Reagent and method for detection of carboxylic acids by mass spectrometry
Method and reagent for converting a carboxylic acid to a positively charge amide are described. The method and reagent facilitate positive ion mass spectral analysis of carboxylic acids. The method includes reacting a carboxylic acid with a compound having formula I: wherein A and B are aromatic rings, ring A includes a quaternized nitrogen and has n additional ring atoms, each additional ring atom optionally substituted with an R A group, and n is an integer from 4 to 10, and ring B includes a carbon atom and has m additional ring atoms, each additional ring atom optionally substituted with an R B group, and m is an integer from 4 to 10. The compound includes at least one R A or R B group, and the at least one R A and R B group is -L-N(Z)H; and X − is a counterion.
1. A compound having the formula
wherein R 1 -R 10 are independently selected from hydrogen, an alkyl group, and -L-N(Z)H, wherein L is an alkylene, Z is hydrogen or an alkyl group including from one to twenty carbon atoms, provided that at least one of R 1 -R 10 is -L-N(Z)H; and
X − is a counterion.
2. The compound of claim 1 , wherein the compound is an N-(4-aminomethylphenyl)pyridinium (AMPP) salt.
3. The compound of claim 1 , wherein Z is H.
4. The compound of claim 1 , wherein L is methylene.
5. The compound of claim 1 , wherein R 1 -R 7 , R 9 , and R 10 are each hydrogen.
6. The compound of claim 1 , wherein R 8 is -L-N(Z)H.
7. A kit for derivatizing a carboxylic acid, comprising:
(a) a container comprising a compound of claim 1 ; and
(b) indicia providing instructions for using the compound to derivatize a carboxylic acid.
8. The kit of claim 7 , wherein the compound is an N-(4-aminomethylphenyl)pyridinium (AMPP) salt.
9. The kit of claim 7 , wherein Z is H.
10. The kit of claim 7 , wherein L is methylene.
11. The kit of claim 7 , wherein R 1 -R 7 , R 9 , and R 10 are each hydrogen.
12. A compound having the formula
wherein X − is a counterion.