仪器的状况:
1) 正相电压。之前使用正相电压的时候,90%都会出现“current leakage”。今天 30 cm毛细管用20 mM phosphate buffer 25 psi 冲洗了 5min后,用Direct Control 来测试仪器,结果正相电压在30kV 的情况下 电流从67 uA 一分钟内上升到了 150 uA, 手动停止了高压。(电流持续夸张上升
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)。
2)反相电压。相同条件下,Direct Control测试反相电压,电流稳定在67uA,虽然偶尔会出现"Current leakage", 不过还能用:)。
已经和Beckman的 specialist 讨论很久关于仪器Current leakage的问题,到最后还是得 on-site service,不过这个on site service 得 $7,000左右,老板也没有计划在CE上面投入那么多钱(组里做HPLC的多)
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。
虽然没有寄予太多希望能够解决问题,不过还是想看看大家的意见
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。
1. The capillary is broken at the window.2. One of the electrode is loose.3. Conditioning of the capillary before applying voltage (buffer should be conditioning with the separation buffer before applying voltage).4. Buffer composition - also make sure the same separation buffer is on the inlet and outlet side.5. Bubbles in the buffer.6. Make sure the caps are not wet (don’t overfill the buffer vials), the interface block and injection levers are clean and free of buffer/gel.7. Problem with the interface block and/or high voltage power supply (only a qualified engineer would be able to assess this).
目前,1~6 都可以排除,希望可以得到更多关于高压源和横梁的建议。