Hanna HI84529 Titratable Acidity Mini Titrator for Dairy Analysis

There are two fundamentally different measurements of dairy products: titratable acidity and pH. pH is a measurement of hydrogen ion concentration while titratable acidity is the neutralizing capacity of a dairy product with NaOH.

An increase in acidity can be caused by bacteria formation. Monitoring acidity is a way of determining the quality and freshness of dairy products. Acidity is determined by a pH endpoint titration using sodium hydroxide, and is defined as the consumption necessary to shift the pH value from 6.6 (corresponding to fresh milk) to a pre-determined pH value. While pH 7.0 is the actual point of neutralization, phenolphthalein is commonly employed as a color indicator to determine the endpoint of the reaction. When using phenolphthalein as an indicator a faint pink  color change occurs at pH 8.3. Titratable acidity is expressed in a variety of units based on the titration method performed. Each method varies in sample size and strength of NaOH used for the titration.

% Lactic Acid (%l.a.): is determined by taking a 20 mL or 20 g sample and diluting with twice its volume with deionized or distilled water. The sample is then titrated with 0.1 M sodium hydroxide to a phenolphthalein end point.

Degree Soxhlet Henkel (°SH): is determined by titrating a 50 mL sample with 0.1 M sodium hydroxide to a phenolphthalein end point.

Degree Dornic (°D): is determined by titrating a 100 mL sample with N/9 sodium hydroxide to a phenolphthalein end point.

Degree Thörner: is determined by taking a 10 mL sample and diluting with twice its volume with deionized or distilled water. The sample is then titrated with 0.1 M sodium hydroxide to a phenolphthalein end point

Knowing the relationship between sample weight or volume and strength of titrant it is possible to convert the reading obtained from one method to another. Below is a table with the factors preprogrammed in the HI84529 for converting between various units of measure.

From:

To:

Divide By:

%l.a.

°SH

0.0225

%l.a.

°D

0.0100

%l.a.

°Th

0.0090

Table for converting % lactic acid (%l.a.) to Degree Soxhlet Henkel (°SH), Degree Dornic (°D), and Degree Thorner °Th.

The HI84529 uses methods based on AOAC International and Standard Methods for the Examination of Dairy Products. Both of these methods report titratable acidity as % lactic acid and a conversion factor is used to convert the results to the other available units. The HI84529 can be customized to meet the needs of any dairy analysis lab. Samples can be titrated by weight or volume, diluted or non-diluted (low range only) and titrated to a Źfixed pH endpoint that can be adjusted by the user.  The HI84529 offers three different methods depending on the expected range and the weight of sample used. Select low range 50 to titrate a 50 ml or 50 g undiluted sample. The other titration options are low range 20 and high range 20 to titrate 20 mL or 20 g samples that are diluted twice their volume with deionized or distilled water.

Specifications

Range Low Range: %l.a.: 0.01 to 0.20; °SH: 0.4 to 8.9; °D: 1.0 to 20.0; °Th: 1.1 to 22.2 High Range: %l.a.: 0.1 to 2.0; °SH: 4.4 to 88.9; °D: 10 to 200; °Th: 11.1 to 222.2
Resolution Low Range: %I.a.: 0.01 ; °SH: 0.1; °D: 0.1; °Th: 0.1 High Range: %I.a.: 0.1; °SH: 0.1; °D: 1; °Th: 0.1
Accuracy (@25ºC/77ºF) Low Range: ± 0.01 %l.a. High Range: ± 0.1 %l.a.
Sample Volume LR 20: 20 mL or 20 g LR 50: 50 mL or 50 g HR 20: 20 mL or 20 g
Method acid base titration
Principle endpoint titration, adjustable (pH 8.0 - 8.7 in 0.1 increments)
Pump Speed 10 mL/min
Stirring Speed 800 (Low Range) / 1000 (High Range)
pH Range -2.0 to 16.0 pH; -2.00 to 16.00 pH
pH Resolution 0.1 pH / 0.01 pH
pH Accuracy (@25ºC/77ºF) ±0.01 pH
pH Calibration one, two, or three-point calibration, four available buffers (4.01, 7.01, 8.20, 10.01)
Temperature Compensation manual or automatic
mV Range -2000.0 to 2000.0 mV
mV Resolution 0.1 mV
mV Accuracy (@25ºC/77ºF) ±1 mV
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; 0.1 K
Temperature Accuracy (@25ºC/77ºF) ±0.4°C; ±0.8°F; ±0.4 K
Logging Data up to 400 ( 200 titrations, 200 pH/mV readings)
Electrode FC260B pH electrode with 1 m (3.3’) cable (included), HI5315 reference probe with 1 m (3.3’) cable (included)
Temperature Probe HI7662-M stainless steel temperature probe with 1 m (3.3’) cable (included)
Environment 0 to 50°C (32 to 122°F); RH max 95% non-condensing
Power Supply 12 VDC adapter (included)
Dimensions 235 x 200 x 150 mm (9.2 x 7.9 x 5.9”)
Weight 1.9 kg (67.0 oz.)
Ordering Information HI84529-01 is supplied with FC260B pH electrode, HI5315 reference electrode, HI7662-M temperature probe, HI84529-50 low range 20 titrant (120 mL), HI84529-52 low range 50 titrant (120 mL), HI84529-51 high range 20 titrant (120 mL), HI84529-55 calibration standard (230 mL), HI7072 fill solution (30 mL), HI700640 cleaning solution for milk deposits (2 x 20 mL), capillary dropper pipette, 100 mL beakers (2), dosing pump valve, 5 mL syringe, 1 mL plastic pipette, tube set (aspiration tube with titrant bottle cap and dispensing tube with tip), stir bar, 12VDC power adapter, instruction manual and quality certificate.

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