C-07

Chemical metrology

Calibration for the instruments that measure chemistry itself — pH and conductivity — against certified reference materials.

What it is: pH meters, conductivity meters
Who it is for: Laboratories, water treatment and food production lines
Turnaround: 3–10 working days

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METHOD

Reference standards

pH meters
TEC-CAL-SCM-04
APHA, AWWA and WEF standard methods
Conductivity meters
TEC-CAL-SCM-02
APHA, AWWA and WEF standard methods
TDS meters
TEC-CAL-SCM-01
Laboratory procedure

Applies to	Procedure	Built on
pH meters	TEC-CAL-SCM-04	APHA, AWWA and WEF standard methods
Conductivity meters	TEC-CAL-SCM-02	APHA, AWWA and WEF standard methods
TDS meters	TEC-CAL-SCM-01	Laboratory procedure

Procedure references are the laboratory’s own controlled methods. Accredited scope is defined by the annex to certificate N-C-00592 and is stated separately — a published procedure is not a claim of accreditation.

WHAT THIS IS

What this is, and why it matters

Chemical metrology calibrates the instruments that turn a chemical property into a number. A pH meter is compared against certified buffer solutions at defined points — the accredited scope publishes 4, 7 and 10 pH — and a conductivity meter against a certified reference solution, with the deviation and its uncertainty recorded at each point. The reference materials themselves are certified and traceable, which is what separates a calibration from a routine buffer check on the bench.

These are instruments whose drift is invisible and whose readings carry decisions. A pH value can sit behind a release limit, an acidity specification or a cleaning-verification step; conductivity readings govern rinse water, reverse-osmosis performance and utility water. The daily on-bench buffer adjustment keeps an instrument usable — it does not make it traceable, and it produces no record an auditor can accept. Calibration does both.

What this lane covers

pH meters and conductivity meters, on the accredited scope
Wider analytical instruments confirmed at quotation

TRIGGERS

When you need it

A pH value sits behind a release decision

Where acidity is a specification limit or a process control point, the meter reading it must be traceably calibrated, and the daily buffer check does not discharge that requirement on its own.

Conductivity governs a water system

Rinse-water verification, reverse osmosis and utility water monitoring all run on conductivity. A drifting cell constant moves every one of those checks quietly.

An audit asks for the traceability behind the number

ISO/IEC 17025 laboratories and the food safety schemes expect chemical measurement instruments on a documented calibration interval, with certificates that name the reference materials used.

PROCESS

How it works

Identify the instrument and the range you use
Instrument type, make and model, and the points your process actually uses. pH meters are calibrated at the accredited buffer points; conductivity meters against certified reference solutions. Instruments beyond these two families are confirmed in writing before anything is booked.
Coverage confirmed against the accredited scope
The laboratory confirms whether your instrument and range sit inside the accredited scope before quoting. Where they do not, that is said plainly rather than quietly absorbed — the scope annex is published on this site precisely so the boundary is checkable.
Measured as found, before any adjustment
The as-found reading is recorded first, always. It is the only evidence of whether the measurements you have already taken and acted on were sound, and adjusting the instrument before measuring it destroys that evidence permanently.
Certificate issued against traceable references
The certificate states the measured deviation at each point, the uncertainty, and the certified reference materials used with their traceability.

What you get back

A calibration certificate identifying the instrument, each buffer or reference point with its deviation and uncertainty, and the certified reference materials behind it — one document, one traceability line.

Scope facts

Parameter	Value	Note
Accreditation basis	Accredited. Chemical measurements are on the annex to certificate N-C-00592: pH meters and conductivity meters, with the accredited range and CMC published per line.	Stated per discipline, from the scope annex.
Accredited ranges and CMC	Calibration: mass, mechanical, temperature and chemical measurements, published line by line with range and CMC. Testing: food and agricultural microbiology, covering aerobic plate count, Escherichia coli, coliforms and Enterobacteriaceae.	Publishes from the scope annex. No range is estimated.
Collection and on-site service	Non-portable instruments are calibrated at your premises. Portable items may be submitted to the laboratory, or collected by our personnel for an additional pickup fee. Standard turnaround is 3 to 10 working days from acceptance.	Confirmed service routes only.

Q+A

Common questions

Chemical

What does the certificate show?

The instrument identity, the measurement points, the measured values, the uncertainty at each point, and the reference standards used. One document, one traceability line.

Can this be bundled with certification work?

No. Calibration is a technical service and stays separate from any certification decision. The lab does not sell audit outcomes.

Which ranges are available?

Ranges and CMC values publish from the accredited scope annex only. Name the instrument and the range you use; the lab confirms coverage before quoting.

Send the sample question or the instrument list. It is read by a bench professional, not routed through a ticket queue. Call +966 59 637 8052 or write to lab-mgr@qsinexus.com.

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