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The CHEMets® Test Method

Visual Colourimetric Analysis

Snap Tip • Mix • Compare

Immerse the narrow end of the CHEMet ampoule into the sample and snap off the tip (Step 1). The correct volume of sample is automatically drawn in, filling the ampoule. A small, inert gas bubble remains in the ampoule.

To facilitate mixing, tilt the ampoule back and forth so the bubble travels from end to end (Step 2). In two minutes or less, quantify the result by comparing the developed colour in the filled ampoule with the colour standards in the comparator (Step 3).

For higher concentrations, the flat comparator is used (shorter path length). For lower concentrations, the round comparator is used (longer path length). The ampoule is compared with the standards until a colour match is found.

Why CHEMets?

CHEMets Test Kits have a number of advantages over traditional visual (non-instrumental) water testing kits.

Like-for-Like Comparison

Traditional water test kits often use a printed colour chart which may not exactly correspond to the colour developed in the test tube. Test strips in particular may only correspond to the colour chart in certain parts of the test range.

CHEMetrics ampoule-based comparators allow for a like-for-like comparison between the test amouple and the colour standard, enabling more consistent and accurate test results to be obtained than traditional methods. Click left to view a video or read this article for more detailed use of a colour comparator.


CHEMetrics patented, self-filling ampoules simplify and speed up water testing procedures. They eliminate the potential inaccuracies associated with manual sample and reagent volume measurement in the field. There is no measuring or mixing of reagents required. The chemical reaction is contained within the ampoule so it is safer. more

Selected CHEMets round comparators can be used with the CHEMetrics Comparator Light Source (CLS), an independent light source for use in low-light locations.


CHEMets ampoules are designed for maximum simplicity and accuracy. Each glass ampoule is 7 mm in diameter, 100 mm in length, with a tapered, pre-scored tip; colour forming reagents are vacuum-sealed inside.

Kits include: 30 ampoules, comparator(s), accessory solution(s) (when necessary), a sample cup, and instructions. Safety Data Sheets (SDSs) are available here. Refill packs of 30 ampoules and accessory solutions are available separately. Most comparators have a 2-year shelf-life.

Analyte Range

Please see the Visual Products page for a complete list of available CHEMets and ULR (Ultra Low Range) CHEMets test kits.