Preparation Of Graphene Using Guanidine Hydrochloride As Reducing Agent

Guanidine hydrochloride, which is often used as an intermediate in medicines, pesticides, dyes and other organic compounds, is an important raw material for sulfonamides and folic acid; it can be used as a strong denaturants in the extraction of total RNA from cells, and used for denaturation and complexation of proteins. It can be used as an antistatic agent for synthetic fibers. In addition, it can also be used as a reducing agent to prepare graphene.

Graphene is a two-dimensional crystal composed of carbon atoms with only one layer of atomic thickness. It is an ultra-thin material with high strength and toughness. It has a large breaking strength which is 200 times more than steel. It has 20% stretching range and excellent electrical conductivity.

Due to its unique quantum effect and excellent electrical, thermal and mechanical properties, graphene has broad application in nanoelectronic devices and integrated circuits, flexible electronic devices, ultra-high sensitive sensor devices and other new electronic devices, composite materials, solar cells, super capacitors, hydrogen storage materials, etc.

The Existing Preparation Method

At present, preparation methods of graphene mainly include physical mechanical stripping method, vapor deposition method and chemical method. Mechanical methods include micro-mechanical stripping methods, epitaxial growth methods and heating of SiC. It is difficult to prepare graphene with large area and uniformly thick.

Compared with physical methods, chemical method for preparing graphene has a high yield. It has the advantages of simple preparation method, low cost and large-scale production, and thus becomes a common method for preparing graphene. However, in the reduction of graphene oxide, the selected reducing agents are mainly hydrazine hydrate and its derivatives, NaBH4, p-phenylenediamine, sulfur compounds, etc. Most of the reducing agents are toxic and explosive, which is not conducive to large scale production.

Therefore, it is necessary to develop a simple, efficient, low-cost and environmentally friendly method.

The researchers developed a method for preparing graphene with guanidine hydrochloride (CAS 50-01-1) as a reducing agent [1]:

(1) Dispersing graphene oxide in water, treating with a cell disrupter for 20~90min and then continuing ultrasonic for 10~60min to obtain a uniformly dispersed graphene oxide with a concentration of 0.1~10mg/mL;

(2) Adding soluble polymer (one of polyvinylpyrrolidone, polyacrylamide, polyvinyl alcohol, polyethylene glycol, hydroxymethyl cellulose, polyacrylic acid) to the graphene oxide dispersion, ultrasonic dispersion 5~30min, a mixed solution of polymer and graphene oxide is obtained, and the mass concentration of the soluble polymer in the mixed solution is 0.01~0.1 mg/mL;

(3) Adding guanidine hydrochloride to the above mixed solution, the mass ratio of guanidine hydrochloride to graphene oxide is 10:1~100:1, and adding alkaline solution (10%~28% ammonium hydroxide, 0.1~5mol/L NaOH solution, 0.1~5mol/L KOH solution) to adjust the pH to 8~12, stir in the oil bath (60~100°C), the reaction time is 1~5h. The water-soluble graphene is obtained by centrifuging and washing.

The preparation method has the advantages of simple preparation process, low equipment requirement, and easy preparation of graphene in large quantities; the presence of the soluble high molecular polymer greatly improves the water solubility of the graphene, and is also beneficial to the further preparation of the graphene film. Guanidine hydrochloride (Guanidinium chloride) can be used as a reducing agent to prepare graphene which can be stably dispersed in an aqueous solution, and the prepared graphene can be used for constructing sensor and electrical device.

Reference

[1] Ma Qi, Song Jinping, Guo Yong, et al. A method for preparing graphene with guanidine hydrochloride as a reducing agent. CN104261393B, 29 June 2016.

Edited by Suzhou Yacoo Science Co., Ltd.

HOW TO TEST OUR HCG 5K IU:

1. dilute Our hcg with 50ml water;
2. Using an HCG-sensitive pregnancy test stick to test, if it is good it will show a positive.

Attention: 
Why must dilute hcg with 50ml water?. Because the pregnancy test stick can not work in  high concentrations of hcg liquid.

We heard HCG-sensitive pregnancy test sticks will show positive by testing the liquid hcg at only put 1mL-diluted bac water. That means HCG concentration is very low. Some HCG on the market is definetely below 5kiu but sell at 5Kiu.
We will shut up when some clients told me how they purchase at much lower prices. We are confident on our price and quality. Our product is competitive compared to most of other suppliers without sacrificing anything on quality.

custompeptidestech.com store is a professional modern High-tech enterprises engaged in HGH and peptide product synthesis research and development, production and sales. more details welcome to contact us.

