MicroCal PEAQ-DSC Automated

The MicroCal PEAQ-DSC is also available as a manual system without the autosampler.

How It Works

Functional structures created using proteins and other macromolecules frequently undergo temperature-induced conformational changes, such as unfolding. These changes cause heat absorption as a result of the redistribution of non-covalent bonds within the molecule. Differential Scanning Calorimeters calculate this heat uptake highly precisely.

The thermal core of the MicroCal PEAQ-DSC Automated system has a reference cell (containing a matched buffer solution) and a sample cell (containing the sample of interest), both of which are placed within an insulating jacket. These two cells are constantly maintained at the same temperature, and while performing a measurement, they are heated at a constant scan rate.

When the molecule within the sample cell unfolds, heat is absorbed, creating a temperature difference (ΔT) between the reference cell and the sample cell. This results in a thermal gradient across the Peltier units, generating a proportional voltage, which is converted to power to form a feedback loop to the Peltier units, in order to return ΔT to zero.

As protein unfolding is an endothermic event, it is seen as a positive displacement in the thermogram. This protein ‘melting’ transition’s midpoint is the T_M, and the area under the curve is the enthalpy (ΔH) of the unfolding process (see image below).

Specifications

General

Technology: Differential Scanning Calorimetry

Measurement type: Temperature midpoint (T_M); Enthalpy (ΔH); Heat capacity change (ΔC_p)

Cell

Cell: Capillary

Cell material: Tantalum

Cell volume: 130 µL

Sample

Sample capacity: 288 (6 × 96-well plates)

Sample volume: 325 µL

Typical sample concentration: 0.01 mg/mL – 10 mg/mL ¹

Sample throughput: ≤50 samples/day

Sample storage temperature range: 4 °C – 40 °C

System

Noise: 0.05 µCal/°C ²

Baseline repeatability: 1 µCal/°C ²

Response time: 5s ²

Repeatability: <0.2 µCal/°C ³

Reproducibility: <0.08 °C St. Dev. T_M and <2% RSD on ΔH ⁴

System reproducibility: <0.1°C St. Dev. T_M and <5% RSD on ΔH ⁴

Multiple feedback modes: Yes (passive, high gain and low gain)

Temperature range: 2 °C to 130 °C ^{2, 5}

Maximum scan rate: 240 °C/h

Reverse scanning: Yes

Pressure perturbation calorimetry (PPC): N/A

Cleaning solvents: Water and detergent used as standard

Cleaning routines: Three pre-programmed routines

Software

21 CFR part 11: Yes, with PEAQ-Compliance software option

Network ready: Yes, with email alert capability

Operating Environment

Operating temperature (°C): +10 °C to +28 °C

Storage temperature: -20 °C to +50 °C

Humidity: 10% to 70%, non-condensing (10% to 90% for storage)

Ingress Protection (IP) rating: IP21

Power: 100-240 V A/C, 50/60 Hz, 70 W (cell), 400 W (max, autosampler), PC as supplied

Certification: CE (EN61010-1), EN61326-1, FCC, ICES, VCCI), EMC (EN61326-2-1, ISO9001:2008

Weight and Dimensions

Dimensions (W, D, H): 101 cm × 68 cm × 70 cm

Weight: Approx. 25 kg

Notes

¹ Sample dependent² Typical results for ribonuclease (RNase) in 50 mM KAc buffer at pH 5.5, at 60 °C/h with passive feedback³ Rescans of a stable buffer⁴ Using ribonuclease (RNase)⁵ Range may be extended down to -10 °C upon request