主题：【转帖】液相系统的定期清洗

转自小木虫，作者：PAborall

原文：（内部资料）
Cleaning the $$lc System for Best Nanoelectrospray Sensitivity
 
This is the cleaning procedure I used for my Nanoflow Proteomics Solution system to achieve the best sensitivity.  The flush times are approximate and were dictated by my schedule more than any absolute requirement. 
 
Note:
I cleaned my system for direct mode analysis and only the column/nanospray needle/MS were not included. 
I cleaned all 4 channels simultaneously.  Even though only 2 channels are needed, but this would be optional. 
How long the system stays clean will probably depend on the samples run, but my system has maintained a low background for almost 2 months. 
Flushing was usually done at 4 uL/min to ensure sufficient backpressure and to aid in cleaning.  When changing solvents, all channels were purged at 2500 uL/min for 2 minutes/channel 
Procedure:
1. Be sure to remove columns and MS from system.
2. Flush B channel with hot water (about 60 deg) for 20 minutes to remove any acetonitrile polymer (optional: more important for older systems)
3. Flush with water at RT for 10 minutes. 
4. Flush with !°cleaning solvent!± which consists of 2:25%:50% 
cyclohexane/acetontirile/isopropanol for 30-60 minutes. 
Note:  this solvent mixture is used only for rinsing / steam cleaning and should not remain in the $$lc system for an extended period of time.  It has been reported that cyclohexane may be harmful to the $$lc pump seals.  Therefore, make sure to remove the solvent mixture from the system after the cleaning procedure is finished. 
5. Flush all channels copiously with water on all channels for 30 minutes.
6. Flush with 20% nitric acid at a low flow (< 1 uL/min) for several hours.
7. Flush copiously with water (several hours). 
Note: Use a beaker for the water and be sure to change the water and the beaker several times in the first hour as there will be lots of nitric acid in the spargers. 
8. Flush with 200 mM ammonium formate until the pH is close to neutral
and then flush again with water. 
9.        Restore the normal solvents and stabilize the system. 
译文：
为使钠喷雾具备高灵敏度而进行的液相系统清洗
下面是我为获得最高的灵敏度而对钠流蛋白质组学溶液系统的清洗步骤。 清洗的频率取决于已定的计划，而不是到了非清洗不可得的时候在洗
注意：
A  清洗的系统是单纯流路系统，需将色谱柱、钠升电喷雾、质谱隔离
B  同时清洗4个通道，即使仅有2个通道在使用，这是可以随意选择的
C  清洗的时间取决于所跑的样品，但我的系统已约2个月保持在低背压
D  冲洗时，流速一般设在4ul/min以保证足够的背压和帮助清洗。当更换溶剂时，所有通道都要用2500ul/min保持2分钟以清除原溶剂
步骤
1、确保色谱柱/MS从系统中移走
2、用热水(60度) 冲洗B通道20min ,以清除任何乙腈聚合物（建议：较老的系统很重要）
3、用水冲洗RT10分钟
4、用清洗溶剂（（环己烷；乙腈；异丙醇）-25:25:50）冲洗30—60分钟 
注意：此种清洗溶剂仅用于清水/蒸汽清洗，不应长时间滞留在液相系统里。据报道，环己烷对液相泵的密封系统有损害。因此，清洗完成后确保将清洗溶剂完全清除
5、用水充分地冲洗所有通道30分钟
6、用20%的硝酸低流速（＜1ul/min ）地冲洗数小时
7、充分用水冲洗数小时
注意：在第一个小时里， 用一大烧杯装水，并确保更换几次烧杯和水，因为有大量的硝酸在装置中
8、用200 mM甲酸铵清洗，直至pH接近中性，然后再用水冲洗
9、换用正常的溶剂，平衡系统