Using Hydrofluoric Acid or Ammonium Bifluoride to clean NMR tubes

Some NMR tube cleaning procedures have called for the use of HF and/or (NH4)2F2 before final rinsing with DI water and drying. Since glass is solubilized with these reagents, the NMR tube walls become thinner and also irregular with time, since the dissolution rate is uneven and unpredictable on the wall's surface. Not only will the NMR tube become compromised in its ability to hold sample without breakage, but the quality of the NMR spectrum will become degraded, because of the irregularity of the wall thickness. Our recommendation is to use a high quality glass cleaning surfactant, such as NRS-250, that removes organic contaminants without damage to the glass walls of the NMR tube and extends the life of the NMR tube.