Primary configuration
P9 Series pH/Conductivity/DO Meters
pH, conductivity and dissolved oxygen in one benchtop meter — the three parameters every water sample needs.
Not a replacement for ion chromatography on trace anions.
Water
Water & Environment
Instrument selection for drinking water, surface water, groundwater and treated wastewater — from field parameters to trace metals.
In short
A water laboratory almost always needs four groups of instruments: electrochemical meters for pH, conductivity and dissolved oxygen; a spectrophotometer with a digestion block for COD and nutrients; an ion chromatograph or a titrator for ionic composition; and an atomic absorption spectrometer for trace metals. Most laboratories start with the first two groups and add separation and elemental analysis when the reporting list requires individual ions or µg/L metals.
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- routine measurements
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- instruments in the recommended set
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- application notes
What the laboratory measures.
The routine tasks behind a typical quality programme, the parameters involved and the instrument group that covers them.
| Measurement task | Parameters / range | Typical method | Instrument group |
|---|---|---|---|
| pH, conductivity, dissolved oxygen | pH 0–14 · 0–200 mS/cm · 0–20 mg/L | Direct immersion, electrochemical | pH / conductivity / DO meters |
| Turbidity | 0–1000 NTU | Nephelometry | Turbidity meter |
| Colour and single-wavelength absorbance | 0–2 Abs | Colorimetry at a fixed wavelength | Colorimeter |
| COD | 5–1500 mg/L after dilution | Digestion followed by a colorimetric finish | Digestion block + colorimeter |
| Ammonia, total phosphorus, total nitrogen | 0.01–10 mg/L | Digestion and colorimetric determination | Digestion block + spectrophotometer |
| Major anions: chloride, nitrate, sulphate, fluoride | 0.01–100 mg/L | Ion chromatography with suppressed conductivity | Ion chromatograph |
| Trace metals: lead, cadmium, copper, chromium, nickel | µg/L range | Flame or graphite furnace AAS | Atomic absorption spectrometer |
| Alkalinity and hardness | 10–500 mg/L as CaCO₃ | Titration to an electrochemical endpoint | Potentiometric titrator |
| Reference standard weighing | 0.1 mg | Gravimetric preparation | Analytical balance |
Workflow
From sample to reported result.
Most results are decided before the instrument is switched on. These are the steps where laboratories usually lose accuracy.
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Define the reporting list
The parameter list decides the technique. Choosing the instrument first usually ends in a second purchase.
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Sample and preserve
Filtration, acidification and holding time decide whether the result is valid before any instrument is involved.
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Digest or prepare
Recovery for metals and nutrients depends on the digestion step far more than on the detector.
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Measure inside a bracketed calibration
The calibration range must contain the sample. A diluted sample read outside the curve is an estimate, not a result.
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Review with QC samples
Duplicates, blanks and control charts show drift before the regulator does.
Recommended instruments.
Start from a complete configuration rather than a single instrument: the supporting units decide whether the workflow runs without interruption.
Primary configuration
COD Analyzer B-COD
A dedicated COD workflow: digestion tubes, heating block and colorimetric reading specified as one set.
Samples above the linear range still need dilution and re-reading.
Primary configuration
BT-2000H Turbidity Meter
Nephelometric turbidity for drinking water and effluent reporting, with cells and calibration handled in the instrument.
The portable PT-2000H is the field equivalent; this unit stays in the laboratory.
Supporting
IC hope 1800 Ion Chromatograph
Anion profiles from µg/L to mg/L with suppressed conductivity, for laboratories reporting several anions from one injection.
Needs eluent preparation, a water system and column care routines.
Supporting
AA 7800 Atomic Absorption Spectrometer
Flame atomic absorption for the common metals at mg/L to sub-mg/L levels.
Below flame detection limits the graphite furnace version is required.
Supporting
YKJ-24S Digestion Instrument
Batch digestion for COD, total phosphorus and total nitrogen, sized for a routine sample load.
It changes throughput, not sensitivity — the reading instrument still decides the result.
Entry / alternative
Colorimeter BC-2000H
Fixed-wavelength colorimetry for standard parameters without paying for a scanning instrument.
No wavelength scanning, so method development still needs a spectrophotometer.
Entry / alternative
MIS1000 Mobile Multi-Parameter Analyzer
Field rounds, emergency sampling and sites without a laboratory bench.
