HI97769 Anionic Surfactants Portable Photometer: Range 0.00 to 3.50 mg/L - meter only

Present in waters and wastewaters, surfactants are discharged via aqueous waste from households, industrial laundering, and other cleansing operations. Generally present in detergents and other cleaning agents, a surfactant molecule consists of a strongly hydrophobic group and a strongly hydrophilic group, permitting solubility in both aqueous and non-aqueous media. When the hydrophilic group is negatively charged, it is deemed an anionic surfactant; when the hydrophilic group is positively charged, it is deemed a cationic surfactant.

The HI97769 uses an adaptation of the USEPA method 425.1 and the Anionic Surfactant as MBAS method per Standard Methods for the Examination of Water and Wastewater to measure anionic surfactant concentrations of less than 3.50 mg/L (ppm) (as sodium dodecylbenzenesulfonate [SDBS]). When the methylene blue reagent is added to samples containing anionic surfactants, the sample will turn a blue hue; the greater the concentration, the deeper the color. The associated color change is then colorimetrically analyzed according to the Beer-Lambert Law. This principle states that light is absorbed by a complementary color, and the emitted radiation is dependent upon concentration. For anionic surfactant determination, a narrow band interference filter at 610 nm allows only orange light to be detected by the silicon photodetector and omits all other visible light emitted from the LED. As the change in color of the reacted sample increases, absorbance of the specific wavelength of light also increases, while transmittance decreases. Using a pre-programmed curve a result is then displayed.

The HI9769 has an innovative optical system that offers superior performance in accuracy, repeatability, and the short amount of time it takes to perform a measurement. This compact, waterproof meter is extremely user friendly with a tutorial mode that walks the user graphically, step by step, in performing a measurement. The use of a backlit dot matrix LCD allows the use of virtual keys which makes the operation of the meter very intuitive including selecting different units of measure, reviewing GLP data, recalling the last 50 measurements, and customizing the meter to user preferences.

HI97769 is completely waterproof including the cuvette holder that is designed with ridges to protect the optical path from getting scratched by the cuvette and a gasketed battery compartment that holds three common AA batteries. The compact design fits comfortably in the hand for use in the field or on a table for benchtop use. The LCD is backlit for easy viewing under all conditions.

 

• LED that generates very little heat.

• 8 nm narrowband interference filter that is accurate to +/- 1 nm.

• Reference detector that modulates the voltage to LED for consistent light output. 

• A concave focusing lens that reduces errors from imperfections in the cuvette.

On-Screen Features

CAL Check
Advanced features including CAL-Check to verify performance and if necessary, recalibrate.

Setup Options
Setup options for meter personalization include date and time format, language, and enabling the tutorial mode.

Tutorial Mode
Tutorial mode for step-by-step instructions to guide a first-time user in how to perform a measurement correctly.

Reaction Timer
Built-in reaction timer that ensures consistency amongst multiple users.