Why are HPLC columns shorter than GC columns?
HPLC和GC是分离技术，在化学实验室中获得了强大的立足点。两种技术的基本目的是分离和量化有机混合物的组成部分。
Have you ever wondered whyHPLC列比GC列更短且更宽。在回答这个问题之前，您应该了解长列长度的好处。随着列的长度增加，洗脱化合物和固定相之间的相互作用时间增加，从而提高了柱效率和分辨率。这导致峰值良好。但是，由于柱头压力增加以及分析时间增加，由于实际问题所面临的实际问题，柱长度不能无限期增加。
HPLC columns
HPLC列的尺寸要求取决于分离目标。通常的分析应用需要长度为15 - 25 cms的列，其ID为4.6 mm，而准备柱的直径范围为20 - 50 mm。
GC列
GC列are basically classified as packed columns and capillary columns. Packed columns are generally about 1.5 m or 6ft long and 1/8” or 3.2mm outer diameter.. Capillary columns on the other hand are several meters in length(10-100m). Packed columns are made of glass or stainless steel whereas capillary columns are made of fused silica flexible tubing. Flexible tubing permits accommodation of long length columns as circular coils into the column oven
Now examine the difference in the separation process in the two techniques to arrive at logical answer to the basic question on length differences between GC and HPLC columns..
Nature of mobile phase –the first and foremost reason is nature of carrier fluid termed as mobile phase. HPLC uses a liquid as a carrier of sample through the column whereas in GC a gas stream serves to carry the sample. Liquids have higher viscosity than gases and therefore encounter greater resistance during passage through the column. The longer the column greater will be the resistance to flow of mobile phase therefore HPLC requires shorter column lengths
Sample volatility –the sample injected into the HPLC is a liquid whereas in GC it can be either a liquid or a gas. However, before entering the GC column: liquids get converted to vapours due to high temperature in the injector block. A gas encounters less resistance in the GC column which permits use of longer column lengths.
样品稳定性 -通过HPLC分析的样品通常是热不稳定的，因此在室温下，它们处于HPLC柱中的液相。另一方面，进入GC柱的样品是具有较低分子量和沸点的气体。这样的化合物很容易蒸发，并在通过色谱柱的过程中保持为气体。
柱状长度的进一步降低，特别是在新的UHPLC应用中，导致了加速分析，并提高了灵敏度。分析应用中的未来趋势将限制HPLC列的长度和分析时间从几分钟到几秒钟。
please tell me interview quation and anser hplc &gc
嗨，Sanjeev，
The answers to interview questions can be found in the course material itself.These are only some specimen questions designed specially to encourage you to go through the course thoroughly and increase your inquisitiveness.
真的很好，对于发展自己的分析技能…………..理论上。
Thanks. Nice to know you liked it
它非常有用，我学到了基本概念ANG合格的BPS 17讲师
in analytical chemistry
Thanks Asma for your encouragement.
Dear Sir
我想知道科学世界中HPLC的范围在哪里，并且可以通过这种放大的仪器分析哪种类型的样品（有机和无机）。
Dear Sandeep,
您可以订阅HPLC上的免费课程，该课程将为您提供所需的详细信息，以后如果您有兴趣，您也可以订阅更精细的付费证书课程。该技术在分析药品，食品，化妆品，环境样本方面具有很大的希望，临床和生命科学应用。
尊敬的先生，
在gc分析一些时间我们观察到峰值,may be suspected due to any disturbance at environment and power fluctuation. these are not merged with target peaks.so we are valid these chromatograms are valid with comment.
是我t correct practice or not can you explain me.
我希望这些尖峰是随机的，并且您不会重复注射。如果这些是随机的，则可以忽略它们。
Dear sir,
我该如何用正确的写作示意答案？
嗨，杰伊，
The article has provided you relevant information. You can summarize to write s short write up
先生，我想知道证书将在狂欢中的时间。
该课程没有时间限制。您可以按照自己的速度和便利来完成它。但是，我们的注册人通常需要2-3个月才能完成课程并回答评估课程
亲爱的Bhanot博士，
Thank you for the knowledge you always give to us. Please can I use ZR-PS column for histamine and other biogenic amines analysis? Which mobile phase will be appropriate. Thank you.
亲爱的辛斯特，
副手很难为特定应用程序推荐列或移动阶段。列的选择将取决于您的样本矩阵，浓度级别等，尽管在某些参考文献中使用了一些参考文献。您也可能会缩小实验室中可用的等效列。
Regards
It iz very usefull and i learnt basic concepts of HPLC and GC . Thanking you sir ! ☺️
Thanks Rupesh for the encouragement. It is a great feeling to know that the information has proved useful to you.
很好。我从中学到了很多。请如何注册证书课程。