How much is there.
Mass on the crystal lowers its resonance. On a 5 MHz crystal one hertz is 17.7 ng/cm² of rigid film (Sauerbrey).
Benchtop instrumentsopenQCM NEXTQCM-D on every overtone, chamber held at ±0.01 °CopenQCM Q-1QCM-D on one selected overtone at a timeopenQCM Wi2Frequency QCM, USB-powered and wireless-ready
openQCM NEXT · Multi-harmonic QCM-DNEXT, unfolded.
Multi-overtone QCM-D with active thermal control.Frequency and dissipation on five overtones, from the 1st to the 9th, in a ~50 µl cell held to ±0.01 °C. Open hardware, open firmware, open software.
- Overtones
- n = 1 … 9
- 5 MHz crystals · n ≤ 5 at 10 MHz
- Full cycle
- ~9 s
- all overtones, every cycle
- Frequency noise, air
- 0.2–0.8 Hz
- SD of Δfₙ/n, n = 1 … 9, 5 min · 1 Hz readout step
- Temperature
- ±0.01 °C
- set point 25–45 °C, Peltier
- Cell volume
- ~50 µl
- PTFE core, FKM O-ring
- Size · weight
- 20 × 8 × 4 cm
- ~260 g · USB
Illustration / not to scale
One instrument. More perspectives.
Start with the whole instrument, then open the view. NEXT brings frequency, dissipation and active thermal control into the same experimental architecture.
Full specifications
Crystal, acquisition and thermal specifications, in one reference.
Three readings of one surface.
Every cycle NEXT reads the frequency and the dissipation of each overtone. Together they tell how much is on the crystal, how soft it is and how deep it goes.
How soft it is.
A soft, hydrated layer damps the oscillation and widens the resonance. Dissipation tells a rigid film from a gel.
How deep it goes.
Each overtone probes a thinner slice above the crystal. When the overtones disagree, the layer is not rigid: that is where modelling starts.
Air, water, isopropanol. Five overtones at once.
Measured data, not an illustration: one crystal, one continuous run of 75 minutes, every reading of all five overtones as the instrument logged it.
Show
Overtones
Point at the chart.
Each line is one overtone: its frequency shift divided by n, so that a rigid mass would put them all on one curve. In a liquid they fan out, because the liquid each overtone feels gets thinner as n grows.
The Kanazawa check
The physics, read back from the data.
For a crystal in a Newtonian liquid the frequency drops in proportion to √(ρη). Isopropanol should therefore shift 1.34× as much as water on every overtone, whatever the electrode. Measured, overtone by overtone:
| n | Δf/n, water | Δf/n, isopropanol | Ratio, measured | Kanazawa Δf/n, water, 25 °C | ΔΓ/n, water | Kanazawa ΔΓ/n |
|---|
Beyond QCM-D.
The same bridge, extended: electrochemistry, optical access and pipetting, each as a module that clips onto the instrument.
EQCM module
Still an experimental prototype. A combined QCM + EC cell: the quartz sensor is at once the resonator and the working electrode, so mass and charge transfer are read at the same surface, in real time, with your potentiostat.
Open the EQCM module page
Optical fluidic module
A fluidic module with a Ø 7 mm fused-silica window embedded in the PTFE core: watch the chamber, or run spectroscopy or Raman alongside QCM, with the same thermal bridge underneath.
Read about the optical module
Tilting for pipetting
An open PTFE cover gives direct access to the crystal: tilt the heatsink to horizontal, pipette a small volume onto the sensor and measure, with a small lid against evaporation and contamination.
Read about the pipetting moduleThe spec sheet.
As published on openqcm.com. Anything not listed is open in the firmware and the source code.
Measurement
- Frequency std. deviation, air
- 0.2–0.8 HzΔfₙ/n, 1st–9th, 5 min, measured 11 Sept 2026 · readout step 1 Hz on Δfₙ · 9th marked beta
- Frequency std. deviation, liquid
- 0.3–1.5 HzΔfₙ/n in water, 1st–9th, 5 min, measured 11 Sept 2026 · 9th marked beta
- Dissipation std. deviation, air
- 0.02–0.07 ppm5 min, measured 11 Sept 2026
- Dissipation std. deviation, liquid
- 0.05–0.36 ppmwater, 5 min, 25 °C · measured 11 Sept 2026, the run below
- Mass sensitivity
- 1.767 × 10⁻⁸ g Hz⁻¹ cm⁻²5 MHz crystal
Crystal & overtones
- Crystals
- 5 MHz · 10 MHzAT-cut, Ø 14 mm blank
- Frequency range
- 1–50 MHz
- Overtones
- up to n = 9 · up to n = 55 MHz · 10 MHz crystal
- Frequency synthesis
- AD9851 DDScalibration sweep 1–51 MHz
- Readout
- gain and phaseAD8302, network-analyzer sweep
Thermal control
- Range
- 25–45 °CPeltier, closed loop
- Set-point stability
- ±0.01 °C
- Controller
- Thorlabs MTD415T10 kΩ thermistor in the fluidic module
Fluidics
- Fluidic module volume
- ~50 µl
- Channel
- engraved in the PTFE corefluid thermalization
- Wetted materials
- PTFE · FKM (Viton) O-ringplus the crystal's Ti/Au electrode
- Variants
- standard · optical windowsilica glass window
Electronics & connection
- Microcontroller
- Teensy 4.0ARM Cortex-M7
- Connection
- USBserial COM port
- Power
- 5 VDC USB + 5 VDC Peltier5 V / 2.1 A adaptor included
- Firmware
- open, Arduino-basedTeensy
Mechanical
- Dimensions
- 200 × 80 × 40 mm
- Weight
- ~260 g
- Body
- chrome-plated aluminium heatsinkthermal bridge with PTFE slot
Software
- Application
- openQCM NEXT · Python
- Platforms
- Windows 64-bit executable · Python sourcemacOS and Linux from source
- Licence
- CC BY-NC-SA 4.0
Open firmware, open software.
A Python application for Windows, macOS and Linux, Teensy firmware, and the user guide. Everything is downloadable; the source lives on GitHub.
Software
Documents
Open source & community
Release notes by email
Know when a new version is out.
New openQCM software and firmware releases, with what changed, plus the occasional application note. A few emails a year.
NEXT, in the papers.
Recent publications where openQCM NEXT was the measuring instrument, from the openQCM bibliography.
A functional metal-organic framework for dual gas sensing (CH4/CO2) using a quartz crystal microbalance
J. S. Malhotra, M. Kubus, K. S. Pedersen, S. I. Andersen, J. Sundberg
Read the publicationSynthesis and Characterization of a Nanoscale Hyaluronic Acid-Specific Probe for Magnetic Particle Imaging and Magnetic Resonance Imaging
Harald Kratz, Dietmar Eberbeck, Frank Wiekhorst, Matthias Taupitz, Jörg Schnorr
Read at the publisherA biofilm-derived peptide as an underwater adhesive
Xin Huang, Ewelina D. Liszczyk, Ramesh Prasad, Megan E. Mitchell, Zhijie Wang, Yuchu Liu, Sarvagya Saluja, Mingyu Wang, Rebekah A. Jackson, Peter Dahl, Roberto C. Andresen Eguiluz, Nikhil Malvankar, Elsa C. Y. Yan, Rich Olson, Huan‐Xiang Zhou, Jing Yan
Read at the publisher08 / Talk with us
See NEXT in your lab.
We build and ship from Pompeii, Italy. Tell us the measurement you have in mind and we will tell you which configuration, modules and crystals fit it.
openQCM NEXT (R&D kit): €4,499 excl. VAT, on the store