Hamilton DuraCal pH Buffer, ORP and Conductivity Calibration Solutions

Hamilton DuraCal buffer solutions calibrate process and laboratory pH, ORP and conductivity sensors with certified, traceable reference solutions. The pH buffers are traceable to the primary standards of NIST (USA) and PTB (Germany) through a closed-loop chain and carry a DAkkS calibration certificate for every production batch. Hamilton states a pH stability of up to five years and an accuracy of up to ±0.01 pH. As one of Hamilton’s distributors in Turkey, Mikron Proses (Üsküdar, Istanbul) supplies DuraCal pH, ORP and conductivity solutions and provides application consulting on calibration.

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The sensors these solutions calibrate are described in Hamilton pH and ORP process sensors, the EasyFerm Plus, EasyFerm Bio and OneFerm pH sensors, Hamilton Conducell conductivity sensors and the Arc peripherals and ArcAir page. A shorter overview of the whole range is on the calibration solutions page.

pH buffers and traceability

Hamilton works with circular, closed-loop traceability. Top-down, the buffer value is determined against secondary reference solutions that are themselves compared against primary solutions from PTB or NIST. Bottom-up, a representative number of samples from every production lot is verified by an independent DAkkS laboratory, which closes the loop.

The pH 4.01 / 7.00 / 10.01 set (REF 238924) is a three-buffer set for calibration at common pH levels; each liquid solution comes with a certificate and serves as a Certified Reference Material. The datasheet gives the accuracy and stability as ±0.01 pH for 24 months or ±0.02 pH for 60 months after the date of manufacturing, and a storage range of 5 to 35 °C.

Buffer	250 mL bottle (REF)	500 mL bottle (REF)	3 x 500 mL (REF)
pH 4.01	238317	238217	238917
pH 7.00	238318	238218	238918
pH 9.21	238319	238219	238919
pH 10.01	238321	238223	238923

The other pH values (1.09, 1.68, 2.00, 3.06, 5.00, 6.00, 8.00, 11.00 and 12.00) are available in 500 mL bottles. The pH 9.21 and 10.01 buffers are stable even when exposed to air.

ORP buffers

Value	Accuracy	Stability	Package (REF)
271 mV	±5 mV	24 months	500 mL (238228)
475 mV	±5 mV	24 months	250 mL (238322), 500 mL (238227)

Conductivity standards

Because a conductivity standard is not a buffer, absorption of CO2 or contamination shifts low values easily. 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 standards come with a certificate from DFM, the Danish Institute of Fundamental Metrology, and are developed in collaboration with it.

Value at 25 °C	Accuracy	Stability (months)	Package (REF)
1.3 µS/cm	±1%	12	250 mL glass bottle (238973)
5 µS/cm	±1%	36	250 mL glass bottle (238926)
15 µS/cm	±1%	36	250 mL glass bottle (238927)
84 µS/cm	±1%	18	500 mL Calpack bottle (238984)
100 µS/cm	±1%	36	250 mL glass bottle (238934)
147 µS/cm	±1%	18	500 mL Calpack bottle (238985)
706 µS/cm	±2%	36	250 mL glass bottle (238929)
1413 µS/cm	±1%	36 / 18	250 mL glass bottle (238928) / 500 mL Calpack bottle (238986)
12,880 µS/cm	±1%	18	500 mL Calpack bottle (238988)
100 mS/cm	±1%	36	250 mL glass bottle (238935)

Bottles may stay open for a total of 60 minutes. For background on pure water conductivity measurement under USP 645, see the pure water conductivity and USP 645 guide.

Electrolytes, storage and cleaning

For electrode care Hamilton also offers 3 M KCl storage and refill solution, the reference electrolytes Skylyte and Protelyte, and a cleaning solution set (REF 238290) for the pH glass and the diaphragm.

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