HI5421-02 | Professional Benchtop Dissolved Oxygen & BOD Meter

R 25,017.00 *

Prices excluded VAT and delivery costs

Delivery time approx. 2 to 4 weeks

  • HI5421-02
HI-5421 has a large, graphic LCD, backlit for improved clarity and a user-friendly soft touch... more
Product information "HI5421-02 | Professional Benchtop Dissolved Oxygen & BOD Meter"

HI-5421 has a large, graphic LCD, backlit for improved clarity and a user-friendly soft touch keypad.

This is a highly advanced instrument featuring an intuitive menu system to streamline the workflow process and provide accurate measurements quickly and efficiently.

DO measurements can be performed in ppm (mg/L) range or in % and feature automatic or manual temperature and atmospheric pressure compensation and manual salinity compensation.

Automatic and manual calibration of dissolved oxygen can be performed in one or two points using standard or user-defined standards.

Users can set the reading stability criteria choosing from three modes: Fast; Medium; or Accurate. When measurement stability is reached, the direct/autohold feature automatically holds the reading on the display. In direct reading mode, the user interface can be set to basic with or without GLP, graphic or logging information.


Key features

  • Extended DO range up to 90ppm (mg/L) and 600%
  • Three salinity scales: practical salinity, natural sea water, percent
  • Measures DO, atmospheric pressure & temperature
  • DO direct, DO direct/autohold, BOD: Biological Oxygen Demand, OUR: Oxygen Uptake Rate, SOUR: Specific Oxygen Uptake Rate
  • Temperature and atmospheric pressure automatic compensation
  • Manual salinity compensation
  • Large log memory with different logging methods
  • Polarographic probe with built-in temperature sensor
  • Improved backlit display
  • Capacitive touch key pad
  • Clean user interface
  • On-screen help


Advanced measurement

The HI-5421 can be used to perform a full range of DO, BOD, OUR and SOUR measurements together with atmospheric pressure and temperature.

The DO probe uses the polarographic principal of measurement and has a built-in temperature sensor. The BOD, OUR and SOUR methods are supported with a dedicated tutorial and step by step guide to ensure a full and correct reading of DO using this specific measuring method.


Up to 10 profiles can be saved and recalled eliminating the need to reconfigure each time a different electrode is used. User definable configurations can include:

Reading mode

  • direct or BOD, OUR and SOUR measurement units
  • temperature units
  • stability criteria




  • temperature
  • atmospheric pressure
  • salinity


Three selectable logging modes are available: Automatic, Manual and AutoHold logging. Up to 100 logging lots can be stored for automatic or manual modes. Automatic logging also features a selectable area and sampling period.

GLP informatics includes complete data about user calibration of each parameter and identification information for the instrument, user and company.

Data can be transferred to a PC via the opto-isolated PC interface via the RS232 or USB ports and HI-92000 Windows compatible software.

All features are available in English, Italian, Portuguese and Spanish. Contextual help is available through a dedicated HELP key with clear tutorial messages and directions available on-screen. This guides users quickly and clearly through the procedures to facilitate accurate measurement and calibration.


Supplied with

  • HI-76483 DO probe
  • HI-76404N electrode holder
  • HI-7041S electrolyte solution (30mL)
  • DO membrane caps (2)
  • 12 VDC adapter
  • Quality certificate
  • Instruction manual


The HI5421 is an advanced research grade benchtop dissolved oxygen and BOD meter that is completely customizable with a large color LCD, capacitive touch keys, and USB port for computer connectivity.

The HI5421 is supplied with the HI76483 Clark-Type Polarographic probe that measures a wide range of dissolved oxygen from 0.0 to 600% saturation and 0.00 to 90.00 mg/L (ppm). The HI76483 is only 12 mm in diameter and has a built-in thermistor temperature sensor that compensates for temperature variations from 0 to 50 oC.

The HI5421 can be calibrated automatically to two points (0% and 100% saturation or 0.00 mg/L and 8.26 mg/L) or to a user-defined value. The calibration data including date, time, and calibration points can be accessed at any time along with the current measurement by selecting the Good Laboratory Practice (GLP) display option.

Readings are compensated for barometric pressure by a built-in pressure transducer located in the meter. Calibration of the barometric pressure is a single point with manual entry of current value obtained from local weather service or other device. Barometric pressure is displayed in a multiple choice of units including mmHg, mbar, kPa, mHg, psi, and atm.  The HI5421 also allow for automatic salinity compensation with a selectable salinity range of 0 to 45 g/L.

The HI5421 offers three additional measurement modes: Biological Oxygen Demand (BOD), Oxygen Uptake Rate (OUR) and Specific Oxygen Uptake Rate (SOUR). Simply enter values and take readings at appropriate times and the meter will automatically calculate the values. 

