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SanTo ☆ Indonesia, 2019-05-03 06:55 (1817 d 10:25 ago) Posting: # 20268 Views: 3,258 |
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Hi, We have tried to develop a bioanalysis method of isosorbide mononitrate but it has not been successful. When tuning with LC MSMS, the parent ion intensity is e7 while the intensity of the daughter ion is e5. What we have done is with negative ESI at m / z 249.92> 59, with column C18, the mobile phase used is methanol and ammonium acetate. Our target is 3.5 ng / mL in human plasma but when injection of samples in the solvent (not extracted) the area is not present. Please help solve our problem. Thanks. |
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cakhatri ★ India, 2019-05-28 13:13 (1792 d 04:07 ago) @ SanTo Posting: # 20303 Views: 2,475 |
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Dear SanTo, The molecular weight seems to be 191.139 g/mol. How did you get 249.92 for parent compound. Regards Chirag |
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SanTo ☆ Indonesia, 2019-06-17 15:15 (1772 d 02:05 ago) @ cakhatri Posting: # 20328 Views: 2,292 |
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Dear cakhatri, The formation of the ion was observed in negative mode corresponding to an adduct with the acetate anion (M + acetate)- of m/z 249.9, whose abundance is higher than deprotonated molecular ion (M-H)- of m/z 190. Regards SanTo |
Ing. Helmut Schütz