液相色谱分析条件摸索？Some general guidelines are as follows: If your target analyte is an acidicanalyte (pKa 3), use a 0.2 v/v% phosphoric acid mobile phase. If targetanalyte is a basic analyte (pKa 7–9), use an ammonium acetate buffer (pH5.8) to analyze in its ionized form or use a 25mM ammonium hydroxide buffer(pH 10.5) or 25mM N-methyl pyrrolidine buffer (pH 10.5) to analyze in itsneutral form. Use a 10-cm × 3.0-mm column packed with 3-μm particles andintermediate polarity phase such as a C8 column that is stable for the pH atwhich you may be running the probe separation. Run in the gradientmode using an acidic buffer or a basic buffer from 5% to 95% of organiccomponent, or up to the buffer solubility limit over 10 min, and use anisocratic hold for 10 min to ensure elution of hydrophobic components. Use aflow rate of 0.8–1 mL/min flow rate and 40°C temperature. Injection volumeshould be on the order of 5–20μL and the concentration of the analyte shouldbe 0.5–1mg/mL. This corresponds to approximately 5–20μg injected oncolumn. On the other hand, for neutral analytes higher analyte loadingsuch as 50–100μg maybe used since nonideal interactions with the stationaryphase are less prevalent. Note that for ionizable compounds, especiallybasic compounds when analyzed in their ionized state, higher mass on columnmay lead to mass overload of “hot spots” on the bonded phase and poor peakefficiencies may be observed. Try not to load more than 10μg on columnfor basic compounds. Usually greater loading capacity is obtained for basiccompounds when they are analyzed in their neutral state. Note that forcolumns with larger inner diameters such as 4.6mm, larger sample loads maybe acceptable如果你对这段话感兴趣，这本书下下来自己看，查看更多
第1天
关注盖德视界
添加小助手
