How to Use a Traditional Analog Handheld Refractometer


Different models of traditional analog refractometers have different internal scales on which to read fluid concentrations. Some instruments have specialized scales that indicate the exact mixture of the sample being tested, while others have an arbitrary unit of measure that works like a shorthand for refractive index measurements.

The instruction manual that comes with each refractometer carefully explains the procedure for comparing refractometer readings to the actual known concentrations or properties of your specific fluid. Trained MISCO technical support engineers are always available to assist you at any time.

How to Take a Reading With a Traditional Analog Refractometer

MISCO refractometers are easy-to-use and require little or no training. They can be mastered by ANYONE in just minutes.

  1. Place a drop of sample on the measuring surface beneath the ViewPoint Illuminator.
  2. Look through eyepiece and press the ViewPoint Illuminator.
  3. Take your reading at the point where the contrast line (difference between light and dark areas) crosses the scale.


How a Traditional Analog Refractometer Works

Light passing through a liquid is slowed compared to the speed it travels in air. So once a fluid sample is placed on the measuring surface of a refractometer, the light passing through it slows and is bent.

The refractometer focuses this bent light on a tiny internal scale. The scale is magnified by the eyepiece lenses so it is easily visible.

The optics are supported by a bi-metal strip that moves lenses in response to temperature changes, ensuring that readings are accurate regardless of temperature.



Chemicals (14)

Hello, I am looking for a handheld portable device to measure the % mass ethylene glycol in a glycol / water solution. Thanks.

The MISCO Palm Abbe digital refractometer can be programmed with scales for measuring the percent by weight or percent by volume of ethylene glycol (EG) in an ethylene glycol (EG) / water solution. Just use the filters in the digital handheld refractometer section of the MISCO website to find the refractometer that is right for you. If you don’t see what you need, please contact MISCO customer service and we will create a custom refractometer to your specifications.


Can the Palm refractometer be used to check Trieythelene Glycol?

Thanks for your question. The Palm Abbe digital refractometer can measure several triethylene glycol (TEG) physical properties including, percent by weight, percent by volume, freeze point, specific gravity, density, and boiling point.

Hi, I’m interested in purchasing a refractometer, but I am not sure which type is suited to my needs. I plan to use it in order to verify concentrations of Urea concentration. The temperature of the solution will be 35 degrees Celsius, and I want to use high concentrations, 6M-8M Urea. Can you please advise as to which device is best suited to my needs?

The Palm Abbe digital refractometer is ideal for measuring urea concentration. There are scales to read Molarity 0.0 to 8.6, as well as scales for percent by weight, specific gravity, density, freeze point (Celsius and Fahrenheit), and parts per thousand. The refractometer is automatically temperature corrected for temperatures between 10 to 45 °C (50 to 113 °F). If you can’t decide which urea scale that you need, that’s ok; you can select any five scales to be programmed into a Palm Abbe PA203x. Please give us a call, customer service will be happy to help you select the scales that you need.

Category: Chemicals

What is the difference between the traditional analog Brix refractometer and the electronic digital handheld for Glycol testing? What are the benefits to having one over the other?

This is a good question. Brix is a measure of sucrose content in a sucrose water solution. There is not a direct linear relationship between Brix and glycol concentration. However, there may be a conversion chart available from your glycol supplier or you can make your own (we do not have conversion charts). Our analog Brix refractometer has a precision of +/- 0.2% Brix. The analog refractometer scale is subjective, meaning that two or more people looking at the scale are likely to report different readings depending how they view the scale. You also need to bring the glycol near your face to take a reading. Brix refractometers are temperature compensated for sucrose not glycol. Lastly, since you need to use a conversion table to manually calculate glycol freeze point, you introduce the possibility of making an error. A Palm Abbe digital refractometer with a scale for glycol would be a much better choice. First, the reading is digital which removes subjectivity from the measurement. Second, you can read directly in the unit of measure you desire, concentration or freeze point. This eliminates conversion errors. Since you place your sample in a well, you do not need to bring the refractometer near your face to read it. Also, a digital refractometer with a glycol scale will have temperature compensation specific to glycol. Lastly, the Palm Abbe digital refractometer has at least twice the accuracy of an analog Brix refractometer.

What are all the different salt scales used for? I need to measure salinity content but don’t know what scale I need.

