Re: why does the prominant ion change from time to time?

do you want to perform quantitative analysis?
Try to use formic acid only (0.1 - 0.25 %) or 0.05 % TFA.




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} I'm study some taxans with a Finnigan Lcq Advantagesysterm. The
} prominent ion of some compounds changes from time to time. Sometimes
} it's [M+H]+ ,sometime it's [M+Na]+. Do you know how to resolve this
} problem? If I want to make sure that [M+Na]+wii be the prominent ion,
} need I add something to the mobile phase, what can I add? Thank you
} very much.
}
} the is listed below
}
}
} flow rate (ml/min)                                       0.8
} mobile phase component(ACN:Water)                        49:51
} Spray Voltage(kv)                                        5
} Capillary Temp(degree)                                   200
} Capillary Voltage(v)                                     5
} Tube lens Offset(v)                                      30
} Vaporizer Temp(degree)                                   480
}