Published on 05/12/2020 | by Waterline Admin

As featured in waterline Spring 2020


Nick Barsby, ADEY

What’s a matrix type?
A matrix is the specific type of a sample; for instance a type of sample is a water, but this can cover a wide range of matrix types, from Drinking Water through to Untreated Sewage.

What do UKAS say?
Accredited organisations (laboratories) will be expected to have sufficient validation data to demonstrate the capability of the method for the matrices detailed on their schedule of accreditation. Prior to the testing or sampling, and during contract review, the accredited organisation (laboratory) should establish that their methods/validation data match those for the specified matrix to be tested and are suitable for their customers’ specific requirements.

What are the UKAS Sample Matrix Types?
In May 2019 UKAS produced an updated list of sample matrix types that laboratories can claim accreditation against, these are:

Do I need to tell the laboratory my sample matrix?
Yes! The matrix is a critical part of the sample submission and testing process. This should be clarified at the quotation stage to ensure that the laboratory can process the samples, or find an appropriate subcontractor (if applicable).

Why is it important?
Matrix type is important for numerous reasons.

When a laboratory performs a validation study for their UKAS accreditation they do this against specific matrix types and as part of this UKAS submission the laboratory provide precision, bias and uncertainty of measurement data. This forms part of the accreditation process.

If a laboratory were to process a Treated Sewage sample on a Drinking Water method it would have significant implications on the original sample and could lead to damage to the analytical instrument, carryover contamination or breaches of Quality Control data.

What happens if I submit a sample matrix that’s not accredited?
If you submit a sample to a laboratory with a matrix that they are not accredited for then your test result will not hold UKAS accreditation. The laboratory could still provide a result for this matrix type, but the accuracy of this result could be affected.

Why are UKAS introducing Sample Matrix Types?
Laboratories have always had specific methods for specific tests and types of samples. The labs have also held accreditation against certain matrices. The change to customer requirements on matrix type has been driven to improve the end user’s data set.

In the past a laboratory could have attained UKAS accreditation for Legionella on a Drinking Water and claimed UKAS accreditation for a wide range of Water types; even if the method was not fit for purpose. Now, with Sample Matrix level accreditation and reporting, labs can only claim accreditation against sample matrix types they have been validated against.

The change means that end users can have greater confidence in the data that the analytical laboratory provides, even if it does place an additional burden on the Water Treatment company.

When did sample matrix types become important to UKAS?
Every year UKAS audit the laboratory and review how they are performing against the ISO 17025 standard. As part of the 2017 update to the ISO it’s now even more critical to make sure that clients of laboratories understand the implications of applying the right test to the right type of matrix.

UKAS issued a proposed set of sample matrix types in June 2014 through a Technical Guidance Bulletin; from this point all laboratories had a reference point to “standard” water matrix types. This Guidance has been revised in May 2019 with the addition of a Healthcare matrix for hospital specific tests, such as Dialysate Waters, Endoscope waters and the like.

How do I know what Matrix type my sample is?
UKAS have provided a useful reference guide to sample matrix types that can be found below; if you are unsure about the classification of your matrix type then speak to your laboratory before submitting samples.

Product Spotlight

Single Syringe Test Kit

The world’s fastest Legionella test! Get results on site for the strain of legionella that causes practically all legionnaires’ disease cases and outbreaks in only 25 minutes. On site results removes the risks associated with transportation of samples. Simple to use, no specialist training required. Why would you wait days for test results? Contact us at Wycombe Water a Hydrosense distributor.

Neptune Water Safety

Neptune is an enterprise-grade, web-based water safety monitoring system which uses discrete, wireless multi-probe thermocouple devices that are easily attached to water assets in order to help maintain the safety of an organisation’s water system. By continually monitoring and analysing temperatures and flow events over time, Neptune helps identify conditions likely to create harmful bacteria such as Legionella or cause freeze or scald risk, improving safety for building users.

PrimeLab Photometer

The PrimeLab photometer hand-held Bluetooth® device is expandable and portable, developed for ultimate flexibility for use in a range of water systems. With only one light source and the JENCOLOR multi-spectral sensor used exclusively in the PrimeLab, it is possible to measure all water parameters where the water sample is visibly discoloured after addition of a reagent. Key Features of PrimeLab Photometer: The first and only PrimeLab photometer with just 1 LED / 1 JENCOLOR sensor, covering the 400 wavelength (380nm-780nm). More than a 100 different parameters available. Activation of add-on parameters is possible even after purchase. Powerful PC-software and app with free cloud service. Creating reports and dosage recommendations by just a click, using your individual water treatment chemicals.

Huwa-San TR-50 Silver Stabilised Hydrogen Peroxide

Huwa-San TR-50 is a commercial water disinfectant and biocide designed for shock disinfection or constant dosing. Huwa-San TR-50 kills legionella bacteria and in addition removes biofilm. It is safer to use than chlorine as the disinfection breakdown products are oxygen and water. Independent testing shows that Huwa-San TR-50 provides a very wide spectrum of biocidal activity against bacteria, viruses, spores, fungi, amoebae (such as amoeba acanthus which can act as a host to legionella bacteria) and algae. Use disinfectants safely. Always read the label and product information before use.

MC1+ Protector

Formulated to prevent wear and tear and the resulting debris, MC1+ stops magnetite and other deposits forming. As it does this, it protects the central heating, keeping the boiler working efficiently and helping to ensure the system lasts for longer.

MM2050 - PT100 Thermometer

Four/three/two wire measurement, Max/min functions, Hold function, Dual display, °C/°F/°A selectable, Simultaneous display of real time and max/min/hold measurement, Self calibrating.

MD610 Photometer

The MD610 gives you a mobile device in a modern design with the analytical features of a laboratory photometer. All important water analysis parameters from A(luminium) to Z(inc) are covered. Combined with the high precision of Lovibond® reagents, a reliable and quick analysis of water samples is guaranteed. Reagent tablets, powder reagents, liquid reagents, or cuvette tests are used depending on the method.

Armitage Shanks Markwik 21


(TB H2a) an integral thermostatic bib mixer tap, single long lever mixer. Single flow fixed horizontal nozzle, sequential operation. Sequential operation ensures both hot and cold supply are purged on each use, long lever gives precise control. Insulated technology keeps the ‘hot’ side of the mixer at a safe surface temperature.

AS Shower chrome

AS Shower chrome

Legionnaires‘ disease is usually spread by the breathing in of water vapour containing Legionella bacteria which is then deposited on the lungs. The bacteria thrives in water temperatures between 25 and 45°C and so showers by their very nature create an ideal environment for the bacteria to spread. The AS SHOWER chrome filter provides reliable and immediate protection against Legionella, removing bacteria at the point of use, allowing users to shower safely.