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【求助】顶空气象残留问题

气相色谱(GC)

  • 我用的是安捷伦7694E-7890A顶空气象,老化和乙醇进样清洗后,还是有残留,该怎么办????

    怎么排除那些顽固的残留!?????
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  • guohua

    第1楼2009/04/16

    记得有一个清洗残留的程序,瓶中加水,平衡温度120度,延长蒸汽进入Loop时间,可以清洗流路,仪器手册中应该有,以手册为准。

    另是什么残留啊?

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  • hyhy303

    第2楼2009/04/17

    检测的组分是挥发性有机化合物,主要是苯系物,醇类,酯类,酮类。我想可能是这些残留,FID不是最怕水的吗?
    好像不能用水洗,你说的是不是扯下柱子再洗啊??

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  • guohua

    第3楼2009/04/17

    呵呵,不是用水洗,是用水蒸气冲洗Loop流路,下面是7694手册里的说明:

    Steam Cleaning the Pneumatic System


    Steam cleaning removes components of the sample that could stick to the
    surfaces of the flowpaths and valves. For example, polar compounds tend to
    stick to these surfaces and may appear as carryover when running solvent or
    air blanks after samples. For safety reasons, Agilent only recommends water as
    the cleaning agent.
    The success of the cleaning procedure will vary depending on your application.
    Check the results to assess the value of steam cleaning.
    Disconnect the transfer line from the gas chromatograph or 5973 MSD.
    Injecting water vapor into the gc will damage the column. Injecting water
    vapor directly into the MSD may shorten the life of analyzer components. You
    may have to cool down the gc or vent the MSD before disconnecting the
    transfer line.
    Use vial septa that can handle the temperature and pressure associated with
    this procedure. Agilent recommends septa part number 9301-0719, tan PTFE/
    white silicone septa, –60°C to 125°C. These are the septa provided in the part
    number 5182-0840 preassembled 20-ml vial kits.

    1. Prepare the gc or MSD.
    2. Prepare 23 vials: 20 vials with 1 ml of distilled water and 3 air blanks.
    3. Disconnect the transfer line. Set the carrier flow so that it is less than
    100 ml/min.
    4. Enter the following parameters on the headspace sampler keypad:
    Function Parameter Settings
    Zone Temps 125°C, 140°C, 150°C
    Event Times (minutes) 2.5, 15.0, 0.0, 0.2, 0.2, 1
    Vial 1 1, 23, 0 (off)

    5. Start. It takes about 70 minutes to complete.

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  • tfs321

    第4楼2009/04/28

    我用的是G1888顶空进样,残留是不太出现的,如果是乙醇的话,进两针空白看看,也许是色谱柱的残留。如果是色谱柱的残留。用程序升温来排除残留。

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