Chemically, salts are ionic compounds that result from the neutralization reaction of an acid and a base. There are several varieties of salts containing chlorides, acetates, fluorides, and sulfates. The most common salt is sodium chloride (NaCl) or regular table salt. Although we have a refractometer scale that will measure most common salts, we also have an extensive list of scales for sodium chloride. You may select from scales for measuring sodium chloride concentration in percent by weight, specific gravity, freeze point, parts per thousand (ppt), g/100g, density, percent saturation, and even Baume. The most common units of measure are percent by weight, percent saturation, and freeze point. The scale that is correct for you depend on what unit of measure you are most interested in. Multiple salt scales can be programed into the MISCO Palm Abbe digital refractometer so you can just change between different units of measure as your needs change. MISCO also has scales available for the salinity of seawater.

Very interested, yet ignorant about this technology. I need reliability in testing % NaCl in water softening applications as well as concentrations of sodium hydroxide, hydrochloric acid, and sodium sulfite. Do I need multiple instruments? Can I get the meter to read in ppm of sodium sulfite? Can the meter(s) read in % saturation of NaCl? I am used to reading hydrometers for all but sodium sulfite, can the instruments give the same read out in % acid or caustic? I really do not understand the BRIX scale and how that will look when all I want is the strength of acid or % saturation of NaCl. Thanks,

There are many scales available for the Palm Abbe digital refractometer. In general, refractometers are very good at measuring binary (two-part) fluids, such as sodium chloride (NaCl) and water. Where the sodium chloride is the variable and water is the constant. For these types of binary fluids, the resolution (detection threshold) is typically in parts per thousand (ppt). Measurements of concentrations in the parts per million rage is not possible with a handheld refractometer.

As long as you can accept measurements in the parts per thousand, percent saturation, or concentration, then a refractometer would be useful for you. We have scales available for directly measuring sodium chloride (NaCl), sodium hydroxide (NaOH), hydrochloric acid (HCL), and sodium sulfate (Na2SO4), provided that your fluid is just one of those chemicals and water. If there are more than two parts to the solution, a refractometer could not discriminate which part was causing a change in the overall refractive index.

The Brix scale is a measure of the percent of sucrose in a sucrose/water solution. This scale would not be of any use to you unless you have a conversion table.

Check out our Build Your Own Page and put together scales that make sense for your full application.

Category: Chemicals

I am wanting to find out if you have a handheld meter that can measure: TEG EG DEG PG MEA DEA DGA Any assistance that you can provide would be greatly appreciated.

Scales are currently available for the Palm Abbe digital refractometer that can measure EG (ethylene glycol), PG (propylene glycol), TEG (triethylene glycol), DEG (diethylene glycol), MEA (Monoethanolomine), DEA (Diethanolomine), and DGA (Diglycolamine). Please contact MISCO customer service for details on ordering, or see the Build-Your-Own section of our website.

I would like to obtain some additional information regarding your PALM ABBE PA202X-011-014 ethylene glycol refractometer. Our enquiry is related to the use of the refractometer for measuring runoff and surface waters for ethylene glycol. Specific questions are:

1. Units of measure. Does the instrument have the capability of reporting measurements in mg/L?

mg/L is a tough number to display on the refractometer. Refractometers typically measure in the parts per thousand range. Mg/L is parts per million. This is well beyond the detection threshold of most handheld refractometers.

2. What is the range (lower detection limit and upper limit) of detection of the instrument in mg/L?

0 to 1,000,000 mg/L Theoretical.

3. If there is an upper range, is there a procedure specified for sample dilution?

Upper range would be 100% EG. No dilution would be necessary.

4. Are there any properties of the matrix (water) that may interfere with the analyses (e.g., suspended solids, dissolved solids, pH)?

Dissolved solids are additive to refractive index. Any dissolved solids besides EG would cause an error in the reading. Most suspended solids should have no effect on the readings.

5. What is the precision and accuracy of the measurements (+/- in terms of mg/L)? Does the accuracy/precision vary according to sample concentration?

The average full scale precision would be approximately +/- 1.500 mg/L.  and Yes. It is approximately +/- 1.395 at the bottom of the scale and +/- 3.966 at 100% EG.

A vendor gave me your website to try and locate a meter that could tell me the percentage of Diethanolamine contained in a deionized water solution. We typically run approximately 25-30% DEA solution, and add deionized water or diethanolamine (DEA) to maintain this concentration. Do you provide a hand-held instrument that could analyze this for us?

Thanks for your question. The Palm Abbe digital refractometer can be programmed with scales to read Diethanolamine (DEA) from 0 to 100 percent by weight. Just place a few drops of Diethanolamine (DEA) on the measuring surface, close the evaporation cover, and press the button to get an instant reading of concentration.

