Table 1.
MALDI analyte/matrix spots | Cause | Comments | ||
---|---|---|---|---|
• | Clear, translucent sample spots with no crystal definition | Excess base (NaBH4 + NaOH) from β-elimination reaction | SPE cartridge requires more thorough desalting with H2O prior to elution of glycans | |
• | Poor MALDI-FT-ICR-MS data | |||
• | Dark sample spots with no crystal definition | Excess base (NaBH4 + NaOH) from β-elimination reaction and HCl from base neutralization | SPE requires more thorough desalting with H2O prior to elution of glycans | |
• | Poor MALDI-FT-ICR-MS data | |||
• | Sample spots appear normal with good crystal definition | Excess H2O desalting of SPE cartridge prior to elution, or too fast a washing rate | • | Slow desalting rate (~1 ml/min) |
• | Poor MALDI-FT-ICR-MS data | • | Fine-tune volume of desalting wash to sample size |
Note: In the presence of excess HCl, spots appeared normal with good crystal definition and no apparent effects on MALDI-FT-ICR-MS data.