Ipamorelin--Safest Bodybuilding Peptides

Function of Ipamorelin is similar to GHRP-6 in the way of increasing ghrelin and gastricmotility, and targeting a selective GH pulse. Differ from GHRP-2 and GHRP-6, Ipamorelin cause no hunger side effect, which makes it a versatile peptide for before-bed time dosing.
There is almost no direct impact on cortisol or prolactin production was shown when we're at high dose Ipamorelin. In this case, users can dose higher and with greater frequency without having to be worried about cortisol and acetylcholine blood plasma levels being elevated.
In short, it may be the mildest GHRP, but it is not the weakest. As a GHRP, it has shown to be one of longest lasting, and at higher doses, the most potent. Ipamorelin’s function is a slow building one that is much more like the body’s natural growth hormone (GH) release. This makes it the healthiest choice.


Sides Effects

Among the GHRP family, although Ipamorelin is the mildest and safest peptides, it still comes with side effects. Most users will find the common side effect of a head rush-like feeling and slight headaches. It is suggested that users start supplementation at a lower dose and work their way up. In addition, it is best to inject Ipamorelin 30-45 minutes before working out so that the user is getting the double benefit of both growth hormones working together to maximize results.


Dosage and Usage

Ipamorelin is also comes as a freeze dried powder like other peptides, which is very fragile. It's better to be stored in the refrigerator or at room temperature before reconstituting. Once reconstituted with bacteriostatic water, the vials must be stored in a cool dry place like your refrigerator. Insulin syringes are the best way to administer it, usually via subcutaneous injection.
Using Ipamorelin with a GHRH like CJC w/out DAC will give the users the biggest increase in GH and IGF-1 as GHRP’s and GHRH’s work together synergetically. The average dosing for Ipamorelin is 200-300mcg two to three times daily.

For the preparation of Coatings？The role of TRIS you may not know!

As we all know, Tris(Hydroxymethyl)Aminomethane (TRIS) is not only widely used as a buffer for biological and chemical experiments, but also as solvent for nucleic acids and proteins, intermediates of surfactants, pesticide and drugs. But today, we will introduce the application of TRIS you may not know——For the preparation of Coatings.

TRIS (THAM) plays four main roles in the preparation of the coating: pH regulator, crosslinking accelerators, polyester coating materials and phase change cores.

1. pH Regulator

The effective buffering range of TRIS buffer is pH 7.0~9.2. Yuan et al. [1] invented a non-yellowing polyester coating with best pH value of 7.5~8.5 in the preparation. Researchers used TRIS buffer to adjust the pH value. The prepared product had good adhesion and scratch resistance, and it will not significantly yellowed after high temperature operation or aging.

2. Crosslinking Accelerator

Crosslinking accelerators can act as bridging molecules between linear molecules, so that multiple linear molecules are bonded to each other to form a network structure. Polyhydric alcohols are often used as external crosslinks in the preparation of coatings. Zhang Jianwei et al. [2] invented a silane modified polyurethane glass coating with TRIS as a cross-linking promoter. Which can be operated in the air at room temperature for 40min without obvious thickening phenomenon.

3. Polyester Coating Materials

Polyhydric alcohols, polyacids, catalysts and antioxidants can be used as a coating composition. Deng Mujian et al. [3] used TRIS as the polyhydric alcohols to react with the polybasic acid or anhydride terephthalic acid or isophthalic acid, to obtain an outdoor dry blending powder coating polyester resin.

4. Phase Transition Core

When the temperature reaches the phase transition temperature, the structure of the polyol phase transition material will change from the layered body-centered structure to the isotropic facial-centered structure, and the hydrogen bonds between the layers are broken, molecules change from crystalline to amorphous, and release bond energy. It has the advantage of large enthalpy of phase change, stable performance, long service life. Gao Hongyi et al. [4] used the polyol characteristics of TRIS as a phase change core to prepare an airgel based phase transition coating.

TRIS (CAS 77-86-1) is not only an important biological buffer, but also an important material for organic synthesis. Although the application in the field of coatings is not very extensive, but with the development of science and technology, we believe that TRIS will get more applications in this area in the future.

References

[1] San C. Yuan, Mitchell S. Chinn. Non-yellowing polyester coating composition. US 7,087,672 B2, August 8, 2006.

[2] Zhang Jianwei, Du Houjun, Wang Yudong, et al. Silane modified polyurethane glass primer and preparation method. CN 102516921 B, 2013, 10, 02.

[3] Deng Mujian, Zhang Liangfu, Cao Yongyi, and so on. Preparation of polyester resin for outdoor dry blending powder coating. CN 102719180, 2012, 10, 10.

[4] Gao Hongyi, Feng Yanhui, Zhou Xiaofei. A preparation method of air-gel-based thermal phase transition coating. CN 105199472, 2015, 12, 30.

Edited by Suzhou Yacoo Science Co., Ltd.

EDOT(126213-50-1) as electrolyte additive for lithium ion battery

The safety of lithium ion battery is one obstacle to limit its large-scale application in automobile. Some researches show that decomposition of electrolyte on cathode under high potential is one reason leading to the thermal runaway or even the combustion of electrolyte. In order to solve the above problem, one way is to form a thin film on cathode surface to prevent the decomposition of electrolyte on it. Researchers have found that 3, 4-ethylene dioxythiophene (EDOT) can be used as electrolyte additive to improve the safety of the battery. And the addition of EDOT has no effect on electrochemical performance of lithium ion battery. Some details of the experiment are described as follows.

