Team:Nanjing-China/HP/Gold Integrated
On September 15th, four members of our Nanjing-China team went to the Blue Star ADISSEO Company which was located in the chemical park of Liuhe District in Nanjing. We went there with the purpose of carrying out on-site research on harmful gas safety. Three workers of the company's security department were quite hospitable during the whole reception. As we could see, the company's security measures were very strict, visitors were required to register, change into the labor security clothing before visiting the plant, wear helmets and goggles and turn off the phone and all other electronic equipment.
Firstly, we went to the office area for interview. The main business of Blue Star ADISSEO covers the development and production of methionine. The process involves a large quantity of hydrogen sulfide so gas leakage detection is of great importance. The whole plant has a total of more than 100 fixed hydrogen sulfide detectors, each of which can detect a radius of 5 meters. The maximum allowable concentration of hydrogen sulfide in the air is 10 mg / m3. When the concentration reaches 3 ppm (about 4.56 mg / m3), the fixed instrument will issue an alarm while it will issue a high alarm with the concentration of 6 ppm.
The company's security department conducts an overall inspection of the 300 gas detectors, which usually takes about two weeks. Every year, the company has to accept the national compulsory security checks. Once the company meets the qualifications, it will obtain the relevant certificates.
The detector is made up of two parts, the main body with a display panel and the sensor probe. The former one is of 6-7 thousand Yuan while the latter is of 3-4 thousand Yuan. As the hydrogen sulfide and the electrolyte inside the sensor has an irreversible chemical reaction, it needs a regular replacement. Its life can reach up to 3 years if no special circumstances occur. But the frequency of replacement might be high where the leakage of hydrogen sulfide happens more easily. In addition, the intelligent property of the instrument ensures that it will automatically issue an alarm to remind the staff of replacing the probe when the sensor’s life is less than 10%.
In addition to the hydrogen sulfide detector around the device, whenever a leak or a suspected leakage occurs, the relevant technical staff need to wear a respirator breathing mask and hold a portable detector into the field to find the leak point. At the moment of interview, there were several portable detectors charigng in the office. One of the workers volunteered to demonstrate the operation for us. (See video)
Because the sensor is affected by temperature, air pressure, gas flow rate and other factors, sudden change of the weather (such as summer thunderstorms) may cause zero drift resulting in false positives. At that point, the staff will decide whether to evacuate based on the scene. If the alarm is true, workers will quickly evacuate all the people to the upper area and then involve the security sector personnel in. If the leakage is serious, the device will automatically cut off all the reactions so that the root source of the generation of hydrogen sulfide is cut off. If the device is due to the aging of the tiny holes, the company will immediately invite the department of maintenance to conduct the emergency plugging. And they will replace the whole pipe during the shutdown inpection period annually.
Under the guidance of the workers, we participated a simple safety training. We put on a full set of labor security clothing, wore reflective vests, helmets and goggles and visited the control room and the device around the fixed sensor. It was really hot under the sun, we were all sweaty wearing the clothes. Once thinking about the factory workers who wear the clothes every day, we were really touched by their dedication to their job.
On September 27, three members of team Nanjing-China went to interview professor Zhang yan in School of chemistry and chemical engineering in Nanjing University , who focus on the design and construction of molecular probes for molecular imaging.
The students who were responsible for the formaldehyde probe experiment first expressed the confusion about the linear relationship between the fluorescence intensity and the concentration of formaldehyde aqueous solution. Prof Zhang mentioned the measurement of target protein and formaldehyde molecules binding constants, and reminded us to make it clear the relationship between extracellular formaldehyde concentration and intercellular formaldehyde concentration , so as to know how much the effective combination of quantitative detection of formaldehyde molecule and protein.
Prof Zhang noted that the experimental environment was our solution, but our goal was to detect gas content in the air, so she reminded us thinking how to achieve gas enrichment to the solution. She said that chemical reactions were often used to convert the detected substance into another one, but it was not possible for us to specifically target formaldehyde, hydrogen sulfide, and hydrogen. She then talked about another chemical method using a model substrate so that in the bacterial culture environment with formaldehyde, we could achieve high concentration of formaldehyde in the cell microenvironment.
Prof Zhang encouraged us not to focus too much on the whole cell probe, but to think the concept of smart cell. She believed that even at this stage of the physical and chemical probe occupying a strong market, we could still prove that the whole cell sensing system was extremely advantageous.
Next, we consulted Prof Zhang for the safety of experimental operations. She reminded us that the operation must be completed in the volatile solution in the fume hood; for the organic solution of different concentration, we had to concern about cell tolerance and find the maximum operating concentration from database to protect the safety of personnel.
Prof Zhang said we had to know if the target gas metabolism pathway of the cell itself interferes with our experiments. She agreed that hydrogen sulfide and formaldehyde were important signaling molecules in organisms. If the target gas in cells is of a high affinity, it is bound to have a certain impact on the results of our experiment.
Finally, we compared the similarities and differences of small chemical molecules in traditional probe and Prof Zhang recognized the innovations and challenges of our project and wished the experiments to achieve good results.
Greatly inspired from our trip to AddiseO and our interview with professor Yan Zhang, we have designed and made a little film about the bio-safety measures in our lab.
Besides bacteria, fluorescent dyes and UV light, we deal with formaldehyde and hydrogen every day, which poses great threat to our safety. Therefore, it is of great importance to conduct all the experiments under certain bio-safety norms which cater our specific needs.
There are altogether four parts in our film, including explanations of operations in the super clean bench, in the fume chamber (formaldehyde-related), in the gas chamber(hydrogen-related) as well as under the UV light.
In this film, we try to not only promote the bio-safety measures in our lab but also encourage more teams to engage in this huge cause and find better solutions.
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Nanjing, Jiangsu Province
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