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Questions related from Xiaofang Yuan
Hello, everyone. I found the bacteria I cultured can be inhabitated by another bacteria when I culture then together in the plate. Now, I want to analyze which metabolite contribute to the...
24 December 2018 7,046 2 View
I want to use ropls package to get PCA, PLS DA, OPLS DA plot. But I don't know how to arrange data to get PLS DA plot. The introduction mentioned that "Y resonse should be used" but I don't know...
10 November 2017 883 1 View
I want to use ropls package in R to make PCA, PLS DA, OPLS DA plot, and get R2, Q2, VIP value. Anyone know how to use it? I have download introduction of ropls, but I want to get detail R script...
09 October 2017 4,864 4 View
I want to analyze TCA cycle, but pyruvic acid, glyoxylic acid cannot be detected. My GC MS is 7890A-5957C, HP-5MS column, MTBSTFA as derivatization reagent, Anyone can give some advice?
17 August 2017 6,764 3 View
I want to detect TCA cycle intermediates, pyruvate, glyoxylic acid with GC MS, I have MTBSTFA, after derivatization, pyruvate, oxaloacete and glyoxylic acid cannot be detected, does anyone know...
14 July 2017 5,076 17 View
After culture cell, I want to analyze metabolites in medium, but there are a lot of metabolites in medium, how to extract metabolites in medium?
26 June 2017 5,664 7 View
I am analyzing metabolites content in yeast and E.Coli, after exraction with ACN:H2O, and drying with freeze dryer, then dissolve in ACN and MTBSTFA to derivatize amino acids. But it is hard to...
06 April 2017 8,823 2 View
Some amino acids, serine, threonine, tryptophan, have double derivatives after derivatized by MTBSTFA (with GC MS), To get a good standard curve and quantification result, how to calculate peak area?
04 April 2017 6,155 3 View
When I use freeze-dryer, after freeze at -80C for 5 or 7h, drying it but there are always sample loss after drying, some of the dried sample get out of the glass tube. How to avoid the loss?
30 March 2017 780 7 View
I am planning to analyze amino acids content in LB medium, is it necessary to extract from the medium? which solvent is better to extract?
13 March 2017 2,477 0 View
After derivatized with MTBSTFA, some amino acids have 2 derivatives, like tryptphan, cysteine and threonine, defferent number of hydrogen were derivatived. Does anyone know the reason and how to...
05 March 2017 7,343 1 View
I am analyzing 20 amino acids now with ethyl chloroformate and MSTFA which is two steps derivatization. Based on the reference, they use ethyl chloroformate and MTBSTFA , but I don't have MTBSTFA...
20 February 2017 1,070 3 View
I use HCl to dissolve amino acids, can I dry the solution with freeze dryer?
20 December 2016 6,378 14 View
I analyze 20 amino acids in yeast now, but there are many problems. I cannot separate proline-isoleucine peaks, and cannot detect argnine, glutamine peak. Who have ever did this research ?
08 December 2016 8,212 3 View
I am a beginner in R language and I want to analyze metabolomics data with R. Recently I found an R package "muma" which is for metabolomics data analysis but I don't know how to use that package....
01 January 1970 7,779 5 View
When I analyze 20 amino acids with GCMS, I use MSTFA to react with sample, but there are some combined peaks cannot be separate. Like proline-Isoleucine, and i cannot detect tryptophan and...
01 January 1970 4,110 12 View
