Hamilton Calibration Solutions (DuraCal pH and ORP Buffers and Conductivity Standards)

Hamilton DuraCal pH and ORP buffer solutions and conductivity standards are certified reference solutions for the field calibration of process and laboratory sensors. The pH buffers are traceable to NIST (USA) and PTB (Germany) through closed-loop traceability, and the conductivity standards are certified with DFM. As one of Hamilton’s distributors in Turkey, Mikron Proses (Üsküdar, Istanbul) supplies calibration solutions together with Hamilton sensors and provides application consulting on their selection.

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The complete value tables with order codes are on the DuraCal pH buffer solutions page. The sensors to be calibrated are described in Hamilton pH and ORP process sensors, the Hamilton conductivity sensors page and the bioprocess pH sensors page.

pH and ORP buffers: closed-loop traceability

The value of a DuraCal pH buffer comes from Hamilton’s closed-loop approach. Top-down, the buffer value is determined against secondary reference solutions that are compared against primary solutions from NIST or PTB. Bottom-up, a representative number of samples from every production lot is verified again by an independent DAkkS laboratory, and every production batch receives its own DAkkS calibration certificate.

The pH values run from 1.09 to 12.00. Accuracy is up to ±0.01 pH at pH 4.01 and 7.00 and ±0.02 pH for most other values. Stability is up to 60 months after manufacturing. For three-point calibration, 3 x 500 mL sets with pH 4.01 / 7.00 / 10.01 (REF 238924) or pH 4.01 / 7.00 / 9.21 (REF 238922) are available. For ORP (redox) measurement there are two buffers, 271 mV and 475 mV, with ±5 mV accuracy and 24 months stability.

The bottle has an integrated calibration compartment: you squeeze the bottle to fill the compartment, calibrate, and empty the compartment, so the remaining solution stays closed and uncontaminated. Only about 15 mL of buffer is used per calibration.

Conductivity standards: patented low-range stability

A conductivity standard is not a buffer, so for low values CO2 absorption or contamination can easily disturb the measurement. Hamilton states that it is the first manufacturer to offer patented standards of 1.3 and 5 µS/cm with a certified accuracy of ±1%; the determination procedure was developed in collaboration with DFM, the Danish institute for fundamental metrology, and confirmed by comparison measurements with PTB.

The range covers 1.3 µS/cm to 100 mS/cm. The 1.3 µS/cm standard is stable for 12 months and the other values for up to 36 months, depending on value and bottle. A bottle may stay open for a total of 60 minutes. For pure water background, see the pure water conductivity and USP 645 guide.

Compliance and use

The values are verified in ISO 17025 accredited laboratories (DAkkS and DANAK), and marked items in the catalog are ISO 17034 certified reference materials. These products are used where traceable calibration records are needed, for example in pharmaceutical, biopharma, food and beverage production.

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Which pH, ORP and conductivity values you need depends on the sensor type, the calibration frequency and your regulatory requirements. Tell us about your sensors and we will define the right solution set together.