some tips:
1.generally, when we run a sample set, i think its better for us to set the injection times of the first row to be 2 because i have met some conditions that all the samples in the same sample set has a perfect reproducibility but the first one. i think there r many factors involved in, such as the condition of the colomn and the UV lamp, or the suitibility of the whole system. so, i consider its a better choice for us to let the first sample run two times to achieve a good result. it is a good method for us to check out wether the variety between the first row and the others comes from the sample itself or comes from our system unstability.
2. very often the injection volumne is 10 ul in HPLC. but in my own experience, i have to inject some volumes like 1,2,3,4 ul, and i found that the accuraccy is poor, although i got a R and R^2 of something like 0.9998, especially when the injection volume is below 1 ul, the accuraccy is too poor to be trusted and validated. so, its reasonable to inject the common 10ul i think, and better for us to avoid a small injection volume.
3.when we make sample preparation, better for us to chose glass flask and bottles but avoid the plastic ones, especially when we prepare standard liquid in which there are small amount of standards and easily to be affected by impurity.
还讲到以下概念:
Collection Valve Switch Time
Detector Time Constant
Using a DMSO Solvent Sandwich
Delay Volume My heart
Method Used to Determine Delay Time
Software Processing Speed
Delay Volume (II)
Delay Volume (III)
Optimizing Purifled Sample Recovery on Reverse-Phase HPLC Systems
cuturl('http://www.antpedia.com/?uid-35804-action-viewspace-itemid-146068')作者: lian1982800 时间: 2011-5-31 11:50
关于ELSD的线性
开始做ELSD时没有知道这一点:ELSD的amount and area之间不是线性的,如下所述:
ELSD provides a non-linear response, resulting from the various light scattering mechanisems and from the particle size distribution. the non-linear ELSD response is described by the widely used empirical model.
y=am^b,where m represents the amount injected, and a and b are numerical coefficients.
所以在做calibration curve时,应该选择log-log的方式,得到y=a+bx的直线,其中Y代表log value of the peak area, and X the log value of sample amount, a the intercept and b the slope.
根据自己的结果,这样子出来的结果还是很不错的。
reference:
analyst,2002,127,35-41
另外还有两篇介绍ELSD基本原理和应用的文献,比较早:
1。journal of chromatography,265(1983) 1-18
2.journal of chromatography, 288,(1984) 253-275作者: fengyan22 时间: 2011-5-31 11:52