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今日新聞                 日期：2022/9/15

 

在氣相色譜儀分析中，進(jìn)樣是定量分析誤差的主要來(lái)源之一。因?yàn)檫M(jìn)樣系統(tǒng)的原理、結(jié)構(gòu)、使用材料、進(jìn)樣時(shí)的溫度、進(jìn)樣量、進(jìn)樣快慢、進(jìn)樣用的工具等都會(huì)對(duì)氣相色譜分析的定性定量的重復(fù)性和準(zhǔn)確性產(chǎn)生直接影響。在實(shí)際分析中由于樣品的氣、液、固、狀態(tài)不同，分析目的不同，要求不同，用于氣相色譜儀的進(jìn)樣系統(tǒng)種類繁多，如：常壓氣體樣品就有六通閥氣體進(jìn)樣或注射針筒進(jìn)樣兩種。 常壓氣體樣品采用醫(yī)用注射器（1毫升~5毫升）通過(guò)注射隔墊注射進(jìn)樣，簡(jiǎn)單、靈活，但缺點(diǎn)時(shí)有樣品反沖和滲漏，定量誤差大，重復(fù)性一般在2.5%以上。這是因?yàn)橹皦焊哂诃h(huán)境大氣壓力，樣品氣會(huì)沿注射管內(nèi)壁滲漏造成的。這時(shí)雖然可以通過(guò)在管內(nèi)壁上涂一層高溫真空硅脂提高氣密性來(lái)彌補(bǔ)，但又會(huì)出現(xiàn)硅脂對(duì)有機(jī)物的吸附作用，定量誤差仍然很大。若用六通閥定體積進(jìn)樣，不但操作方便、迅速切結(jié)果也較準(zhǔn)確。只要操作合理又掌握一定的技巧，重現(xiàn)性可小于0.5%。即使環(huán)境溫度、壓力變化或不同校正起來(lái)也很容易方便。另外，六通閥還可以直接用于高壓氣體進(jìn)樣。

英文翻譯：

In gas chromatograph analysis, injection is one of the main sources of quantitative analysis error. Because the principle of the injection system, structure, the use of materials, injection temperature, injection volume, injection speed, injection with T tools will have a direct impact on the qualitative and quantitative repeatability and accuracy of gas chromatography analysis.In the actual analysis,due to the different gas, liquid,solid and state of the sample,different analysis purposes and requirements,there are a variety of injection systems used in the gas chromatograph, such as:atmospheric pressure gas samples have six valve gas injection or injection needle injection of two kinds. The medical syringe(1ml~5ml)is used to inject the atmospheric gas samples through the injection pad ,which is simple and flexible,but has the disadvantage of sample backlash and leakage, large quantitative error, and the repeatability is generally more than 2.5%.This is because the pre column pressure is higher than the ambient atmospheric pressure, and the sample gas will leak along the inner wall of the injection tube.At this time,although it can be made up by coating a layer of high-temperature vacuum silicone grease on the tube wall to improve the air tightness, the adsorption effect of silicone grease on organic matter will appear,ａnd the quantitative error is still large.If six-way valve injection volume,not only convenient operation,rapid cutting results are more accurate.As long as the operation is reasonable and certain skills are mastered,the reproducibility can be less than 0.5%.Even if the ambient temperature,pressure changes or different correction is easy and convenient .In addition, the six pass can also be directly used for high pressure gas injection.