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3
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1answer
46 views

How can I reverse engineer a commercial cleaning solution's “other ingredients”?

I have a commercial lens cleaning solution. The manufacturer of the solution claims it is not only distilled water and that the formula is confidential. I suspected it was only or mostly distilled ...
0
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2answers
50 views

What is the process involved in performing a mass spectrometry experiment?

I have heard that mass spectrometry is very time consuming: why is this? What is the process involved in performing a mass spectrometry experiment? What steps are the most time consuming?
3
votes
3answers
98 views

Where does the characteristic peak for pthalic acid diethyl ester at m/z 149 originate?

Which fragmentation is possible at this m/z value for phthalic acid diethyl ester? I tried mac- Lafferty but it didn't solve my problem.
1
vote
1answer
42 views

ESI & MALDI Mass Spectrometry: particle mass vs. measurement error

For MALDI or ESI mass spectrometry of large macromolecules (e.g. in the $\approx 100$ kDa to $\approx 10 - 100$ MDa mass range), I've always how measurement error scales with particle mass. Not ...
4
votes
3answers
76 views

Could someone please explain the difference between m/z and m/e in mass spectroscopy

The definition: The abbreviation m/z is used to denote the dimensionless quantity formed by dividing the mass number of an ion by its charge number. It has long been called the mass-to-charge ratio ...
0
votes
1answer
74 views

Difference between an absorbance, emission, and excitation spectrum for uv-visible spectroscopy

The exam paper answer is 500, because we need the wavelength of "maximum absorbance." But this graph shows two curves, and the absorbance curve is omitted. But what is the difference between an ...
0
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1answer
117 views

How to calculate m/e value for the base peak in mass spectroscopy?

My working out: Propan-1-ol : CH3CH2CH2OH This can be broken up into: CH3 + CH2CH2OH CH3CH2 + CH2OH CH3CH2CH2 + OH Base peak = most abundant fragment formed (highest peak) How do i know which ...
0
votes
1answer
26 views

Calculate accelerating voltage required to separate two particles in a magnetic sector analyser

So, in mass spectrometry we have the following equation to describe a magnetic sector analyser, $$\frac{m}{z}=\frac{B^2r^2e}{2V}.$$ Lets say that I have two particles with different mass/charge ...
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2answers
61 views

1H-NMR and deducing structures

here is the data booklet we must refer too: Here is the exam paper solution: I dont understand how they conclude this. Peak areas and the chemical shifts seem to be different for me. For ...
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0answers
21 views

ESI MS/MS: Fragments are different in LC-Water and Sample

I'm no chemist and maybe someone of you has an explanation? I'm running a HPLC ESI MS/MS triple quadrupol with the solvents TDFHA and Acetonitril and reverse phase column. The conditions are not ...
1
vote
2answers
77 views

How does mass spectroscopy of nicotine work?

Take this nicotine molecule: And this mass spectrum: I'm not sure how to explain all the peaks. This might explain the peak at 42: But can this peek als be explained by something else in ...
2
votes
1answer
103 views

What's the difference between mass spectrometry, mass spectroscopy, and mass spectrography?

It seems that the terms mass spectrometry, mass spectroscopy, and mass spectrography are mostly used like synonyms. Is this correct? Or is there a difference?
3
votes
1answer
97 views

Looking for raw interferogram data / raw FID data from FT-IR / FT-NIR / FT-NMR

I'm trying to get my hands on some raw interferogram data / raw FID data from an FT-IR / FT-NIR / FT-NMR so I can run some tests using FFT with it (it needs to be real data). Here's a picture below of ...
0
votes
1answer
241 views

Mass spectrometry: trouble with acetic acid fragmentation

I'm trying to do compound optimization for acetic acid on a EI-MS. Later on it would be also run via HPLC to the MS. But I do only get fragments of 53/54 and 32. Also I need a high concentration to ...
2
votes
2answers
178 views

Interpretation of the following mass spectrum

I'm given the above spectrum. $M^+ = 102$, probably $\ce{C_6H_14O}$ or $\ce{C_5H_10O_2}$. I'm thinking of ethyl propionate. (that picture also shows the fragments I expect). I can account for the ...
1
vote
1answer
81 views

How to interpret a MALDI mass spectrum?

I have some questions regarding how to read a MALDI mass spectrum in a paper. I am a biologist by training, so I would like some analytical chemists to help me out. The researchers ran a western ...
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vote
0answers
35 views

Mass Spectrometry configurations

If MALDI is used as an ionization method, then TOF as an analyzer is suitable since the MALDI creates singly charged ions which have high m/z ratio and only TOF can analyze that ions, and multichannel ...
3
votes
1answer
205 views

What is the substituent on this benzaldehyde? (MS attached)

I have no clue what the substituent may be. The molar mass of the unsubstituted benzaldehyde is 105g/mol (subtracting one H, where the substituent will be). So the substituent is around 30-33g/mol. ...
9
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1answer
155 views

Understanding how mass spectroscopy works

I’m trying to get a deeper understanding of how mass spectroscopy works. Most tutorials and textbooks I’ve encountered omit certain details about the process and I’m hoping someone out there who ...
4
votes
2answers
734 views

How long does it take to run a MS/MS experiment

I am not planning to do these types of experiments but I would like to know the order of magnitude of the time it takes to run an LC-MS/MS experiment. Let's assume that I have the sample prep ...
9
votes
1answer
3k views

Resolution in Mass Spectrometry

I have been reading about resolution in Mass Spectrometry and there are a few things I do not understand. The resolving power is determined by m/(m2-m1) at full width half height of a peak. The ...
10
votes
1answer
555 views

What do typical results from inductively coupled plasma mass spectrometry (ICP-MS) look like, and how do I interpret them?

I have a degree in chemical engineering and remember having seen a inductively coupled plasma mass spectrometer (ICP-MS) during the laboratory part of a chemistry course I took while at university, ...
6
votes
2answers
2k views

Gas chromatography/mass spectrometry: Can I use peak ratios and molecular mass to derive quantity?

Can derive the quantity of a substance from a GC/MS report if I know: the ratio to another substance in the data, the quantity of that second substance, and the molecular mass of both substances. ...