pH electrodes features

Select features that meet the needs of your applications

The Thermo Scientific electrodes portfolio spans a vast range of industries and applications, and are categorized into digestible classifications to help you choose which electrode is best for your application.

The accuracy of your pH measurements depends on the instrumentation you use. Our extensive assortment of quality pH electrode, sensors, and probes are designed to make your complex measurements routine, reliable, and accurate—in the lab or in the field. They are available in a variety of body materials, body styles, and sample requirements.

Browse pH electrodes by features

The types of available electrodes, the desired electrode features, and the compatibility of the electrode with the sample are all determining factors in selecting the right pH electrode. The following section provides the information needed to select the best pH electrode for your applications. The pH electrodes are available with a glass or epoxy body and a variety of electrode body styles, fill types, references, junctions, and connectors that suit your application. To learn more, see our pH electrodes separated by category and application below.

pH electrode styles

Standard size
standard tip pH electrodes
  • 12 mm electrode diameter for use in a wide variety of sample sizes
  • Accurate, chemically compatible, and fast response are all characteristics of the standard-sized glass bulbs
  • A variety of junctions available from Sure-flow to low-maintenance junctions
Semi-micro
ssemi-micro tip style pH electrodes
  • 6 to 8 mm electrode diameter for sample sizes down to 200 μL
  • Glass body semi-micro electrodes provide superior chemical resistance and can withstand high temperatures while allowing samples down to 200 μL
  • Variety of options to choose from, including epoxy body and glass micro-tip

pH micro and semi-micro electrodes ›

Micro
micro tip style pH electrodes
  • 1 to 5 mm electrode diameter for samples as small as 0.5 μL and containers as small as 384 well plates
  • Microelectrodes are designed to measure small volumes down to 0.5 μL 
  • These delicate electrodes permit insertion into small devices, such as 384 microwell plates
  • A variety of styles available, such as ROSS and septa-piercing tips

pH micro and semi-micro electrodes ›

Rugged bulb
rugged bulb style electrodes
  • When glass is required, the extra durable pH bulb prevents breakage
  • When durability and glass are needed, this bulb design provides all the chemical compatibility of glass electrodes with the added benefit of improved ruggedness
Spear tip
flat spear tip style pH electrodes
  • For piercing solid or semi-solid samples and measuring small-volume samples
  • Spear tip pH electrodes can be used for piercing soft samples like cheese or fruit, or cutting through tougher samples such as meat 
  • For the toughest piercing samples, look for the KnipHe electrode.

pH spear tip style electrodes ›

Flat surface tip
flat spear tip style pH electrodes
  • For measuring a solid surface or gel sample
  • Flat surface electrodes are epoxy body electrodes with a flat pH bulb that allows you to measure moist solid samples or small volumes
  • They can be used on samples such as meats, cheese, or in agar gel plates; available in single- or double-junction designs; either refillable or low-maintenance

pH flat surface tip style electrodes ›

pH electrode junctions

Sure-flow, sleeve, and laser-drilled hole (open)
  • Best junction for dirty, difficult samples
  • Junction is clog-free and easy to clean
  • Ideal for thick or viscous samples, compatible with all sample types
Ceramic and glass capillary
  • Better junction for routine lab or field use
  • Junction is high quality and durable
  • Ideal for most applications and samples
Wick and glass fiber
  • Good junction for routine lab or field use
  • Junction used with rugged epoxy electrodes
  • Ideal for aqueous samples

pH electrode references

ROSS reference
  • 0.01 pH precision
  • Best measurement response time
  • Ideal for virtually any sample type including TRIS, protein, and sulfide samples
  • Variety of body styles and types
  • Refillable or gel design
  • Best temperature response
Double junction Ag/AgCl reference
  • 0.02 pH precision
  • Better measurement response time
  • Ideal for TRIS, protein, and sulfide samples
  • Variety of body styles and types
  • Refillable, polymer or gel design
  • Good temperature response
Single junction Ag/AgCl reference
  • 0.02 to 0.1 pH precision
  • Good measurement response time
  • General purpose for everyday use
  • Variety of body styles and types
  • Refillable or gel design
  • Good temperature response

pH electrode fill types

Refillable
  • Easy maintenance, filling solution required
  • Periodic filling and draining needed
  • Long expected life span
  • 0.01 to 0.02 pH precision
  • Best response time
  • 1 to 2 year warranty (6 months for Ag/AgCl micro electrodes)

