液質聯(lián)用中質譜條件的優(yōu)化策略(存儲版)
【正文】 Auxiliary Gas: 0? Capillary Temp (176。C 2023006000001000000AbundanceWithout TFAFix 2023006000001000000minAbundanceWith TFAFix1:2 postcolumn addition of 75% propionic acid in IPATryptic Digest Map by ESLC/MS1 nmol Chicken LysozymeSignal Suppression due to Additives? Ion pairing with analyte, surface tension effect? Solutions:– Postcolumn addition of a sheath liquid of propionic acid (10%) in 2propanol (TFA Fix)– Use low concentrations of TFA with acetic acid (TFA Light)– Replace TFAESI signal suppression by TFA 01122Achievement of gaseous analyte ionization at API interface is the key to MS detection離子化方式216。 B – methanolGradient: 5% to 75% in 4 minMobile Phase pH effect on ESIColumn : HyPURITY? C18 5?m, Aqueous mobile phases:% Formic acidpH 3, Ammonium formate 20 mMpH 5, Ammonium acetate 20 mMpH , Ammonium acetate 20 mMpH 9, Ammonium acetate 20 mMAqueous/methanol (50:50)Flow rate: ml/minTemperature: 25176。C, , 20VScan: 120 – 480uAnalytes:NortriptylinePropranololTetracyclineCaffeineParacetamolTryptophanSalicylic acidNicotinic acid01113Effect of Mobile Phase pH on +ESI Response01115Effect of Mobile Phase pH on ESI Response01116Solvent System50/50 MeOH/H2O50/50 ACN/H2O100% H2O100% MeOH100% ACN50/50 MeOH/H2O 1% Acetic50/50 MeOH/H2O % Formic50/50 ACN/H2O 1% Acetic50/50 ACN/H2O % Formic50/50 MeOH/H2O 5mM NH4OAc50/50 MeOH/H2O 10mM NH4OAc50/50 MeOH/H2O % TFA50/50 MeOH/H2O % TFA50/50 MeOH/H2O % TFA50/50 ACN/H2O % TFA50/50 ACN/H2O % TFA50/50 ACN/H2O % TFA50/50 MeOH/H2O % NH4OH50/50 ACN/H2O % NH4OH0 100000 202300 300000 400000 500000 600000Ion Signal, Counts [M+H]+Solution Chemistry Effects on Positive Ion ESIMS of LeuEnkephalinLC/MS Sensitivity vs. Mobile Phase ModifierGluC Digest of BS5% Acetic% TFA% TFA% TFAZorbax 300SBC3( x 150 mm)HP1100 MSD? Reversedphase HPLC/MS analysis of a GluC digest of BSA was used as a model to test the recovery and peakshape of peptides using varying concentrations of TFA or 5% acetic acid as a mobilephase additive in bination with the Zorbax 300SBC3.? Digestion of BSA was carried out 37176。 非極性化合物多采用大氣壓化學電離源（APcI）（激素），原則上不建議采用添加其它化學試劑Steps for ESI Optimization? If analyte’s pKa is unknown, evaluate 3 pH regions in positive and negative ion mode
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