Three selectable logging modes are available: automatic, manual and AutoHold logging. Up to 100,000 data points can be recorded in 100 lots with 50,000 records max/lot and exported to a computer for data review and storage.


Features at-a-glance

Highly Customizable User Interface – The user interface of the HI5421 allows the user to show measurements in various modes: basic measurement with or without GLP information, real-time graphing, and logging data. Calibration stability criteria can be adjusted from fast, moderate, and accurate. Programmable alarm limits can be set to inside or outside allowable limits.

Color Graphic LCD – The HI5421 features a color graphic LCD with on-screen help, graphic, and custom color configurations. The display allows for real-time graphing and the use of virtual keys provide for an intuitive user interface.

Capacitive Touch – The HI5421 features sensitive capacitive touch buttons for accurate keystrokes when navigating menus and screens. There are four dedicated keys that are used for routine operations including calibration and switching measurement modes and four virtual keys that change based upon use. The capacitive touch technology ensures the buttons never get clogged with sample residue. 

Built in Barometer – The HI5421 has a built-in pressure transducer to automatic barometric pressure compensation of all dissolved oxygen measurements. The barometric pressure can be calibrated to a single point. 

BOD, OUR and Sour Measurement Modes – An additional three measurement modes are available to measure Biological Oxygen Demand (BOD), Oxygen Uptake Rate (OUR) and Specific Oxygen Uptake Rate (SOUR). Simply enter values and take readings at appropriate times and the meter will automatically calculate the values.

Choice of Calibration – Automatic standard recognition is available for two points at 0% and 100% saturation or 0 mg/L and 8.26 mg/L.  A user standard option is available for a user defined value.

GLP Data – HI5421 includes a GLP Feature that allows users to view calibration data and calibration expiration information at the touch of a key. Calibration data include date, time, and calibration points.

Data Logging – Three selectable logging modes are available on the HI5421: automatic, manual, and AutoHold logging. Automatic and manual logs up to 100 lots with 50,000 records max/lot, with up to 100,000 total data points. Automatic logging features the option to save data according to sampling period and interval.

Data Transfer – Data can be transferred to a PC with USB cable and HI92000 software (both sold separately). 

Contextual Help – Contextual help is always available through a dedicated “HELP” key. Clear tutorial messages and directions are available on-screen to quickly and easily guide users through setup and calibration.  The help information displayed is relative to the setting/option being viewed.


DO Specifications

DO Range 0.00 to 90.00 ppm (mg/L); 0.0 to 600.0 % saturation
DO Resolution 0.01 ppm (mg/L); 0.1% saturation
DO Accuracy ±1.5% of reading ±1 digit
DO Calibration automatic using single or two-point calibration; user calibration single point
DO Temperature Compensation 0.0 to 50.0 °C; 32.0 to 122.0 °F; 237.1 to 323.1 K
Salinity Compensation 0 to 45 ppt

Barometric Pressure Specifications

Barometric Pressure Range 450 to 850 mmHg; 560 to 1133 mBar (additional units available (kPa, mHg, psi, atm))
Barometric Pressure Resolution 1 mm Hg
Barometric Pressure Accuracy ±3 mm Hg + 1 least significant digit

Temperature Specifications

Temperature Range -20.0 to 120.0 ºC**; -4.0 to 248.0 ºF**; 253.15 to 393.15 K**
Temperature Resolution 0.1 °C, 0.1 °F, 0.1 K
Temperature Accuracy ±0.2 °C; ±0.4 °F; ±0.2 K (without probe)

Additional Specifications

Electrode/Probe HI76483 thin body, polarographic dissolved oxygen probe with internal temperature sensor and 1 m (3.3’) cable (included)
Measurement Modes direct DO; BOD (biochemical oxygen demand); OUR (oxygen uptake rate); SOUR (specific oxygen uptake rate)
GLP calibration data including date, time, and calibration points
Logging record: 100,000 data point storage, 100 lots with 50,000 records/lot; interval: settable between 1 second and 180 minutes max log time; type: automatic, manual, AutoHold
Display color graphic LCD with on-screen help, graphing, and custom color configuration
Connectivity USB
Environment 0 to 50°C (32 to 122°F; 273 to 323 K), RH max 95% non-condensing
Power Supply 12 VDC adapter (included)
Dimensions 160 x 231 x 94 mm (6.3 x 9.1 x 3.7”)
Weight 1.2 kg (2.64 lbs.)
Ordering Information HI5421 is supplied with HI76483 DO probe, HI76404W electrode holder, HI7041S electrolyte solution (30 mL), HI76483A DO membrane caps (2), 12 VDC adapter, instrument quality certificate and instruction manual
Warranty 2 years (probe 6 months)
Notes **Reduced to actual probe limits
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