pH Refillable Glass Electrodes ›
pH Refillable Epoxy Electrodes ›

Polymer filled (sealed)
  • Low maintenance, no filling solution needed
  • Sealed reference
  • Easy to use, ideal for most applications
  • 0.02 pH precision
  • Better response time
  • 1 year warranty
Gel filled (sealed)
  • Low maintenance, no filling solution needed
  • Sealed reference
  • Easy to use, general purpose
  • +/- 0.02 to 0.1 pH
  • Good response time
  • 3 to 6 month warranty

pH electrode body materials

Glass body
  • Compatible with virtually any sample, including solvents
  • Easy to clean
Epoxy body
  • Extremely durable and rugged to prevent breakage
  • Protective bulb guards
  • Choice of performance

pH electrode connectors

Waterproof BNC

Compatible with any pH meter that has a BNC input; ensures a waterproof and secure connection with the Thermo Scientific Orion Star A series meters

BNC

Compatible with any pH meter that has a BNC input

Screw cap
  • Electrode can be connected to a variety of meter inputs using a separate cable
  • Multiple adapters available as needed
Pin tip

Compatible with meters that have a reference half-cell input

ATC probe connectors

MiniDIN

Compatible with Thermo Scientific pH meters that have an 8-pin MiniDIN ATC input

8-pin DIN

Compatible with the Thermo Scientific Orion Star A meters and pH meters that have an 8-pin DIN ATC input

RCA

Compatible with Mettler Toledo™ pH meters that have an RCA input

ATC probe ordering information

Cat. No. Description
927005MD Epoxy ATC probe, MiniDIN
927006MD Glass ATC probe, MiniDIN
927007MD Stainless steel ATC probe, MiniDIN
928007MD Micro ATC probe with stainless steel 1 mm x 38 mm tip, MiniDIN
917005 Epoxy ATC probe, 8 Pin DIN
917007 Stainless steel ATC probe, 8-pin DIN
927005 Epoxy ATC probe, 3.5 mm phono tip

pH electrode styles

Standard size
standard tip pH electrodes
  • 12 mm electrode diameter for use in a wide variety of sample sizes
  • Accurate, chemically compatible, and fast response are all characteristics of the standard-sized glass bulbs
  • A variety of junctions available from Sure-flow to low-maintenance junctions
Semi-micro
ssemi-micro tip style pH electrodes
  • 6 to 8 mm electrode diameter for sample sizes down to 200 μL
  • Glass body semi-micro electrodes provide superior chemical resistance and can withstand high temperatures while allowing samples down to 200 μL
  • Variety of options to choose from, including epoxy body and glass micro-tip

pH micro and semi-micro electrodes ›

Micro
micro tip style pH electrodes
  • 1 to 5 mm electrode diameter for samples as small as 0.5 μL and containers as small as 384 well plates
  • Microelectrodes are designed to measure small volumes down to 0.5 μL 
  • These delicate electrodes permit insertion into small devices, such as 384 microwell plates
  • A variety of styles available, such as ROSS and septa-piercing tips

pH micro and semi-micro electrodes ›

Rugged bulb
rugged bulb style electrodes
  • When glass is required, the extra durable pH bulb prevents breakage
  • When durability and glass are needed, this bulb design provides all the chemical compatibility of glass electrodes with the added benefit of improved ruggedness
Spear tip
flat spear tip style pH electrodes
  • For piercing solid or semi-solid samples and measuring small-volume samples
  • Spear tip pH electrodes can be used for piercing soft samples like cheese or fruit, or cutting through tougher samples such as meat 
  • For the toughest piercing samples, look for the KnipHe electrode.

pH spear tip style electrodes ›

Flat surface tip
flat spear tip style pH electrodes
  • For measuring a solid surface or gel sample
  • Flat surface electrodes are epoxy body electrodes with a flat pH bulb that allows you to measure moist solid samples or small volumes
  • They can be used on samples such as meats, cheese, or in agar gel plates; available in single- or double-junction designs; either refillable or low-maintenance

pH flat surface tip style electrodes ›

pH electrode junctions

Sure-flow, sleeve, and laser-drilled hole (open)
  • Best junction for dirty, difficult samples
  • Junction is clog-free and easy to clean
  • Ideal for thick or viscous samples, compatible with all sample types
Ceramic and glass capillary
  • Better junction for routine lab or field use
  • Junction is high quality and durable
  • Ideal for most applications and samples
Wick and glass fiber
  • Good junction for routine lab or field use
  • Junction used with rugged epoxy electrodes
  • Ideal for aqueous samples

