FAQ and Troubleshooting

Q1 What is the pressure limit of COSMOSIL columns?
Q2 What is the flow rate limit?
Q3 What is the recommended pH range?
Q4 What is the concentration of buffer and salt?
Q5 How do I prepare the mobile phase?
Q6 What solvent grade should I use for the mobile phase?
Q7 Should I use acetonitrile or methanol for the mobile phase?
Q8 Which mobile phase can be used for LC/MS or ELSD detector?
Q9 What should I pay attention to when using ion-pairing reagents?
Q10 What flow direction should I use for the mobile phase?
Q11 What is the recommended column oven temperature?
Q12 What is the shipping solvent?
Q13 How do I wash columns?
Q14 How do I store columns?
Q15 How long does a column last?
Q16 What happens when a column deteriorates?
Q17 How can I confirm the deterioration of column?
Q18 What should I pay attention to when I use semi-micro columns?
Q19 What should I pay attention to when I use UHPLC columns?
Q20 How much sample can be loaded on a preparative column?
Q21 What should I pay attention to when I use both reversed phase and normal phase on the same instrument?
Q22 What is the connection type?
Q23 Which detection methods should I use?
Q24 What is the common pressure unit?
Q25 What is dead volume?
Q26 What is the difference between a column pre-filter and a guard column?
Q27 How do I pre-treat samples?
Q28 How should I choose internal standards?
Q29 How should I select a stationary phase?
Q30 What is the difference between π-π interaction columns (PE-MS, πNAP, PYE)?
● Troubleshooting
T1 Poor peak shape
T2 Ghost peaks
T3 No peak
T4 Unstable base line
T5 Unstable retention time
T6 Increased column pressure
T7 Unstable pump pressure
T8 Poor resolution on C18 columns
T9 No retention on reversed phase columns
T10 Excessive analysis time on reversed phase columns
T11 Different separation performance compared to the past
T12 Different separation performance with a new column
T13 Colored elute from columns (colorless sample)
T14 Air got inside the column (dried out)