i laughed so hard at the "Our favourite molecule, cocaine" part

Thank you so much, professor! It really helps me in my internship primarily focused on analytical instruments and research on biological samples using mass spectrometry methods. Absolutely grateful that I found your channel and it helps me understand complex concepts that I've been trying to grasp for a long time. And you have summarized it well! Thanks again!

I came here out of my course syllabus but i only just now read about your relation to Coach Greg. Whoa! I am now starting to see the resemblance. It's so nice to have came across your channel too. 🙏😊

"Let's say you have our favourite molecule now - Cocaine!" That surely drew me in! 🤣

really like the way you explain, make it much easier to understand when im not a native english speaker ! thank you so much appreciate your work !

Smarter than last time?

Interesting video, professor. Glad to have learned something new today.

High professor, your twin Coach Greg brought me here. It takes a lot of work and courage to put yourself out there for the world to see. Keep up the good work and best of luck with your channel. Does Steve edit your vids too?

Appreciate your clear explanations!

Thank you very much! Your videos are very clear, keep them up

Sir thank you so much for all of your time and effort these videos and your channel have helped me so much in my career as a chemical engineer and Equipment specialist God bless you and I wish you the absolute best

you actually saved my life!!

More chemistry than last time

Thank you Dr. Doucette! Very good video I Subscribed

Fantastic video!

Yes yes yes! Nice explanations!

I like your methods for teaching makes you want to learn rather than just as a part of coursework

Very clear! Thanks

Thank you so much!

great! thanks a lot!

you saved my life

Hey buddy just came here from your brother Gregg’s channel to check your channel out

@bobjoe9188

3 жыл бұрын

Same

Tysm

Hello. I would like to ask you for advice. Does the mobile phase have a major effect on the optimization of the mass spectrometer? When optimizing the mass spectrometer, I chose a mixture of acetonitrile and water as the mobile phase. However, when optimizing the HPLC method, I chose a mixture of buffer and methanol as the mobile phase. I would like to know if the change of the mobile phase has an effect on the mass spectrometry (finding of precursor and product ions, voltage of ion optics and collision energy)

@shortchemistry7927

3 жыл бұрын

Definitely there is an effect. Both for LC and for mass spec. You may find differences in retention, including changing the elution order of certain compounds. The biggest change usually relates to the addition of pH modifiers, and ion pairing agents. Trifluoroacetic acid is great for LC, but causes severe suppression in MS. Switch to acetic or formic acid instead. Non volatile buffers (and even volatile buffers such as ammonium acetate) can also reduce signals. EsI is aided by volatile solvents, so be sure when switching from methanol to acetonitrile that you still have an appreciable amount of organic (20% or more) to maximize signals.

HI!New fan of this channel! Could ypu please let me know if the Precursor Ion Scan can e also done in other Mass spectrometers others than triple quad? how would it be for example in ORBITRAP?

@alandoucette9997

2 жыл бұрын

Thanks for your question. Historically, tandem ms was built on triple quads. And it also serves as a good starting point to teach the concepts. But newer MS platforms seem to be taking over. A good example is a QqTOF, which simply swaps the last quad for a Time of flight. This machine can do anything a triple quad can do, and more (specifically, high res MS, and faster scanning). Orbitraps are also taking over the industry, and also can do the same job as triple quads and then some. Keep in mind that Orbitraps also involve other components that roughly mimic a triple quad (I over simplified the full platform). So, to sum, yes, many other instruments can perform the types of scans available to triple quads. Including the orbitrap.

Question; what is the ideal lc-ms/ms in the market for therapeutic protein characterization right now? Thanks

@shortchemistry7927

3 жыл бұрын

I would say that really depends on the specific goals of the analysis. Are you looking for purity? Stability? Sensitivity? Throughput? Personally, I am excited by what top down proteomics can offer, which implies instruments with high resolution and alternative fragmentation beyond CID. So for that, you're looking at Orbitrap or FTICR (possibly QqTOF). But a conventional QQQ will be great for MRM assays. In terms of vendors, everyone has their favorites. And certainly, each has their advantages. I think establishing a relationship with the vendors, to see how they can assist in terms of training, technical support, upgrades, and ancillary equipment etc... should all factor into a buying decision.

In a triple quad. LC/MS-MS experiment where we set the first quadrupole to only allow the mass ion of the target analyte to pass through, so that it is fragments in the collision cell, will the mass spectrum from the second quadrupole be equivalent to a mass spectrum obtained on a GC-MS single quad system that uses EI ionization? In other words, can LC/MS-MS be used to create mass spectral libraries that can be used for compound identification by EI GC-MS? Thank you.

@shortchemistry7927

3 жыл бұрын

Wow, great question! Technically, the ion being fragmented in a triple quad is different that in a gc/ms experiment. That's because ESI usually protonates our molecule while EI deals with a radical ion, missing one electron. It may seem like a subtle difference, but the way radicals behave will be different. You tend to see similarities in these spectra, although with ESI the fragments are also shifted up by 1 u.

@Ambient_Scenes

3 жыл бұрын

@@shortchemistry7927 Thank you for the answer! So would a tripple quad give enough fragmentation do be able to do structure elucidation (at least of small molecules)?

@shortchemistry7927

3 жыл бұрын

@@Ambient_Scenes Most definitely. Any system capable of tandem MS could be used. Or a system that creates fragments through ionization (EI)

@Ambient_Scenes

3 жыл бұрын

@@shortchemistry7927 Thank you for the answers!

Owh plz sir make more of those videos

Plz sir can u make a video about tandem spectrometry and the use of it in biological or clinical analysis

Thank you, Very helpful video. Can you explain the difference between ICP-MS and ICP-MS/MS?

@shortchemistry7927

3 жыл бұрын

Good question... because normally we think ICP breaks everything up into single atoms. So what is left to fragment? Well actually, ICP doesnt always break up everything so you can still be left with a few specific molecules (ie polyatomics), with a mass that coincidentally is the same as your analyse. These interferences are a big problem and need to be eliminated. Enter MS/MS, which allows you to break up the polyatomic compounds and basically allows you to separe the signals of the good stuff vs the junk in the background

Some segments in the video are stamped not adjacent to each other

kucch samajh nahi aaye chee. ek to pehle se hi kucch nahi hota , upar se aur sab upar se jaaye chee

@bogo_indian

2 ай бұрын

Tereko English nahi aati wo bol