The VSA is an automatic isotherm generator from the world leaders in water activity measurement. The VSA is the only automatic isotherm generator that can generate isotherms using both the Dynamic Vapor Sorption (DVS) method, which generates equilibrium isotherms, and the Dynamic Dew Point Isotherm (DDI) method, which generates dynamic isotherms. By combining both methods in one instrument, the VSA makes it possible to investigate both dynamic matrix changes due to water sorption and the kinetics of those changes. This manual details VSA operation and provides information on the capabilities of the VSA.

Water Activity

• Range: 0.030–0.95 aw (3%–95% RH)
• Resolution:
  0.0001 aw (0.01% RH)
  ±0.001 aw (0.1% RH) for volatiles setting
• Accuracy: ±0.005 at 25 °C

Temperature

• Range: 15–50 °C
• Resolution: 0.01 °C
• Accuracy: ±0.1 °C
• Adjustment Increment: 1 °C

Read Time

• ~5 min

Isotherm Methods

• Dynamic Dew Point Isotherm (DDI) and Static (DVS)

External Gas

• 7 psi max

Mass Resolution

• 0.5 mg