# US 12,601,705 B2 · Sensor for measuring ionized magnesium

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- Number: US 12,601,705 B2
- Document ID: US12601705B2
- Status: Granted
- Kind: B2
- Application number: 18/107,188
- Filed: 2023-02-08
- Published: 2023-09-28
- Granted: 2026-04-14
- Earliest claimed: 2022-02-09
- Assignees: Instrumentation Laboratory Company
- Applicants: Instrumentation Laboratory Company
- Inventors: Anahita Karimi; Sohrab Mansouri
- Web page: https://patentgrep.com/patent/US12601705B2

## CPC

- G01N 27/3335: {the membrane containing at least one organic component (G01N27/3271 takes precedence; aspects concerning the enzyme reagent in enzyme electrodes C12Q1/001)}
- G01N 27/333: Ion-selective electrodes or membranes (glass electrodes G01N27/36)
- G01N 33/84: involving inorganic compounds or pH
- G01N 33/48707: {by electrical means (G01N33/49, G01N33/493 take precedence)}
- G01N 33/49: Blood {(chemical methods for determining blood cell populations G01N33/5094; chemical analysis of blood groups or blood types G01N33/80)}
- G01N 33/4925: {measuring blood gas content, e.g. O2, CO2 , HCO3}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

An example sensor includes a conductive electrode and an ion-selective membrane over the conductive electrode. The ion-selective membrane includes an ionophore that is selective for ionized magnesium (iMg) and at least two types of anionic lipophilic salts. The at least two types of anionic lipophilic salts may include one or more fluorinated borate salts and one or more chlorinated borate salts.

## Claims

### Claim 1

A cartridge comprising:
a sensor comprising:
a conductive electrode; and
an ion-selective membrane over the conductive electrode, the ion-selective membrane comprising:
an ionophore that is selective for ionized magnesium (iMg); and
at least two types of anionic lipophilic salts; and
a reagent comprising a biosurfactant.

### Claim 2 (depends on 1)

The cartridge of claim 1, wherein the ion-selective membrane comprises 1% to 4% weight-by-weight (w/w) of one or more ionophores.

### Claim 3 (depends on 1)

The cartridge of claim 1, wherein the one or more ionophores comprise:
ETH 5506 where ETH 5506 is C63H96N6O6 (1,3,5-Tris[10-(1-adamantyl)-7,9-dioxo-6,10-diazaundecyl]benzene); or
ETH 7025, where ETH 7025 is C49H94N6O6 (N,N′,N″-Tris[3-(heptylmethylamino)-3-oxopropionyl]-8,8′-iminodioctylamine); or
K22B5, where K22B5 is C38H60N4O8 (4,13-[Bis(N-adamantylcarbamoyl)acetyl]-1,7,10,16,tetraoxa-4,13-diazacyclooctadecane).

### Claim 4 (depends on 1)

The cartridge of claim 1, wherein the biosurfactant comprises at least one of a high molecular weight biosurfactant or a low molecular weight biosurfactant.

### Claim 5 (depends on 4)

The cartridge of claim 4, wherein the low molecular weight biosurfactant comprises at least one of a rhamnolipid, a sophorolipid, or a lipopeptide; and
wherein the high molecular weight biosurfactant comprises at least one of a polysaccharide, a lipopolysaccharide, a protein, or a lipoprotein.

### Claim 6 (depends on 1)

The cartridge of claim 1, wherein the sensor comprises a sample path adjacent to the ion-selective membrane; and
wherein the cartridge comprises a fluid path that runs at least from at least one of a location at which a test sample is introduced into the cartridge or a location of the reagent to the sample path.

### Claim 7 (depends on 1)

A system comprising:
a test instrument to receive the cartridge of claim 1;
wherein the sensor comprises a conductive electrode having an electrical potential that is based on an activity of iMg in a test sample;
an electrical contact to measure the electrical potential; and
one or more processing devices to determine an amount of iMg in the test sample based on the electrical potential.

### Claim 8 (depends on 7)

The system of claim 7, wherein the system comprises a point-of-care clinical analyzer system.

### Claim 9 (depends on 1)

The cartridge of claim 1, wherein:
the ion-selective membrane further comprises a plasticizer, and
the at least two types of anionic lipophilic salts comprise a mixture of one or more chlorinated borate salts and one or more fluorinated borate salts.

### Claim 10 (depends on 9)

The cartridge of claim 9, wherein the at least two types of anionic lipophilic salts are present in the ion-selective membrane at a ratio of 1:1.

### Claim 11 (depends on 9)

The cartridge of claim 9, wherein the at least two types of anionic lipophilic salts are present in the ion-selective membrane at a ratio of between 1.5:1 and 2.1:1.

### Claim 12 (depends on 9)

The cartridge of claim 9, wherein the ion-selective membrane comprises 1% to 3% weight-by-weight (w/w) of the mixture of one or more chlorinated borate salts and one or more fluorinated borate salts.

### Claim 13 (depends on 9)

The cartridge of claim 9, wherein the one or more chlorinated borate salts comprises at least one of: potassium tetrakis(4-chlorophenyl)borate (KTpClPB) or sodium tetrakis(4-chlorophenyl)borate); and
wherein the one or more fluorinated borate salts comprises at least one of: tetrakis(4-fluorophenyl)boron sodium (Cesibor), sodium or potassium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaTPB or KTFPB), or sodium or potassium tetrakis[3,5-bis(1,1,1,3,3,3-hexafluoro-2-methoxy-2-propyl)phenyl]borate trihydrate (HFPB).

### Claim 14 (depends on 9)

The cartridge of claim 9, wherein the ion selective membrane comprises an outer membrane and a plasticizer comprising a majority of the outer membrane.

### Claim 15 (depends on 9)

The cartridge of claim 9, wherein the plasticizer has a log P (partition coefficient) value of between 6.7 and 8.9.

### Claim 16 (depends on 9)

The cartridge of claim 9, wherein the ion-selective membrane comprises 60% to 66% weight-by-weight (w/w) of the plasticizer.

### Claim 17 (depends on 9)

The cartridge of claim 9, wherein the plasticizer comprises:
ETH 8045 where ETH 8045 is C26H37NO3 ([12-(4-Ethylphenyl)dodecyl]2-nitrophenyl ether); or
a mixture comprising ETH 8045 and NPOE, where NPOE is C14H21NO3 (1-(2-Nitrophenoxy)octane); or
a mixture comprising ETH 8045 and ETH 217, where ETH 217 is C18H29NO3 (1-Dodecyloxy-2-nitrobenzene, 2-Nitrophenyl dodecyl ether); or
a mixture comprising ETH 8045, ETH 217, and NPOE.

### Claim 18 (depends on 9)

The cartridge of claim 9, wherein the ion-selective membrane comprises:
an inner membrane comprising a hydrogel; and
an outer membrane comprising the ionophore, the at least two types of anionic lipophilic salts, the plasticizer, and a polymeric matrix.

### Claim 19 (depends on 9)

The cartridge of claim 9, wherein the sensor has a consistent amount of iMg selectivity and a consistent Nernstian response for at least 30 days.

### Claim 20 (depends on 1)

The cartridge of claim 1, wherein the at least two types of anionic lipophilic salts comprise at least one of: potassium tetrakis(4-chlorophenyl)borate (KTpClPB) or sodium tetrakis(4-chlorophenyl)borate); and
at least one of: sodium or potassium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaTPB or KTFPB).