Quat Test Strips

Indigo® quaternary ammonium chloride test strips for optimal disinfection & sanitizing needs in restaurants, hospitals, organic farming & more.

All come with 100 test strips/vial and a guaranteed 3 year minimum shelf life. Full documentation: Certificates of Analysis, Stability & SDS Statements; Certificates of Conformance available on request. Optional next day delivery in any quantity of most items.

Buy Indigo® test strips, the brand you can trust for accuracy & technical support. Call us on our toll free line for immediate assistance or e-mail us with your questions. 1 hour response is typical during business hours, M-F, slightly longer on weekends.

Quaternary Ammonium (QAC) Disinfectants

Quaternary ammonium compounds are cationic surfactants (positively charged surface-active agents) that are more chemically complex than other disinfectants. Their name derives from the central nitrogen that is bound to four (quaternary) organic groups. They interfere with the metabolism of Gram-negative & Gram-positive vegetative bacteria and lipophilic viruses.

Quats are especially effective on hard, non-porous surfaces. They are used in a broad range of places from hospitals, long-term care facilities, households, essential workplaces such as grocery stores and food processing plants to high traffic outdoor common areas and public transit systems.

Quaternary ammonium compounds are also useful as wetting & emulsifying agents in acidic or neutral pH solutions, fabric softeners & as microbicides and fungicides.

Quaternary ammonium compound chemical structure

Quaternary ammonium compound disinfectant structure model from Indigo® Instruments.

Whatever formulation of quaternary ammonium you use, Indigo® quat test strips can confirm your disinfectant solutions are correctly diluted for optimum effectiveness.

Indigo® Quat/QAC Test Strip Ranges

  • 10-100ppm: ≤10-20-30-50-100ppm; read results in 10 seconds
  • 0-400ppm: 0-100-200-300-400ppm; read results in 10 seconds
  • 0-1500ppm: 0-200-400-750-1000ppm; read results in 5 seconds
  • 0-10000ppm: : 0-1000-2500-5000-10000ppm; read results in 5 second

Common Features of Indigo® QAC Test Strips

  • clear instructions with the labeled color chart
  • indicators on high contrast plastic for accurate readings
  • stiff plastic strips can be dipped into tubes
  • accurate from 5-45oC (50-110oF)
  • 3 year guaranteed shelf life
  • Certificate of Analysis & Stability Statement online; SDS & Certificate of Conformance on request.

Note: All test strips Made in the USA & are Q/A'd against NIST standards.

Displaying 1 to 4 (of 4 products)
QAC QR Test Strips 0-400 ppm

QAC QR Test Strips 0-400 ppm

SKU: 33819-400
$8.95USD or lower Each
Multi Quat Sanitizer Test Strips Dairy

Multi Quat Sanitizer Test Strips Dairy

SKU: 33819-1500
$13.95USD or lower Each
Quat Test Strips Very High Level 10000ppm

Quat Test Strips Very High Level 10000ppm

SKU: 33819-10K
$16.95USD or lower Each
Residual Quat 10-100 ppm

Residual Quat 10-100 ppm

SKU: 33819-100
$12.95USD or lower Each
More Information

Common Quaternary Ammonium Chlorides

Quaternary ammonium chloride solutions come in many varieties. Ours are calibrated for Oasis 146 but can accurately test any simple or multiquat formulation using compounds such as these: benzalkonium chloride, benzethonium chloride, methylbenzethonium chloride, cetalkonium chloride, cetylpyridinium chloride, cetrimonium, cetrimide, diisobutylphenoxyethoxyethyl dimethyl benzyl ammonium chloride,dofanium chloride, tetraethylammonium bromide, didecyldimethylammonium chloride, etc. You can view & compare their different chemical structures using our 3D Molecular Model Builder.

Advantages & Disadvantages


  • Nontoxic, odorless, colorless, noncorrosive, nonirritating
  • Relatively stable in the presence of organic matter
  • Active over a wide pH range but best in the range of pH 8-11


  • Slower at killing some microorganisms
  • Not compatible with some detergents
  • Not compatible with hard water
  • Color charts start to deviate at 45oC (110oF) & above

Additional material that may interest you:

  1. Quaternary Ammonium Compounds-Organic Disinfectants. What are quats, how do they work & how to dilute?
  2. Test Strip Expiration Dates; Good Today, Dead Tomorrow? Don't toss good test strips away. Good today doesn't mean bad tomorrow.
  3. Diluting Chlorine, Peroxide, Quats is Easy. Understanding metric makes it very easy to dilute disinfectant to any ppm from bottles to bucketfuls.
  4. Can 10ppm of Sulfite & Quat Really Mean Zero? Test strips are an inexpensive qualitative way to measure residual chemicals but they have their limits. They simply cannot measure below 10ppm which should be enough to assure you of safe levels.

