液質(zhì)聯(lián)用中質(zhì)譜條件的優(yōu)化策略(已修改)
2025-03-05 09:03 本頁面
【正文】 液質(zhì)分析條件的優(yōu)化策略（簡化板）液相色譜與液質(zhì)聯(lián)用儀使用的要點(diǎn)? 質(zhì)量校正的正確? 對于相關(guān)分析要有合適的支持軟件（ Max，TargeLyness）? 合適的液相色譜平臺? 合適的質(zhì)譜接口方式? 液相色譜分析中合適的色譜柱的選用? 質(zhì)譜檢測模式的選擇? 必要的后液流補(bǔ)充質(zhì)量校正的正確（ Myoglobin校正）質(zhì)量校正的正確（ Myoglobin校正）質(zhì)量校正的正確（ CsI校正）的肽測定質(zhì)量校正的正確（ CsI校正）的蛋白測定質(zhì)量校正的關(guān)鍵點(diǎn)? 針對不同的分析采用不同的校正，一般蛋白質(zhì)采用 Myoglobin，對于小分子分析建議采用 CsI校正。? 對于采用 Myoglobin校正的建議采用高次方的校正曲線（ 34）；對 CsI校正的建議采用低次方的校正曲線（ 12）合適的液相色譜平臺? 能提供一個連續(xù)、穩(wěn)定的液流環(huán)境? 真空脫氣設(shè)備? 系統(tǒng)的死體積盡可能小，減少管路的長度? 輸液泵的設(shè)計能適用于微徑柱的要求? 二極管陣列檢測器的池體積與質(zhì)譜儀匹配? 必要的液相色譜輔助配件? 必要的液相色譜與質(zhì)譜儀的軟件操作平臺合適的液相色譜柱? 柱內(nèi)徑： ? 柱長度： 根據(jù)分析的目的選擇 50mm或 150mm? 柱填料選用新型的填料： Symmetry， Discovery， Vydac， Zorbax，Xterra， Intersil， Diamonsil等LC/MS Flow Injection Analysis of Peptides and Proteins by ReversedPhase HPLC% HOAcminAbundance 50000100000150000202300250000% TFA 50000100000150000202300250000minAbundance? ReversePhase LC/MS Solvents– ACN, MeOH, H2O, Isopropanol? NormalPhase LC/MS Solvents (for APCIMS)– Hexane, Methylene Chloride, Acetone, Ethanol ? Compatible LC/MS Buffers and Modifiers: – Formic acid, acetic acid, ammonium acetate, ammonium formate, ammonium hydroxide, trifluoroacetic acid– TFA concentration should be % v/v– Keep volatile buffer concentrations 20 mM to minimize ESI ion suppression? Avoid Nonvolatile Buffers– Alkalimetal phosphates, borates, etc.Suitable Solvents for LC/MS? Volatile buffer – minimize instrument downtime? Buffer concentration: – High ? ion suppression decreases ESI sensitivity – Low ? system adequately buffered?? pH range permitted by stationary phase? Methanol or acetonitrile– Start with acetonitrile 01111Change Retention to Improve Resolution – Select Solvents/ Modifiers that are MS CompatibleUseful pH Ranges for Volatile BuffersBuffers normally used in LC/MS :01094Buffer pKa pH rangeFormate – Acetate – – Triethylamine 10 – 12 Diethylamine – ???Ammonia7 6 – 8Buffer Concentrations/Additive amounts: ? 10 to 50 mM? formic, acetic acids 1% v/v? trifluoroacetic acid % v/v? alkylamine type bases % v/vEffect of Buffer on Analyte ResponsePhosphate buffers suppress the MS response of caffeine at all pHs and also the MS response of Oxazepam at pH 8. Volatile buffers (formate, acetate, ammonia) generally provide good responses. 01121Mobile phase: A 10mM buffer pH 。 B – methano
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