Results of Exercise 7 (Accurate Mass)

The problem with this exercise was that if you committed an error on the way all consecutive steps were wrong. So I counted all correct steps and added a good bonus for work done and argumentation – although this is educationally questionable 🙂 In addition, the tools seems to have a problem with negative ionisation data which I discovered too late. The safe way is to calculate the molecular mass and take from there (always-! ). – We reached 74% of average possible points and I consider this fine, for your first HR data analysis.

StepTask 1Task2Task 3
Consideration of mass spectrumM+1=18% -> ca. 18 carbons. Mass defect .08 = Cl, Br, F, many O’s. M+2= 35% -> exactly one Cl and maybe one Sulfur. M+1=15% -> ca. 15 carbons. Mass defect 0.008 = Cl, Br, F, many O’s. M+2= 37% -> exactly one Cl and probably 1 SulfurM+1=27% -> ca. 27 carbons. Mass defect=0.27 = very few heteroatoms. M+2 =5% -> only carbon related = no Cl, no Br, no S
neutral mass
Constraints (proposal)
M = 284.072141
C15-20 H10-40 N0-10 O0-10 Cl1 S0-1
M= 330.007420
C12-20 H8-40 N0-10 O0-10 Cl1 S0-1
M= 408.287767
C20-35 H20-70 N0-5 O0-5 Cl0 S0 Br0
mass tolerance0.6mDa/285Da= 2.1 ppm = 2.5 ppm0.6mDa/329Da= 1.8 ppm = 2ppm0.6mDa/407Da= 1.5 ppm = 2ppm
mass to search285.079966 – 1.001852 =
284.072141 (M)
328.999595 + 1.001852 = 330.007420 (M)407.279942 + 1.001852 = 408.287767 (M)
ReflectionsChlorine containing natural metabolites are rare. The compound has only been found in the patient group = could be a drug. Check candidates for psychiatric drugs -> DiazepamChlorine containing natural metabolites are rare. The compound has only been found in the patient group = could be a drug. Check candidates for cardiovascular drugs -> FurosemidePresent in treatment and control = natural metabolite. Many carbons and few heteroatoms = lipid, steroid or sterol or ester thereof. Candidate list should contain cholic acid. Very likely to occur after high fat breakfast..

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