Thermo Fisher, NP0007, NuPAGE™ LDS Sample Buffer (4X), 10mL

NuPAGE™ LDS Sample Buffer is a 4X concentrated sample-loading buffer for preparing proteins for denaturing electrophoresis on NuPAGE Bis-Tris or Tris-Acetate gels. This 10 mL formulation contains lithium dodecyl sulfate, Tris buffer, glycerol, EDTA, SERVA Blue G250, and phenol red at approximately pH 8.5. LDS denatures proteins while glycerol increases sample density for loading. The tracking dyes provide a visible migration front without relying on bromophenol blue, helping retain very small peptides during MES-based separations. For standard use, the buffer is diluted to 1X in the final sample mixture, with a reducing agent added when reduced electrophoresis is required. Heating at approximately 70 °C for 10 minutes is commonly used for NuPAGE sample preparation. Store the concentrated buffer at 4–25 °C.