Titratable acidity is an important parameter in determining fruit maturity and sour taste in citrus fruits. The maturity of fruit is one of the most important factors to determine how well fruit will store and how it will taste. For some fruits, governmental quality standards (based on titratable acidity or the ratio of total soluble solids (°Brix) to titratable acidity) are in place to protect consumers. Immature fruit will normally have a low sugar to acid ratio as compared to mature fruit that will have a high sugar to acid ratio.
The HI84532 measures the concentration of titratable hydrogen ions contained in fruit juice samples by neutralization with a strong base solution to a fixed pH. This value includes all the substances of an acidic nature in the fruit juice including: free hydrogen ions, organic acids and acid salts. Titratable acidity is expressed as g/100 mL of the predominant acid. The predominant acids in fruit depend on the type of fruit being tested and include citric acid, tartaric acid, and malic acid.
Double Junction pH Electrode
The HI84532 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 titrations in the beverage industry.
Custom pH Calibration
According to AOAC International the titration endpoint for fruit products is pH 8.1. The HI84532 uses a custom calibration point of pH 8.20. The preprogrammed pH 4.01 and pH 8.20 calibration points allows for calibration of the meter that brackets the pH readings.
Good Laboratory Practice
The HI84532 offers comprehensive GLP information including date and time of the last pH electrode and dosing pump calibrations. Tracking calibrations are critical to have confidence in the results obtained from titrations. The GLP data is stored along with any logged readings.
Piston Driven Dosing Pump
The heart of the HI84532 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. This titrant is dynamically dosed, where titrant is delivered in larger doses at the start of the titration and smaller doses near the end point. With larger doses in the beginning of the titration, the speed of the titration is increased, where smaller doses near the end point allow for more time for the titrant and analyte to react. Smaller doses also prevent the over titration of a sample and a more accurate determination of titrant volume used.
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 InterfaceThe HI84532 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.
The HI84532 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 HI84532 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 Checkfunction not only ensures an accurate pH reading when the HI84532 is used as a pH meter, but also an accurate titration since the endpoint of a titratable acidity titration is determined by a set pH value.