbon-based luminescent materials using cheap, natural resources. Lignin-based carbon/CePO4 nanocomposites were successfully synthesized using previously extracted lignin solution and CePO4, or NaH2PO4•2H2O and Ce(NO3)3•6H2O by the solvothermal method at 200 °C for 24 h, respectively. The lignin solution was previously prepared by the extraction of wood powder in a mixed solvent of dimethyl sulfoxide (DMSO)/lithium chloride (LiCl). All of the obtained lignin-based carbon/CePO4 nanocomposites were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectra (EDS), Fourier transform infrared spectrometry (FT-IR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and photoluminescence (PL). SEM micrographs showed that the CePO4 concentration had an influence on the size, microstructure, and morphology of the carbon/ CePO4 nanocomposites. The experimental results indicated that the obtained lignin-based carbon/CePO4 nanocomposites had excellent PL properties.

Synthesis of well-defined chitosan-based tricomponent copolymers for constructing multifunctional delivery systems

Chitosan-based tricomponent copolymers, chitosan-g-poly(e-caprolactone)-(g-poly(oligo(ethylene glycol) methacrylate)) (CS-PCL-POEGMA, CPP), are synthesized as multifunctional nanocarriers for antitumor therapy. 2-Bromoisobutyric acid and PCL are first site-specifically conjugated onto the hydroxy groups of chitosan backbone through conventional coupling chemistry to give CS-PCL-Br using sodium dodecyl sulfate–chitosan complex as an organosoluble intermediate. CPP-PCL-Br is further used for initiating the single electron transfer-living radical polymerization of OEGMA in the mixed solvent of dimethyl sulfoxide and lactic acid, yielding CPP. One-pot reaction of CPP with a small amount of NaN3 under the catalysis of Cu(I)Br/tris-(2-dimethylaminoethyl)amine converts the bromo ends of POEGMA grafts to azide functionality, which is used for conjugation of folic acid targeting moiety via azide–alkyne click reactions. The resultant tricomponent copolymers can assemble into spherical micelles with the capacity of coincorporating indocyanine green and Doxorubicin through electrostatic and hydrophobic interactions, respectively. The dual-agent-loaded micelles display a combined effect for combating HepG2 cells when irradiated with near-infrared laser. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Synthesis of H‐shaped A3BA3 copolymer by methyl‐2‐nitrosopropane induced single electron transfer nitroxide radical coupling

AbstractAmphiphilic H‐shaped [poly(ethylene oxide)]3‐polystyrene‐[poly(ethylene oxide)]3(PEO3‐PS‐PEO3) copolymer was synthesized by 2‐methyl‐2‐nitrosopropane (MNP) induced single electron transfer nitroxide radical coupling (SETNRC) using PEO3‐(PS‐Br) as a single precursor. First, the A3B star‐shaped precursor PEO3‐(PS‐Br) was synthesized by atom transfer radical polymerization (ATRP) using three‐arm star‐shaped PEO3‐Br as macro‐initiator. Then, in the presence of Cu(I)Br/Me6TREN, the bromide group at PS end was sequentially transferred into carbon‐centered radical by single electron transfer and then nitroxide radical by reacting with MNP in mixed solvents of dimethyl sulfoxide (DMSO)/tetrahydrofuran (THF), and in situ generated nitroxide radical could again capture another carbon‐centered radical by fast SETNRC to form target PEO3‐PS‐PEO3 copolymer. The MNP induced SETNRC could reach to a high efficiency of 90% within 60 min. After the product PEO3‐PS‐PEO3 was cleaved by ascorbic acid, the SEC results showed that there was about 30% fraction of product formed by single electron transfer radical coupling (SETRC) between carbon‐centered radicals. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Gelation-Induced Phase Separation of Poly(vinyl alcohol) in Mixed Solvents of Dimethyl Sulfoxide and Water

Time-resolved light-scattering measurements have been performed on poly(vinyl alcohol) (PVA) in mixed solvents of dimethyl sulfoxide (DMSO) and water with various mixing ratios after quenching from...

Phase behavior and spherical hollow particle formation by dipeptide-based two-headed amphiphiles in a mixed solvent of dimethyl sulfoxide and water

Dipeptide-based two-headed amphiphiles ([(Val) l (Val) l ] 2C 10) in aqueous media transform from rod-like micelles to fibrous structures via vesicle-like intermediates on exposure to acid vapor. A similar phase behavior is present when the molecule is dissolved in DMSO followed by the addition of water (a poor solvent). On the basis of SLS, FT-IR, and FE-SEM measurements, spherical colloids are formed at a small DMSO content (20%) and fibrous structures are formed at a moderate DMSO content (40–60%). This phase behavior is influenced by the chirality of the amphiphiles. A mixed system composed of [(Val) l (Val) l ] 2C 10 and [(Val) d (Val) d ] 2C 10, and a system of [(Val) l (Val) d ] 2C 10 immediately form crystals without formation of spherical colloids or fibrous structures. By optimizing the mixing ratio of the solvents and concentration of the solute, stable micrometer-sized hollow spheres composed of [(Val) l (Val) l ] 2C 10 stabilized by non-covalent bonds are easily prepared.

Effects of cononsolvency on gelation of poly(vinyl alcohol) in mixed solvents of dimethyl sulfoxide and water

We studied the rates of gelation and phase separation of poly(vinyl alcohol) (PVA) solutions in mixtures of dimethyl sulfoxide (DMSO) and water at 25 °C and found that both the rates show a maximum at a volume fraction of DMSO φ DMSO=0.60 while gelation was not observed either in pure DMSO or pure water, suggesting that water–DMSO is a cononsolvent system for PVA. On the basis of the data by Cowie [Can J Chem 36 (1961) 2240] we concluded that the 1:2 stable complex between one DMSO molecule and two water molecules is the main cause of this cononsolvency.

NMR Study of the Stoichiometry, Stability, and Ligand Interchange of Silver Ion-Hexathia-18-crown-6 Complex in Binary Dimethyl Sulfoxide Solvent Mixtures at 300 K

Proton NMR was used to study the complexation reaction between silver ion and hexathia-18-crown-6 in a number of binary mixed solvents of dimethyl sulfoxide with acetonitrile and methanol. Formation constants for the resulting 1:1 complexes in different solvent mixtures were determined by computer fitting of the chemical shift-mole ratio data. The influence of solvent composition on the stability of the resulting complex is discussed. The exchange kinetics of Ag+-hexathia-18-crown-6 in 70-30 wt.% dimethyl sulfoxide-acetonitrile and 75-25 wt.% dimethyl sulfoxide-methanol were studied by proton NMR line-shape analysis. In both solvent mixtures, the exchange of thiacrown ether between the free and complexed sites was found to proceed via a dissociative pathway. The exchange rates and the activation parameters Ea, Δ H‡, Δ S‡, and Δ G‡ for the ligand exchange were determined and the influence of solvent properties on these parameters discussed.

Physicochemical analysis of nucleobase-metal interactions.

It is important to know what kinds of chemical bonds are formed between metal ions and nucleic acids. We have studied metal-nucleobase interactions, by using NMR spectroscopy in solution. For the accurate understanding, we tried measurement at low temperature below -30 degrees C. To avoid freezing of the solution, we have extensively searched solution conditions which is suitable for measurements at low temperature, and found several possible conditions. One was the condition which contained H2O and cryoprotectant at low pH for guanosine-5'-monophosphate--Cd(II), system, the other was the mixed solvent of dimethyl sulfoxide and N,N-dimethylformamide for guanosine--Cd(II) system.