Waterproof portable digital refractometer, sodium chloride in seawater HI96822 HANNA

Waterproof portable digital refractometer, sodium chloride in seawater HI96822 HANNA

Description

The HI96822 is a portable and robust digital refractometer designed to measure the salinity of natural or artificial seawater. The HI96822 reports results in three different units of measurement: Practical Salinity Units (PSU), salinity in parts per thousand (ppt), and Specific Gravity (SG (20/20)). The operation of the instrument is simplified with only two buttons: one for calibration with distilled or deionized water and the other for measurement. The instrument's high accuracy and simple operation allow for reliable and precise results. All measurements are automatically compensated for temperature changes and displayed within seconds. The glass prism and stainless steel measurement cell are easy to clean.

More information

The HI96822 digital refractometer eliminates the uncertainty associated with mechanical refractometers by measuring the refractive index to determine the salinity of natural and artificial seawater, including brackish water, seawater, or marine aquarium water. The instrument converts the refractive index of a sample into PSU, ppt, and density. These conversions are based on scientific publications that consider the physical properties of seawater (and not sodium chloride). The HI96822 is an easy-to-use instrument for measuring salinity in natural and artificial seawater, whether in the field, in the laboratory, or at home.

- Designed for the analysis of salinity in seawater (without NaCl)
- Automatic temperature compensation
- High precision measurements displayed in PSU, ppt, and density

Index of refraction

The HI96822 performs measurements based on the refractive index of a sample. The refractive index is the measurement of light passing through the sample. Depending on the composition of the sample, the light refracts and reflects differently. By measuring this activity with a linear image sensor, the refractive index can be used to determine the physical properties of the sample, such as concentration and density. In addition to the linear image sensor, the HI96822 uses an LED, a prism, and a lens to make the measurement possible.

Temperature changes will affect the accuracy of refractive index measurements, so it is recommended to use automatic temperature compensation. The HI96822 has an integrated temperature sensor and is programmed with temperature compensation algorithms that convert the refractive index into: PSU (Practical Salinity Units), ppt (parts per thousand), or SG (Specific Gravity) (20/20). The PSU is defined as the ratio of the conductivity of a seawater sample to that of a standard KCl solution. It is based on the work of UNESCO, ICES, SCOR, and IAPSO. This information is published in the "Joint Panel on Oceanographic Tables and Standards." ppt is an older scale (10^-3), where salinity is defined as: "The salt content is the weight of inorganic salts present in 1 kg of seawater if bromides and iodides are replaced by an equivalent amount of oxides" (Knudsen, 1901). The density (20/20) is based on the published relationship between the density at 20°C and the mass of dissolved salts in the seawater sample (CRC Handbook of Chemistry and Physics, 87th edition).

Characteristics

Single-point calibration:
- Calibrate with distilled or deionized water

Small samples:
- It is also possible to measure only 2 drops of sample (100 μl)

Automatic Temperature Compensation (ATC):
- The samples are automatically compensated for temperature variations.

Quick and accurate results:
- The results are displayed in approximately 1.5 seconds

Two-level display:
- The dual-level display shows the measurement and the temperature simultaneously

Stainless steel sample measurement cell:
- Easy to clean and resistant to corrosion

Battery indicators:
- Percentage of remaining battery charge when starting the instrument and low battery indicator

Automatic stop:
- To save battery, the player automatically turns off after three minutes of inactivity.

Waterproof, IP65 protection:
- Waterproof ABS plastic enclosure designed for field and laboratory measurements.

Use

Sodium chloride solutions can be used to verify the accuracy of the instrument. The table below indicates two sodium chloride solutions and the expected value of brackish water in ppt.

To prepare a standard NaCl solution (g / 100 g), follow the procedure:

- Place a container (such as a glass vial or a bottle with a cap) on an analytical balance.

- Tare the scale.

- Weigh X grams of pure sodium chloride (CAS #: 7647-14-5: MW 58.44) directly into the container.

- Add distilled or deionized water so that the total weight of the solution is 100 g.