How Quat Test Strips Work

Quat test strips do not measure the concentration of dissolved quaternary ammonium compounds (QACs) directly. They actually use acidobasic indicators (normally used for pH determination), buffers, surfactants, and other ingredients to create a micro-environment on the test pad where the indicator dyes react to the presence of the quat and not to the pH of the test solution. It is as a consequence of the interaction between the molecules of the indicator dyes and quat that results in a different color of the test pad that we observe.

This is based on what is known as the "pH indicator error" (when the indicators change color without a change in solution pH) which relies on a carefully calculated amount of buffer on the test strip that excludes any contribution to pH other than the quat itself. It is this "error" that is utilized for the detection of compounds of interest (The QACs in this case). In other words, the assumption is the quat has been dissolved in tap water that might be slightly acidic, neutral or slightly alkaline. "Alkaline water" for example would have absolutely no effect. However, some quat formulations have additives such as tetrasodium EDTA which strongly shifts pH towards an alkaline level of 11-12 that completely throws off the test strip reading.

Overall, this is a reliable semi quantitative test method that is accurate typically to +/- 10% & suitable for confirming the correct dilution of quat concentrates in the "field". For more precise lab work, instruments such as GC/MS can deliver quantitative results on the order of several magnitudes greater & over a wider dynamic range.

Temperature and QAC Strips PPM Reading Relationship

(Results for Hyamine 1622 (Fluka) warmed up from 35oC to 60oC (95-140oF))

T (oC)  vs QAC strips readings at: 0; 50; 100; 200; 400 ppm

35oC: Readings ok for 0-400ppm
40oC: Readings ok for 0-400ppm
45oC: 0, 50, 100 ppm readings ok; 200 & 400 ppm read~ 1/2 color square higher
50oC: 50, 100 ppm read~ 1/2 color square higher; 200, 400 ppm read 1 color square higher
55oC: Readings 1 color square higher across whole range
60oC: Readings 1 color square higher across whole range



Follow the directions on the label. All our quat strips are "quick response". Dip the strip & compare to the color chart within 5-10 seconds. If you wait a minute as with other strips, the color will develop further & give a false high reading.

Some sources have raised concerns about the safety of quaternary ammonium compounds. Handling concentrated QACs may merit wearing PPC such as gloves, eye protection and even a respirator.

Frequently Asked Questions

FAQ for Quat Test Strips

Yes. These didecyl dimethyl ammonium chloride, alkyl(C12-C16) dimethyl benzyl ammonium chloride, octyl decyl dimethyl ammonium chloride, dioctyl dimethyl ammonium chloride and others have been shown to kill molds. Read more in our blog: Quaternary Ammonium Compounds-Organic Disinfectants. If you are interested in the chemical structures of these compounds, you can view them in our 3D Molecular Model Builder

Absolutely not! Mixing concentrated chlorine bleach & quaternary ammonia compounds can produce toxic vapors.

Chlorine bleach contains sodium hypochlorite, a powerful oxidizing agent that can corrode most metals & react to produce toxic chlorine gas. Its principle advantage is that it is cheap & readily available. Quats are cationic detergents that are relatively low in toxicity by comparison but its surfactant nature produces a residual film with broad spectrum germicidal characteristics.

According to the Household & Commercial Products Association (HCPA): "Quats are a well-understood and effective class of chemicals, usually classified under the chemical names ADBAC and DDAC. Numerous reputable studies show no sign of systemic toxicity in humans". 

On the other hand, some articles do question the safety of quats. Considering the importance of surfactants in lung alveoli, it may be prudent to handle concentrated quats only in well ventilated areas or wear a respirator and goggles during the dilution process.

Lysol disinfecting wipes are infused with 0.26% benzalkonium chloride [aka Alkyl (C14, C12, C16) Dimethyl Benzyl Ammonium Chloride]. This is very close to 2500ppm so the best quat strip to confirm they are fresh is our 0-10000ppm quaternary ammonium test strips.