EP 4 481 364 B1Granted (EP)
Lateral magnetic sustentation — paramagnetic mass-on-solid measurement
Patent family 1 · underpins PMC-1 / EMC-2
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The science
One idea, carried the whole way through. A magnetic field holds the particle in place. As mass lands on it, the field needed to hold it shifts, and the calibration turns that shift into a captured-mass number. That single force balance is what we patented, and what nine peer-reviewed papers check against orthogonal measurements.
The principle
Three forces hold the particle still: magnetic, gravity, buoyancy. When the analyte adsorbs onto the solid, the field needed to keep the particle in position changes. A second-order calibration reads that change as the mass captured on the solid.
Magnetic = gravity − buoyancy, solved for the mass on the solid.
Two published permanent-magnet calibration lines on commercial MOFs.
The calibration holds across liquids — water and ethanol are the published examples. Particle-size-independent endpoint.
Electromagnet ≤2.0 T (reads H); permanent magnet ≤0.6 T (reads displacement).
Intellectual property
Patent family 1 · underpins PMC-1 / EMC-2
Patent family 2 · underpins DC-10000
EP 4 481 364 B1 is granted. EP 4 636 386 A1 is in examination, with the US application in national phase.
The device family
The two paramagnetic cells carry our deepest published evidence. The diamagnetic cell extends the method to almost any material, but only where the sample fits — it asks for more mass and more careful handling.
Permanent-magnet sustentation. The deepest published evidence base — drug capture, alcohol recovery, drug release, CO₂-from-water — sits here.
Paramagnetic readout. At least 15 mg to load. Functional loading and release, not structural porosity.
Electromagnet sustentation (≤2.0 T). Tunable field for harder-to-suspend paramagnetic systems; same force-balance, same calibration in virtually any liquid at ambient temperature and pressure (water and ethanol are the validated examples).
Paramagnetic readout. At least 15 mg to load. Field set per material; particle-size-independent endpoint.
Levitation by repulsion. The any-material route (Patent family 2). Sample-fit gated — handling and mass requirements are stricter (working range 50–200 mg).
Diamagnetic readout, in examination. At least 50 mg to load (50–200 mg). Any-material is a capability, not a per-field result.
Minimum sorbent mass
We need at least 15 mg on the PMC-1 or EMC-2, and at least 50 mg on the DC-10000 (working range 50–200 mg). That is the minimum material to load for an accurate read — a device spec, not an analyte limit of detection. Analyte-level LOD/LOQ is part of our ongoing metrology work and is not yet published, so we do not quote a detection-limit number.
One calibration per material
Because we read the mass change of the solid, we build one calibration curve per material. Send a clean, non-adsorbed (blank) reference of each material alongside the samples to be tested — we draw the calibration line from the blank, then read any analyte off the same line.
We settle the sample plan, blank included, in the feasibility check before any run begins.
The proof, in one experiment
We measure the CO₂ actually held inside the working solid, straight from water — 22.3 wt%, weighed in situ with its chemical form resolved (the full HCO₃⁻ adduct vs physisorbed). The conventional gravimetric method weighs the whole water-plus-particle system from the outside, so it can only infer the solid's share and under-reads it at 17.1 wt%. That +5.2 wt% is what measuring from the outside misses about what the material is really holding.
On the same Cu₆Cr, a dry measurement reads 0.5 wt% CO₂ (0.12 mmol·g⁻¹) against 22.3 wt% wet — the dry method measures the collapsed material.
That +5.2 wt% gap is the CO₂ on the solid the conventional gravimetric method under-reads, because it weighs the system from the outside and never looks inside the material. It is one proof-of-mechanism result on our reference Cu₆Cr SMOF: evidence about measurement accuracy, not a guarantee of capacity in any particular material or application.
Weighed inside the pore, wet, with the chemical form resolved.
Conventional gravimetry weighs the whole system and backs out the solid's share.
CO₂ sitting on the solid that conventional gravimetry never sees.
The evidence base
9 peer-reviewed papers, co-authored by our CTO Rubén Pérez-Aguirre with the UPV/EHU group. We have grouped them by the part of the story each one carries: the method first, then what it has been proven on. Each card tells you what the paper shows, in plain terms. Follow any DOI to read the source.
The method & calibration
Read the mass on the solid directly in the working liquid, one calibration curve per material, on a maintenance-free device.
Sets out the whole method in one place — the force balance, the per-material calibration, and worked examples across alcohols, drugs and CO₂. The reference that ties the evidence base together.
Pérez-Aguirre & Castillo
The first peer-reviewed proof that mass adsorbed on a paramagnetic solid can be read directly in liquid, validated head-to-head against ¹H-NMR on the same runs — and that a dry BET measurement (3.5 m²/g on the sibling Cu₆Cu host) calls a material non-porous while the method reads its live wet capacity.
Pascual-Colino, Pérez-Aguirre, Castillo et al.
A built permanent-magnet rig (no power, cooling or current control) reads sorption off commercial MOFs in water, with lateral displacement linear in adsorbed mass on MIL-101(Cr) and MIL-100(Fe) at R² > 0.998. This is the device behind the granted patent.
Pérez-Aguirre, Castillo et al.
Drug carriers & release
Loading and release of pharma guests on water-stable carriers, weighed on the solid rather than chased through the supernatant.
A sorbent captures anionic drug pollutants (ibuprofen, naproxen) from water, and a single instrument weighs how much it took up from the magnetic detachment field — reading the solid, not the depleted liquid, on a sorbent that releases its load reversibly at room temperature.
Pérez-Aguirre, Castillo, Wuttke et al.
A water-stable Cu₆Cr carrier loads pharma guests and releases them with pseudo-first-order kinetics — the loading-and-release behaviour the method is designed to rank carrier by carrier.
Mena-Gutiérrez et al.
One flexible Cu₇Naph carrier holds two drugs at once: co-loading cisplatin with 5-FU lifts 5-FU capacity to 14.1 wt% and narrows the two release rates toward each other — the case for ranking host and drug-pair combinations on one read.
Mena-Gutiérrez et al.
CO₂ from water
The proof of mechanism: CO₂ captured directly from water and weighed inside the pore, with isotherms and cycling.
Porous-materials screening
The MOF and SMOF families, their structure and magnetism — the materials the readout was built to characterise.
On an off-the-shelf iron MOF, uptake of eight alcohols from dilute water is read straight off the solid — a clean series ordered by molecular size and hydrophobicity that ranks sorbents without a method rebuilt for each alcohol.
Barroso et al.
Four related Cu₇ adeninate frameworks of the same topology, highly insoluble in water — the kind of tunable, water-stable porous family the readout is built to characterise.
Mena-Gutiérrez, Castillo et al.
From method to measurement
A feasibility check confirms the fit before anything else is agreed.