pH electrode references

ROSS reference
  • 0.01 pH precision
  • Best measurement response time
  • Ideal for virtually any sample type including TRIS, protein, and sulfide samples
  • Variety of body styles and types
  • Refillable or gel design
  • Best temperature response
Double junction Ag/AgCl reference
  • 0.02 pH precision
  • Better measurement response time
  • Ideal for TRIS, protein, and sulfide samples
  • Variety of body styles and types
  • Refillable, polymer or gel design
  • Good temperature response
Single junction Ag/AgCl reference
  • 0.02 to 0.1 pH precision
  • Good measurement response time
  • General purpose for everyday use
  • Variety of body styles and types
  • Refillable or gel design
  • Good temperature response

pH electrode fill types

Refillable
  • Easy maintenance, filling solution required
  • Periodic filling and draining needed
  • Long expected life span
  • 0.01 to 0.02 pH precision
  • Best response time
  • 1 to 2 year warranty (6 months for Ag/AgCl micro electrodes)

pH Refillable Glass Electrodes ›
pH Refillable Epoxy Electrodes ›

Polymer filled (sealed)
  • Low maintenance, no filling solution needed
  • Sealed reference
  • Easy to use, ideal for most applications
  • 0.02 pH precision
  • Better response time
  • 1 year warranty
Gel filled (sealed)
  • Low maintenance, no filling solution needed
  • Sealed reference
  • Easy to use, general purpose
  • +/- 0.02 to 0.1 pH
  • Good response time
  • 3 to 6 month warranty

pH electrode body materials

Glass body
  • Compatible with virtually any sample, including solvents
  • Easy to clean
Epoxy body
  • Extremely durable and rugged to prevent breakage
  • Protective bulb guards
  • Choice of performance

pH electrode connectors

Waterproof BNC

Compatible with any pH meter that has a BNC input; ensures a waterproof and secure connection with the Thermo Scientific Orion Star A series meters

BNC

Compatible with any pH meter that has a BNC input

Screw cap
  • Electrode can be connected to a variety of meter inputs using a separate cable
  • Multiple adapters available as needed
Pin tip

Compatible with meters that have a reference half-cell input

ATC probe connectors

MiniDIN

Compatible with Thermo Scientific pH meters that have an 8-pin MiniDIN ATC input

8-pin DIN

Compatible with the Thermo Scientific Orion Star A meters and pH meters that have an 8-pin DIN ATC input

RCA

Compatible with Mettler Toledo™ pH meters that have an RCA input

ATC probe ordering information

Cat. No. Description
927005MD Epoxy ATC probe, MiniDIN
927006MD Glass ATC probe, MiniDIN
927007MD Stainless steel ATC probe, MiniDIN
928007MD Micro ATC probe with stainless steel 1 mm x 38 mm tip, MiniDIN
917005 Epoxy ATC probe, 8 Pin DIN
917007 Stainless steel ATC probe, 8-pin DIN
927005 Epoxy ATC probe, 3.5 mm phono tip

pH electrodes by category

ROSS electrode

ROSS

  • Fast response, accuracy and reproducibility regardless of sample composition; exhibits unmatched response to temperature variations
  • Double junction reference for complex samples such as biological media, foods, pharmaceuticals, TRIS, sulfides, and proteins
  • Available in all body styles
  • ROSS Ultra electrodes have an industry best warranty

Orion Triode electrode

Triode

  • Combination pH electrode with built-in temperature sensor
  • Convenient ability to measure pH and temperature with one electrode
  • BNC connector for pH measurement and alternative connector for temperature measurement
  • Compatible with Thermo Scientific Orion pH meters and other brands

    The temperature connector and temperature element can be unique to meter model.

Orion SureFlow electrode

Sure-Flow

  • Unique, free-flowing liquid-to-liquid junction
  • Easy-to-clean junction avoids clogging
  • Dirty or viscous samples can be easily measured without a clogged junction
  • Compatible with samples containing organic compounds, proteins, heavy metals, and other compounds that react with silver such as bromides, iodides, cyanides, and sulfides
  • Silver chloride sure-flow electrodes can be used on tough samples that do not require a double junction electrode to prevent contact with silver

Featured pH electrodes categories

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Knowledge Base: Certificates of Analysis and SDS for Orion, ROSS, AQUAfast, AquaMate, and AquaSensors products.

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