Muhammad Ayub

9 Questions 18 Answers 0 Followers

Questions related from Muhammad Ayub

Error in Detector calibration in GC-MS/MS?

Hi experts, yesterday I tried to Calibrate/Autotune GC-MS/MS detector, and after sometime it gave error with the message "EDR error, not enough signal". I tried many times but still problem...

22 May 2021 4,979 2 View

How I can achieve maximum percision in pesticide analysis on GC-MS/MS?

I used pesticides mix standard for repeatability study, and observed the area of peaks increasing with sequence injections while injecting from same vial. The %RSD is between 8 and 14 for...

06 May 2021 8,949 8 View

How to increase signal response in GC-FID?

Dear researchers and Experts! In GC-FID i run the FID CAP test standard which include C14, C15 and C15 FAME's. The resonse factor is very low and the area of peaks also very small. can anyone...

11 December 2020 6,932 7 View

What is the EPA/WHO Maximum Residual Limit (MRL) for pesticides in food?

I searched on internet to find out the MRLs values for pesticides in food but not found any authentic data, can anyone please share link or pdf file of EPA/WHO MRLs standard for pesticides in food.

13 November 2020 5,206 8 View

How to resolve base line issue in GC-MS/MS?

In GC-MS/MS pesticide analysis the base line is neither starting from zero nor it is straight even it is fluctuating from peak to peak. Baseline also vary when changing selected ions in SIM scan....

24 September 2020 6,418 4 View

How we can eliminate background signals/noise in GC-MS/MS?

In GC-MS/MS I run the pesticide mix standard (in Acetonitrile) using SIM mode in which sharp well seperated peaks appeared, but there are ups and downs in base line. The same problem comes when...

09 September 2020 4,028 6 View

In GC-MS/MS which scan mode is best for validation study?

During validation study I choose full scan and SIM mode. For both scan it gives different peak area for same analyte (pesticide) of same concentration and in SIM it gives less peak area than full...

29 August 2020 4,474 9 View

Is it possible for single analyte to show two peaks at different retention times in GC-MS/MS?

I run full scan for Dimethomorph (a fungicide) in GC-MS/MS, and it gives two peaks with different retention times 11.1 and 11.3. I increased temperature from 280 to 320°C and peaks little bit come...

20 August 2020 3,880 3 View

What is meant by 'Precursor' and ' Product' in MRM mode using GC-MS/MS?

In pesticide analysis I used MRM mode in MS method, and it asks about precursor and product. I used default values as precursor at 272 and product at 222 m/z for analyte I used Benomyl (a...

12 August 2020 7,706 10 View