AQUALAB TDL 2:
Measure the unmeasurable
Make precision USP 922-compliant measurements in minutes, even on highly volatile samples.

Water activity instruments come in all shapes, sizes, and sensors. But none could accurately or reliably measure the highly volatile compounds often used in the pharma industry. Until now.

The volatile problem, solved
Volatiles have long complicated aw (RH) measurements. During readings, volatilized molecules would mix with water vapor and confuse, damage, or delay sensors. At a certain volatile threshold, reliably measuring water activity was simply impossible. For years, time-consuming theoretical calculations were the only way to make progress.
The new TDL 2 does what other sensors can’t: completely ignore deceptive volatile compounds.
The math vs. the measurements
The TDL unlocks a vast new landscape of previously impossible direct measurements – this graph is just a glimpse. With every substance we’ve tested, the TDL matches theoretical values – and in some cases, sent scientists scrambling to correct shaky calculations.


Stop fussing with filters
No matter the compound or concentration, only water’s unique isotopic wavelength signature can trigger the TDL’s sensor. Whatever the volatile – from isopropanol to acetonitrile – it will have no effect on the TDL’s accuracy or measurement speed.
Molecular precision
Read any volatile
<5 min readings
No filters
Laser precision. Literally.
The TDL owes its accuracy to a powerful laser. Less than one nanometer wide, the laser is tuned to water’s signature on a molecular level. Direct interaction between laser, sensor and water vapor makes risky theoretical calculations completely unnecessary.

The TDL plays key roles at some of the world’s top pharmaceutical companies.
- Final product release testing
- Establishing skip-lot testing suitability
- API stability studies
- Setting packaging and storage standards
- Microbial limits testing

Accurate to ±0.005. In five minutes or less.
Most instruments need 30-60 minutes for a single reading – if they can handle volatiles at all. The TDL delivers dozens of readings in the time it takes to find and install the right filter on an electrolytic sensor.
Features summary
- Accurate to ±0.005 aw
- Read any sample, even highly volatile compounds, with no filters or fuss
- Quick: readings in five minutes or less
- Verifiable with independent salt standards
- Easy to use: precise water activity readings with minimal training
- Low maintenance: no moving parts to wear out
- Secure: offers administrative control over calibration and data
- Repeatable: different users, different locations, same result
- Portable: weighs just 7 pounds
Technical specifications
Measurement Specifications
Water Activity
- Range: 0.000–1.000 aw
- Resolution: 0.0001 aw
- Accuracy: ±0.005 aw @ 25 ◦C
Temperature
- Range: 15–50 °C
- Resolution: 0.01 °C
- Accuracy: ± 0.1 °C
- Adjustment increment: 1 °C
Read Time
- ~5 min
Operating environment
- 0% - 90% noncondensing
Operating temperature
- Minimum: 4 °C
- Typical: 23 °C
- Maximum: 50 °C

Let’s talk applications.
You don’t have to figure out how a new instrument fits into your workflow alone. We’re eager to hear your goals and discuss how we can help. Submit this form to talk to an expert.
Masters of moisture.
From cleansing irradiated Fukushima rice paddies to contributing to the discovery of moisture on Mars, we've solved complex problems in a long list of industries. More about METER →
