pH measurement of paper, leather, and other surfaces are important during manufacturing and final product stages. In the paper industry, a pH measurement indicates the chemical stability and permanence of a paper. It is desirable to manufacture paper that has a neutral or slightly basic pH to aid in the preservation of important documents, publications, and artworks. An acid-free or alkaline paper is able to absorb damaging acid compounds that are naturally formed through aging.

pH of paper and cartons is also important in the food industry. Food packaging often incorporates antimicrobial agents to inhibit microbial activity during distribution and storage conditions. The activity of antimicrobial agents can quickly change with a variation in pH. pH compatibility tests consider food composition, chemistry of the antimicrobial agents used, and packaging material.

In leather making, tanning is one of the most chemically complex steps. Generally, tanning creates a leather product that is more breathable, flexible, and suitable for use in handbags, luggage, garments, and a variety of commercial items. Tanning is performed by a vegetable method or chrome method; chrome-tanned leather requires the addition of chromium salts and a basic component to raise the pH. The pH of the liquors used in the leather making process and the pH of the final leather product directly affect characteristics such as firmness, heat resistance, and durability.

The HI99171 uses the HI14143 amplified pH electrode with glass body. This specialized electrode offers numerous features that improve surface pH testing. An integrated temperature sensor allows for temperature compensated pH measurements without the need for a separate temperature probe. The probe’s flat sensing tip provides optimal surface contact with samples.

An integral part of any pH electrode is the reference junction. The reference junction is a part of the electrode that allows for the flow of ions located in the reference cell into the sample being tested. It is vital that this flow occurs in order to complete an electrical circuit, which ultimately determines the pH value. Poor contact between the junction and sample will prevent completion of the circuit, resulting in readings that are erratic or constantly drifting.

The flat tip of the HI14143 provides optimal surface contact between the sample and the junction. The HI14143 features an open junction design which utilizes a viscolene reference electrolyte that comes into direct contact with the sample, providing accurate, stable readings.

Features at-a-glance

Waterproof - The HI99171 is a waterproof meter rated IP67 for immersion in up to one meter of water for 30 minutes.

Automatic Calibration - One or two-point calibration is automatic to two selectable buffer sets.

Automatic Temperature Compensation – An integrated temperature sensor allows for automatic temperature compensation of pH measurements.

Sensor Check - Using the pH‐mV range the user can check the sensor status by reading the mV reading in fresh buffers. At room temperature (25 oC/77oF) the reading should be +/- 30 mV in pH 7.01 and greater than 150 mV difference between pH 7.01 and 4.01.

Multi-Level LCD Display - The split-level LCD displays both pH and temperature readings, along with indicators for reading stability, battery percentage, and probe condition.

Probe Condition Indicator - The probe condition indicator is based on the offset and slope characteristic of the electrode. There are 5 bars ranging from all 5 indicating the probe is in excellent condition and 1 bar indicating the probe should be cleaned or replaced.

Battery Error Prevention System - The meter will automatically shut off if there isn’t enough power to obtain an accurate measurement.

Battery Life Indicator - The battery percent level is displayed at start up alerting the user to the remaining battery power that is available.