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There are a few ways to confirm. 1. Confirm with the standard of the compounds. Run a standard of the compound, record and compare the mass spectra. 2. Based on the mass spectra of the compound, confirm the mass of ion fragments

@@shirwansany I mean when you click some peak many mass spectra is shown? I need to identify Z-7-dodecyl acetate ? how can i do that? Anyways thanks for your video.

Walaikumsalam. Here is my practice: 1. Collect the background's spectrum 2. Collect the sample's spectrum. 3. Deduct the background's spectrum from the sample's spectrum to get the actual spectrum. Usually, I set these activities to be the default setting of the FTIR spectrocopy so that I don't have to manually deduct the background's spectrum.

@@shirwansany Thank you for your prompt response. I find it difficult to know the settings from which I can set the automatic subtraction of background spectra from the samples. Also, I am worried that if I use the subtraction tool after measuring, the background would be subtracted twice. It is strange to me that non of the available information about OMNIC even the one shared by the maker talks about the subtraction of the background. Please teach us more about it when you have time.

Dear @NellyGraceTonacao, thank you for your comment. I have limited experience with Unscrambler X even though I have the software version 10. Hence, I do not have recorded video using this software. This version does not have PLS-DA but only linear discriminant analysis (LDA). I used to carry out PLS-DA with XLSTAT. However, handling big data FTIR with XLSTAT is challenging compared to Unscrambler X. You may contact me via shirwansany@iium.edu.my. Perhaps we could collaborate soon.

Hello @javajoe4, thank you for your comment. The 'select signal' will activate if you set the GC/MS to record the chromatogram in both scan and sim modes. If you do not select the sim mode before analyzing the sample, the GC/MS will record the chromatogram in scan mode by default.

With GC/MS, you can identify a compound with (2) Mass spectra of the compound and (2) retention time.

Hi @abdullahimuhammad6591, thank you for your comment. Hello, yes possible to use relative abundance instead of area.

Hi @raahis8256, thank you for your comment. I recommend you analyse both blank and sample. Then, the blank chromatogram is deducted to get clean mass spectra. From the mass spectra, you could deduce the possible compound based on the mass spectra.

Salam, GCMS can identify the volatile compounds in the plant. Here is the strategy: 1. Analyze the plant extracts via GCMS. Determine the detected compounds, qualitatively. 2. Based on the detected compounds, purchase the compound standards. 3. Analyze the standards via GCMS and set up a calibration curve for each standard. 4. Analyze the plant extracts. Then quantify each compound using the calibration curve.

You can purchase from the xlstat website: www.xlstat.com/en/pricing/student

Hi John. We have. Kindly drop an email requesting the training at inhartlab@iium.edu.my

@@shirwansany8706OK

hello did you get the ans for this question???? i am also confused

I have the same question as well.

@@rahanjdas5572 nope

@@scientiainquisitor5391 thanks for letting me know

You'll never be able to be 100% sure. Here, the mass fragmentation pattern (and retention time I guess) is (are) compared to the library to find the best matches. You can see a value to the right of the proposed molecules (in the column called "qual" for "quality") which is a percentage score. The closer it is to 100, the better the match between the data acquired and the library. Also, here are displayed only the 3 best results from the library but there are more for sure. In that case, the quality score is high enough to be fairly certain of the identity of the molecule, but sometimes, when the sample is more complex (and when you have co-elution of several compounds), the library struggles to find good matches and it can be useful to consider more possible matches.

Hello, this is Enhanced Data Analysis software from Agilent, which came together when we purchased the GCMS.

Salam, Thank you for the question. I have not recorded the video on the index calculation, but I have published the work here: link.springer.com/article/10.1007/s41664-020-00118-z. Shall you need the paper, please request via shirwansany@iium.edu.my

@@shirwansany8706 jzak ALLAH for response. Can we match our calculated Kovat retention index for (HP-5) with the theoretical/literature retention index (HP-5) of Kratz?

@@somiaafzal6807 possible; However, you may need to follow the GC similar setting from the previously reported retention index. Also, please allow some deviation from the previously reported retention index.

@@shirwansany8706 Jzak Allah for the answer. So the point that is confusing me is that the calculated retention index (Kovats' RI) can be matched with the previously reported/theoretical/NIST chem book etc. Van Den Dool and Kratz RI retention index OR with the Normal alkane RI. So only need to match our GC setting and column type (like HP5 / DB wax type etc.) and find the nearest RI?

@@somiaafzal6807 The approach is as follows: 1. Find the original work the calculate the Van den Dool and Kratz RI 2. Follow the GC setting and procedure to get the RI. 3. Compare your calculated RI with the published Van Den Dool and Kratz RI. Else, you also can compare with NIST, Chem Book RIs. The NIST and Chem Book RIs have stated with column they used. Compare the RI of compunds that are separated using the similar column.

Silakan bertanya.