Instructions for purchasing a gas chromatograph

Taking the gas chromatograph used in the laboratory as an example, there are more than a hundred types and models of domestically produced products. The technical performance, functional characteristics, price, and operating characteristics of different products vary greatly. In addition, the samples to be analyzed are strange, and the analysis purposes and requirements are different. For those chromatographic users who have not worked for a long time and have little experience, they should be able to purchase a gas chromatograph according to their own needs. For example, there are no fewer than a hundred types and models of domestically produced products, and the technical performance, functional characteristics, price, and operating characteristics of different products vary greatly. In addition, the analyzed samples are strange and the analysis purposes and requirements are different. For those chromatographic users who do not work for a long time and have little experience, they should be able to purchase an instrument with an appropriate performance/price ratio according to their needs. An easy task. In order to help you buy a chromatograph quickly, well, and save land, here is how to choose a gas chromatograph. Several considerations are categorized and analyzed for your reference. 1. Situation of the analyzed sample: ⑴ The composition and state of the sample itself, is it gaseous, liquid, solid or mixed, can it be directly analyzed by gas chromatograph? ⑵ Is the measured component thermally unstable, easy to decompose, or easy to catalyze the reaction. Whether changes in time, temperature, pressure, etc. will cause changes in the measured components; ⑶ Whether there are smoke, suspended solids, high Buddha point components and corrosive components in the sample. Consider how the samples are collected and obtained, and how to pre-process the samples; ⑷ u200bu200bIs the source of the samples easy? Allowing the consumption of samples is conducive to the selection of sample injection methods; ⑸ Components that do not need to be analyzed and the approximate concentration range; ⑹ The number of samples to be analyzed per day, and the interval between two analyses; 2. What is the purpose of the analysis? ⑴ Do qualitative analysis: Is the analyzed component known or unknown, is there a standard substance? ⑵Quantitative analysis: in that range-constant (10-1`~10-3); semi-trace (10-3~10-5); trace (10-5~10-7); trace (10-6~ 10-9) or ultra-trace (≤ 10-9) ⑶ Quantitative accuracy and analytical accuracy, if semi-quantitative requirements are much simpler. 3. Positioning of the purchaser: ⑴Scientific research institutes-high requirements; ⑵ Monitoring and analysis center-accurate and reliable; ⑶For first-line on-site analysis-repeated reproduction; 4. The same sample, theoretically There may be a variety of instrument analysis methods, from the performance/price ratio of the instrument, the operating characteristics, and the maintenance service comparison, to list the reasons for choosing a gas chromatograph for analysis. 5. Consult to find out whether there are national standards, industry standards, corporate standards or foreign related reference materials for the analyzed samples. If there are, the standards will give the functions and technical requirements of the instrument that should be used in general occasions. 6. Whether there are analysts who do similar samples around the work unit, if there are any direct help for the selection and the establishment of chromatographic analysis methods in the future; 7 Collect samples and data of various types of gas chromatographs (including accessories), Make basic preparations for the final selection; 8 is the task long-term? Is it short-term? How much investment is determined due to different tasks, and which instrument to choose? Do you want to make long-term plans? 9 What are the current conditions? There are many units for a new analysis task. The existing instruments can be fully qualified for the job after proper modification and re-establishment of analysis methods; if the conditions are met, there is no reason to invest in new instruments and equipment; 10 considering the choice The working efficiency of equipment, operating costs, own manpower (technical level), and financial resources are not easy to choose those so-called high, precise, and cutting-edge products. In short, it is based on practical economy. 11. The chromatographic data processing device is the necessary equipment to finally give the analysis results. It should be purchased according to the specific requirements of the type and format of the information required for the analysis results. You must not ignore the financial resources and choose those with price and excess functions. Chromatography workstation. Some samples have few components and are well separated. Why use a few thousand yuan recorder and chromatographic data processor to complete the work, why spend tens of yuan to buy a computer that is not efficient and time-consuming for data processing? 12. Use occasions and instrument installation location: Although the gas chromatograph is relatively optical instrument in the use occasion, the installation location requirements are not strict, but the following conditions should be paid attention to when operating certain detectors and high-sensitivity work: ⑴Use occasion: temperature, humidity, Atmospheric pressure, vibration, electromagnetic interference, corrosive gas, ventilation, stray light, water source, dust, etc. may affect the operation of the instrument; (2) The installation base of the instrument is stable and anti-vibration, the area size, location, and maintenance are convenient; (3) Air source The supply method, installation operation, purity, etc. can meet the requirements.