Alkalinity is the ability of water to neutralize acids. Total titratable alkalinity is a measure of primarily three types of alkalinities present in a water sample: hydroxides, carbonates, and bicarbonates. Alkalinity in water can be the result of contributions from common chemicals including carbonates, bicarbonates, hydroxides, phosphates, borate and organic acid salts.
The alkalinity of a water sample indicates its ability to resist pH change. The amount of alkalinity in water is mostly due to the bicarbonate/carbonate present. A low alkalinity level indicates that the water is susceptible to pH changes, while a high alkalinity level indicates that the water will be able to resist pH changes. Alkalinity can also be used to determine the corrosive capacity of water and can provide an estimation of water hardness.
Double Junction pH Electrode
The HI84531 is supplied with the HI1131B refillable, double junction, combination pH electrode. By design, the HI1131B has a spherical tip for use in aqueous or liquid solutions. This versatile electrode provides a wide surface of contact with a sample and is ideal for direct measurements or acid base titrations in the water industry.
Piston Driven Dosing Pump
The heart of the HI84531 is the piston driven burette pump. This type of dosing system uses a motor in which each dose is very precisely controlled and the volume dispensed is accurately determined. The piston driven burette is controlled dynamically so that the volume of titrant being dosed is automatically adjusted based on a voltage response of the previous dose. This type of dosing speeds up the titration process by allowing for more titrant to be dosed at the start of the titration and then very small doses as the endpoint is reached.
The built-in stirrer is automatically maintained at a speed of 600 rpm, regardless of the viscosity of the solution being titrated.
Easy-to-Use Interface The HI84531 has an intuitive user design with clearly defined keys and a large screen that is easy to navigate. The meter has a built-in tutorial mode that, when enabled, will walk the user step by step through the titration process. A dedicated HELP key is always available to allow access to content-specific information during both calibration and titration.
Procedure Warnings Users are warned if there is an error in procedures such as the titration exceeded the maximum volume of titrant.
Graphic Mode This mini titrator displays in-depth data during titration, including a real-time graph of the titration curve.
Log-on-Demand The HI84531 allows for data logging of up to 400 samples: 200 titration results and 200 pH/mV readings. Data can be stored and exported to a USB drive or a PC using the USB connection.
pH/mV Meter In addition to being an automatic titrator, the HI84531 also can be used as a pH/mV meter. As a pH meter, it has many features of a professional grade benchtop including automatic calibration up to three points with four available buffers, a 0.01 pH resolution, accuracy of ±0.01 pH, automatic temperature compensation and comprehensive GLP data.
CAL Check™ Accuracy is always ensured with Hanna’s unique CAL Check feature, which analyzes the response of the electrode during the calibration process. Based on electrode response in the buffer, indicators are displayed on screen to alert the user of potential problems during calibration. These indicators include Buffer Contaminated, Electrode Dirty/Broken, and overall probe condition. The CAL Check function not only ensures an accurate pH reading when the HI84531 is used as a pH meter, but also an accurate titration since the endpoint of a titratable alkalinity titration is determined by a set pH value.
pH Range -2.0 to 16.0 pH; -2.00 to 16.00 pH pH Resolution 0.1 pH / 0.01 pH pH Accuracy ±0.01 pH (@25ºC/77ºF) pH Calibration one, two or three-point calibration; four available buffers (4.01, 7.01, 8.30, 10.01) pH Temperature Compensation manual or automatic pH-mV Range -2000.0 to 2000.0 mV pH-mV Resolution 0.1 mV pH-mV Accuracy ±1.0 mV (@25ºC/77ºF) Temperature Range -20.0 to 120.0°C; -4.0 to 248.0°F; 253.2 to 393.2 K Temperature Resolution 0.1°C; 0.1°F; 0.1K Temperature Accuracy ±0.4°C; ±0.8°F; ±0.4 K (@25ºC/77ºF), without probe error Titration Range Low Range: 30.0 to 400.0 mg/L; 0.6 to 8.0 meq/L
High Range: 300 to 4000 mg/L; 6.0 to 80.0 meq/L
Titration Resolution Low Range: 0.1 mg/L (ppm); 0.1 meq/L; High Range: 1 mg/L (ppm); 0.1 meq/L Titration Accuracy Low Range: ±1 mg/L or 3% of reading, whichever is greater
High Range: ±10 mg/L or 3% of reading, whichever is greater
Titration Method acid-base titration (strong alkalinity/total alkalinity) Titration Principle endpoint titration: 8.30 pH (phenolphthalein) / 4.50 pH (bromcresol green-methyl red) Titration Pump Speed 10 mL/min Titration Stirring Speed 600 rpm Sample Size Low Range: 50 mL; High Range: 50 mL pH Electrode HI1131B glass body, refillable, with BNC connector and 1 m (3.3’) cable (included) Temperature Probe HI7662-T stainless steel temperature probe with 1 m (3.3’) cable (included) Logging Type Log-on-demand Logging Memory up to 400 ( 200 titrations, 200 pH/mV readings) Connectivity 1 USB port for data storage and export to a PC Built-in Magentic Stirrer Built-in magnetic stirrer at 600 rpm Power Supply 12 VDC adapter (included) Environment 0 to 50°C (32 to 122°F); RH max 95% non-condensing Dimensions 235 x 200 x 150 mm (9.2 x 7.9 x 5.9”) Weight 1.9 kg (67.0 oz.) Ordering Information HI84531 is supplied with HI1131B pH electrode, HI7662-M temperature probe, HI84531-50 low range titrant (120 mL), HI84531-51 high range titrant (120 mL), HI84531-55 calibration standard (230 mL), 100 mL beakers (2), dosing pump valve, 5 mL syringe, 2000 µL automatic pipette with two plastic tips, tube set (aspiration tube with titrant bottle cap and dispensing tube with tip), stir bar, power adapter, instruction manual and quality certificate.