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清除收集极积垢，拆洗FID时，常把喷嘴拆断造成了不可挽回的损失。依据FID工作原理，收集极对地为高阻，一般都在107欧姆以上，所以收集极的一般污染或收集极和静电计连接不良，除非在限制灵敏度操作外不会造成严重的噪声。所以当操作FID遇到尖峰噪声（基线毛刺）不提倡首先拆洗FID检测器，而应先寻找其它引起噪声的原因如： 1.气流比是否合适； 2.汽化室严重污染； 3.柱流失严重（老化不够）； 4.静电放 ...

硅烷化试剂在GC分析中用途很大。许多被认为是不挥发性的或在200～300℃热不稳定的羟基或氨基化合物经硅烷化后成功地进行了色谱分析。 硅烷化作用是指将硅烷基引入到分子中，一般是取代活性氢。活性氢被硅烷基取代后降低了化合物的极性，减少了氢键束缚。因此所形成的硅烷化衍生物更容易挥发。同时，由于含活性氢的反应位点数目减少，化合物的稳定性也得以加强。硅烷化化合物极性减弱，被测能力增强，热稳定性提高。 正是 ...

色谱柱的正确安装才能保证发挥其最佳的性能和延长使用寿命。 正确的安装请参考以下步骤： 步骤1、检查气体过滤器、载气、进样垫和衬管等检查气体过滤器和进样垫，保证辅助气和检测器的用气畅通有效。如果以前做过较脏样品或活性较高的化合物，需要将进样口的衬管清洗或更换。 步骤2、将螺母和密封垫装在色谱柱上，并将色谱柱两端要小心切平。 步骤3、将色谱柱连接于进样口上色谱柱在进样口中插入深度根据所使用的GC仪器不 ...

在我们进行液相色谱分析时，有时会遇到这样一个问题：系统的流路中存在气泡。 由于气泡的存在，会造成色谱图上出现尖锐的噪声峰，严重时会造成分析灵敏度下降；气泡变大进入流路或色谱柱时会使流动相的流速变慢或不稳定，使基线起伏。 造成上述现象的主要原因有三条：一是流动相溶液中往往因溶解有氧气或混入了空气而形成气泡；二是系统开始工作时未能将流路中的空气驱赶干净；三是在注入样品时不注意混入了空气。 为了避免这类 ...

《常见色谱故障与异常》下载 点击这里下载 ...

“质谱分析三离子原则”只是对质谱图分析结果解析需遵循的规则的另一种表述方式而已。具体来讲，解质谱图时需遵循以下规则：分子离子峰、重要碎片离子峰（重要低质量碎片离子、特征离子）、亚稳离子（如果有的话，找到母、子离子对，获得母离子与子碎片离子的关系，特别时由分子离子产生的亚稳离子更应引起重视，这对推测结构很重要。）应得到合理的解释，或至少其中大部分峰能得到合理解释，找到其归属。 ...

This protocol is adapted from protocols by Nicole Bechtold (Bechtold et al. 1993) Andrew Bent (Bent et al. 1994) and Takashi Araki. No claims are made that any of the steps are necessary or ideal; the ...

day 1 1. Start 75 mL overnight cultures of agro (strain GV3101 C58C1 Rifr pMP90 Gmr Koncz & Schell) in YEP in 250 mL baffle flasks. 2. Grow at 28 °C shaking. 3. Prepare: ~ 3.5 L sterile H2 ...

(Brief version for those who are familiar with the method) Steve Clough and Andrew Bent University of Illinois at Urbana-Champaign. Our present protocol (Clough and Bent 1998; modified from Bechtold ...

Based on Krapp at al (1993) Plant Journal 3:817 with modifications. Comments or Questions? Send to me at: chunming.liu@wur.nl ------------------------------------------------------------------------ ...

This method is derived from a procedure developed by Toby Bradshaw and the Poplar Molecular Genetics Cooperative. We have tested the procedure with a variety of Populus species as well as tobacco and ...

Procedure Preheat Extraction Buffer at 60°C. Weigh 100 mg of fresh leaf tissue and grind it to powder in Liquid Nitrogen in a chilled mortar and pestle. Add 0.5 ml of TE buffer to the tube. Ce ...

Solutions: Extraction buffer: 200 mM Tris-HCl pH 7.5 250 mM NaCl 25 mM EDTA 0.5% SDS Arial He ...

A protocol / method / schedule /procedure for extraction / isolation of both DNA and RNA from the same material typically plant leaf / leaves (See also DNA Isolation protocol) 1) Take one medium siz ...

CTAB TECHNIQUE / Method / Schedule / Protocol FOR DNA ISOLATION / DNA EXTRACTION FROM PLANT LEAF / LEAVES SAMPLES (see also DNA RNA double isolation procedure if both DNA and RNA are needed) Reagent ...

1.collect piece of tissue (e.g. pieces of a leaf or flower) in Eppendorf tube containing 40 ml 0.25 N NaOH 2.put in boiling H2O for 30 sec (optimum may need to be determined for each type of tissue f ...

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1.weed out the plant pot leave only about 3 to 8 tall and vigorous plants (in a regular 5 cm pot) 2.on an individual inflorescence cut off all the opened flowers (older than stage 13) the youngest de ...

We use Dimilin G (4% diflubenzuron) from Maag AG to fight the small dipteran black flies (Trauermücken). It is a granular substance and sprinkled onto the soil when the plants show the first few ...

sterilisation of seeds: rinse with 70% EtOH for 30 sec put in 1% bleach (sodium hypochlorite supplemented by a few drops of Tween-20) for 5 min wash 2-4x with sterile H2O for 1 min plating and gro ...