search for: hplc

Hello! I am having an issue with the OrgMassSpecR package. I run my HPLC using a DAD detector. My raw data is exported form chemstation as a csv file. I then upload the csv into Rstudio no problem. Using the DrawChromatogram function, I get a nice chromatogram, and my retention time, peak area, and apex intensity values are given as well. The problem comes with the...

http://r.789695.n4.nabble.com/file/n3312061/x_and_y_values.txt x_and_y_values.txt I have the absorbance values form HPLC Chromatogram. I need to find the peaks in datapoints and area under each peak. I am not sure how how to find the peaks, I tried couple of libraries and peak function but they return me a list of values which when computed from area turns out to be huge nnumbers. In the dataset I know there are 4 p...

...15.93, 15.94, 15.91, 15.95, 15.92, 15.93), expand.grid(INJ = factor(1:3), VIAL = factor(1:4), STD = c("EXT","INT"), SEQUENCE = factor(1:2))) representing the outcome of an HPLC analysis (PPM) as from 2 sessions (SEQUENCE) in which 2 methods were used (with EXTernal or INTernal STanDards) 4 VIALS were analyzed by 3 INJection each I need to calculate some values for each of the combinations of the factors like aggregate(My.df[1], by = list(SEQ=My.df$SEQUENCE, ST...

...that the prediction be within 15% of the original value. In my opinion it is *very strict* - I actually used 20% in my work. This is because of very high variability and imprecision in the results themselves. These are real biological data and you have to account for errors like analytical errors (HPLC method), timing errors and so on, when you look at these data. In other words, if you take two blood samples at each time-point from a particular patient, and run them, you will 100% certainly get two distinct (although similar) profiles. You will get even more difference, if you run one set of sam...