When using this to test % PG in water, is it possible to get a false positive at low levels (e.g., 0.1, 0.2)? Does the turbidity of the sample have any effect?

The uncertainty of the Palm Abbe digital refractometer PA203X with a propylene glycol (PG) scale is +/-0.1%. So, if you are testing pure water there is always the possibility of receiving a reading of either -0.1% or +0.1% concentration. To minimize the possibility of an erroneous reading, you can take multiple readings and average them together. Generally, turbidity caused by suspended solids will have little effect on refractive index measurement.

Full question

We just purchased a MISCO digital salometer for measuring sodium chloride concentration. We have a process that needs to mix DI water with Sodium Chloride (NaCl) to 100% saturation. I am hoping that the meter I have bought is the correct version for this job?

The MISCO Digital Salometer is a refractometer that measures the percent saturation of sodium chloride (NaCl) salt in water. The refractometer will display the percent saturation of sodium chloride from 0 to 100% as well as display the freeze point of the solution in either Fahrenheit or Celsius (model dependent). A digital Salometer overcomes many of the problems associated with traditional analog Salometers. Traditional Salometers are cumbersome to use and time consuming. They are simply a glass or plastic hydrometer with a special scale that displays degrees SAL instead of specific gravity. In use, the traditional Salometer is floated in a graduated cylinder containing salt brine. The reading is taken at the point at which the surface of the fluid crosses the analog scale divisions; the temperature must then be read with a thermometer, followed by a manual temperature correction of the reading.

There is no method for field calibrating the apparatus; it is difficult to resolve the tiny scale divisions; it must be thoroughly cleaned and dried to prevent salt residue from influencing subsequent readings; and it is easily broken. The MISCO Digital Salometer is much easier to use and much more accurate. Simply place a couple of drops of sodium chloride solution on the measuring surface, close the evaporation cover, and press the button to initiate the readings. The percent saturation is displayed nearly instantly on the large LCD display.


Sodium Chloride Salt Brine Refractometer Salometer,  Sodium Chloride Salt Brine , Percent Saturation , Freeze Point in °C

Sodium Chloride Salt Brine Refractometer Salometer,; Sodium Chloride Salt Brine,; Percent Saturation Freeze Point in °F


We have a pool with 18% salt (a mixture of NaCl, CaCl2 and MgCl2). Is there a digital device [refractometer] that can measure the % of salt in the water?

I have some concerns about your ability to measure percent salt in a multi-component mixture with a refractometer. You see, refractometers are very good at measuring binary (two-part) mixtures such as sodium chloride and water, where the refractive index value of water is a constant (static or known) and sodium chloride is the variable. However, when there are many different components in a solution, such as sodium chloride (NaCl), calcium chloride (CaCl2), and magnesium chloride (MgCl2), it is difficult to tell what the contribution is that each component makes to the total refractive index.

So, if the refractive index changes, it is impossible to say, with any certainty, which of the component parts has changed. Since a refractometer only measures the total refractive index of a solution and cannot selectively read the refractive index of one particular component. All water soluble fluids look the same to the refractometer. Therefore it will be impossible to get a reading that is meaningful.

The Palm Abbe refractometer does have scales for binary solutions of sodium chloride (NaCl), calcium chloride (CaCl2), and magnesium chloride (MgCl2), but cannot measure a mixture of all three.

I’m interested in testing calcium chloride (CaCl2) at a 30% concentration. This would be to verify identity of totes. Is this possible with a refractometer?

The MISCO Palm Abbe digital refractometer can be programmed to measure calcium chloride. In fact there are several calcium chloride scales that can be programmed into the Palm Abbe refractometer to measure calcium chloride percent by weight, grams/ 100 grams, ppt, density, specific gravity, and freeze point in both Fahrenheit and Celsius. All of the Calcium Chloride scales can measure the equivalent of 0 to 40% w/w, with the exception of the freeze point scales which measure to the maximum freeze point.

Categories: Chemicals, Deicing

I have a gas dehydration system which used TEG. Typical concentrations of Tri-ethylene Glycol (TEG) vary from 88% to 98%. Do you have a device that could measure the concentration of TEG to within +/- 0.5%. The typically impurities are 1) water ( 2-12%) and 2) oil (300- 1000 ppm). Thanks in advance.

No problem. Our Palm Abbe digital refractometer can measure the percent concentration of triethylene glycol (TEG) in your dehydration system from 0 to 100 percent (+/- 0.1%). You can choose a scale for TEG percent by concentration or TEG percent water. The oil contaminate should not be a problem because the refractometer only measures in the parts per thousand (ppt) range, not in parts per million.