Benchtop accuracy depends on benchtop calibration; treat field values as screening.
Application notes.
Method detail, common errors and configuration choices, written for this workflow.
Application note
Choosing instruments for drinking-water testing
Which instrument groups a drinking-water laboratory actually needs, in what order to buy them, and where the routine…
Application note
Drinking Water Screening: Plan Parameters Before Instruments
Which parameters a drinking-water laboratory must map before comparing instruments, and why the reporting range decides the bench…
Application note
Environmental Water: Managing Matrix Effects in Routine Analysis
How surface water, groundwater and wastewater change preparation, calibration and quality control — and where matrix effects are…
Most water laboratories buy in the wrong order. The first purchase is usually the instrument that appears most often in the procedure, not the one that decides whether the report can be issued at all. A short sequencing exercise avoids that.
Start with the parameters measured every day and needing no sample preparation: pH, conductivity, dissolved oxygen and turbidity. They cost little per result, they fail loudly when an electrode is dirty, and they set the routine the laboratory lives by. Add digestion and colorimetry next, because COD and the nutrient parameters share the same bench, the same glassware and the same batch rhythm. Separation and elemental analysis come last, when the reporting list genuinely needs individual anions or trace metals.
Two practical points decide more outcomes than the specification sheet. The first is consumables: digestion tubes, eluents, lamps and electrode membranes all have a lead time, and a laboratory that runs out of them loses more days than it loses to instrument drift. The second is bench time: a dedicated COD analyser with its own heating block removes a queue from the spectrophotometer, which is often the real bottleneck in a busy water laboratory.
How to plan the workflow
Start with the reporting list, then map each parameter to sampling, preservation, preparation, measurement and quality control. Water sources can change from clear drinking water to high load wastewater, so the same instrument list should not be assumed to fit every matrix.
For an international quotation, include the sample source, target range, daily workload, required standards, power supply and service location. This gives the supplier enough context to propose a practical combination of electrochemistry, spectroscopy, ion chromatography, elemental analysis and sample preparation.
Questions for a global project
- Which parameters are required by the local permit or customer specification?
- Which samples need digestion, filtration, dilution or preservation?
- Who will provide installation, training and ongoing verification?
Selection checklist: what to confirm before an inquiry
- Sample matrix
- Drinking water, surface water, groundwater and treated wastewater.
- Target parameters
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- Anions and cations
- Trace metals
- pH, conductivity and dissolved oxygen
- Absorbance-based parameters
- Method and conditions
- Reference methods differ by country and by regulator. Confirm the current standard, the reporting limit and the sample-preparation steps before selecting an instrument.
- Suggested configuration
- Ion chromatography for ionic composition, atomic absorption for trace metals, electrochemical meters for pH, conductivity and dissolved oxygen, and UV-Vis for absorbance-based parameters.
- Limitations
- Detection limits, matrix effects and sample preparation must be verified in your laboratory. This page is selection guidance, not a validated method.
Questions we are asked about this workflow.
Short answers; send the details of your method for a definite reply.
Do I need an ion chromatograph, or is titration enough?
Titration answers sum parameters such as alkalinity, hardness or chloride. It cannot separate individual anions. If the report has to list nitrate, sulphate and fluoride separately, ion chromatography is the shorter route.
Can one instrument cover pH, conductivity and dissolved oxygen?
Yes. Multi-parameter meters such as the P9 Series carry several electrodes and switch between them, which is usually cheaper than three instruments and easier to calibrate on a routine schedule.
How quickly must a sample be analysed?
Holding times are set by the method you report against and differ by parameter and preservation. Fix the sampling and transport routine first, then choose instruments that fit inside that window.
Is a colorimeter enough for COD?
For a single fixed-wavelength parameter, yes. As soon as the laboratory adds nutrients, colour or method development, a spectrophotometer with a wider wavelength range is the better long-term purchase.
Can the same benchtop meter serve drinking water and wastewater?
Yes, provided the calibration and electrode care suit the dirtiest sample on the bench. Wastewater work usually needs more frequent cleaning and a second electrode set.
What decides between flame and graphite furnace AAS?
The concentration you must report. Flame covers mg/L to sub-mg/L; trace work in the µg/L range needs the graphite furnace, which also brings a different level of operator training.
Let’s talk about your application
Discuss this application with our team.
Send your matrix, target parameters and reference method for a configuration review.