In the experiment, LiCoO₂ was used as cathode and EDOT was added into the standard electrolyte. Oxidation potential of EDOT was measured by cyclic voltammetry which oxidation peak occurred at 3.95V, which is situated at the range of charge voltage of LiCoO₂. So EDOT can be oxidized to form polymerization film (PEDOT) on cathode surface in the first charge-discharge cycle. And TEM experiment also verifies this. The polymerization film on cathode surface suppresses the decomposition of electrolyte to improve the lithium ion battery safety.

The thermal stability of LiCoO₂ cathode after delithiation in the electrolyte with EDOT or without is detected by DSC. The experiment results show that PEDOT-modified cathode has a 26% exothermic reduction. And this demonstrates the heat generation due to electrolyte decomposition is reduced to a certain extent. The cyclic performance of the full cell shows that the capacity retention is improved for the electrolyte with addition of EDOT.

In a word, EDOT polymer as electrolyte additive can improve the safety of lithium ion battery. And it has no effect on electrochemical performance of lithium ion battery.

Edited by Suzhou Yacoo Science Co., Ltd.

Bicine running buffer providing enhanced resolution and representation of membrane proteins

SDS-PAGE method is used to separate protein prior to analysis by MS. And running buffers, such as glycine- or Tricine-based, will have an effect on the protein separation process. Tricine-based running buffer systems have been successfully applied in the separation of various types of proteins.

Although Tricine-dSDS-PAGE is a powerful tool in membrane protein separation, williams et al. (DOI:10.1002/elps.200500730) also explored other buffer systems in conjunction with the dSDS-PAGE approach and describe an orthogonal Bicine-dSDS-PAGE method for the analysis of membrane proteins from the anaerobic bacterium, Clostridium thermocellum. And they compared glycine-, Tricine-, and Bicine-dSDS-PAGE systems.

Firstly, thermocellum cell cultures were grown at 55 °C and harvested. And glycine-, Tricine-, and Bicine-dSDS-PAGE were used to separate the proteins in the first dimension using Laemmli protocol, then further separation in the second dimension. Due to SDS-PAGE gels and running buffers are normally operated in the 6.6-8.8 pH range, which makes Bicine-(pH range of 7.6-9.0) and Tricine-based (pH range of 7.4-8.8) buffer systems somewhat more suitable. And according to experimental results of the first dimension, the optimized parameters for gel separation in Bicine- and Tricine-dSDS-PAGE were obtained. Based on the optimized parameters obtained, large-format experiments were performed to further improve protein representation and increase protein loading capacity of the gel.

In the work of Williams et al., they found using electrophoretic buffer systems other than the traditional Laemmli approach increase resolution and representation of membrane proteins. And it was found that Bicine-dSDS-PAGE provided the best separation condition of all.

Edited by Suzhou Yacoo Science Co., Ltd.

Is HEPES suitable for the in vitro testing of inorganic biomaterials in SBF?

Recently, much work has focused on the development of inorganic materials in bone tissue engineering, such as glass and glass scaffolds. These inorganic materials classified as “bioactive” should first pass an in vitro test in simulated body fluid (SBF).In the test, an inert buffer to keep neutral pH is necessary to maintain conditions close to those in blood plasma. According to an international standard (ISO:23317:2014) for the test, Tris(hydroxymethyl)aminomethane is using to maintain neutral pH in SBF.

In 2011, Rohanova et al. found that TRIS buffer used with a highly reactive glass-ceramic scaffold accelerates the dissolution of the glass-ceramic crystalline phase and lead to the formation of hydroxyapatite. It demonstrates that TRIS buffer is not suitable for in vitro testing. So other alternatives must be sought.

Rohanova et al. evaluated whether would HEPES buffer be more suitable for SBF. They studied the interaction of HEPES buffer with the glass-ceramic scaffold (45S5 bioactive glass-based) through comparing SBF with HEPES and demineralized water with HEPES. The tested scaffold was exposed to the media under a static-dynamic arrangement for 15 days. Leachate samples were collected daily for analysis Ca²⁺ ions and Si, (PO₄)^3- ions, and to measure pH. The glass-ceramic scaffold was analyzed by SEM/EDS, XRD, and WD-XRF before and after 0.3,1,3,7,11,15 days of exposure. Their results confirmed the rapid selective dissolution of the glass-ceramic crystalline phase containing Ca²⁺ ions due to the presence of HEPES, hydroxyapatite supersaturation being reached within 24 h in both solutions. These results suggest that HEPES is also not suitable for the in vitro testing of highly reactive inorganic biomaterials (glass, glass-ceramics).

In a word, findings of Rohanova et al. show that TRIS and HEPES buffers are not suitable to maintain the neutral pH for the in vitro testing. Consequently, researcher will work further to test other buffers to find suitable alternatives.

Edited by Suzhou Yacoo Science Co., Ltd.