Used Laboratory Measurement Instruments for Sale

Laboratory measurement instruments is a broad category covering specialty bench instruments that measure physical, chemical, or environmental properties — but don't fit a single-technology category. It includes UV/Vis spectrophotometers, vacuum gauges (Pirani, Bayard-Alpert, capacitance manometers), strain gauge indicators and bridge amplifiers, particle counters, pH/conductivity/dissolved oxygen meters, melting point and boiling point systems, viscometers, synchro/resolver test sets, density meters, colorimeters, and similar specialty instruments used in research, QC labs, and industrial process measurement.

UV/Vis spectrophotometer calibration covers three parameters: wavelength accuracy (verified at known absorption peaks — didymium glass or holmium oxide filter standards), photometric accuracy (absorbance at multiple points against NIST-traceable neutral density standards), and stray light rejection. A calibrated deuterium/tungsten lamp set and wavelength drive accuracy determine whether the instrument holds calibration between services. Most Shimadzu UV-1800 and Agilent Cary 60 instruments maintain wavelength accuracy within ±0.3 nm over a 12-month interval under normal lab conditions.

The most common used vacuum gauges are Pirani thermal conductivity gauges (MKS 902, Leybold TR201) for rough vacuum (1 atm to 1 mTorr), capacitance manometers (MKS Baratron 626, 627, 628) for precise absolute pressure from 10 Torr down to 0.01 Torr regardless of gas type, and Bayard-Alpert ionization gauges for high vacuum below 10⁻³ Torr. Capacitance manometers are preferred wherever gas-type independence and accuracy matter — semiconductor process equipment almost universally uses them. Pirani gauges are gas-dependent and less accurate but inexpensive and robust for rough-vacuum monitoring.

A strain gauge indicator is a precision bridge amplifier that supplies excitation voltage to a strain gauge or load cell, measures the microvolt-level bridge output, and converts it to engineering units (strain in microstrain, force in pounds, pressure in PSI). The Vishay P3, Measurements Group 2310, and Micro-Measurements 7000 are common models. Key specifications are bridge excitation voltage (1.5 V to 10 V DC), input sensitivity (±50 mV full scale is typical), noise floor, and the number of simultaneously readable channels. For structural test, a multi-channel strain data acquisition system (Vishay 5100, HBM QuantumX) is more practical than individual indicators.

Request the most recent calibration certificate showing wavelength accuracy and photometric accuracy as-found values, not just the as-left pass. Wavelength drift greater than ±1 nm at 656 nm (Hα) on a unit calibrated less than 12 months ago suggests lamp aging or wavelength drive wear. Ask whether the deuterium lamp has been replaced — D2 lamps have a 2,000-hour rated life. Verify the scan speed and data interface work correctly. On double-beam instruments (Shimadzu UV-2600, Varian Cary 300), verify the reference beam detector response matches the sample detector within ±0.5% absorbance at a mid-range wavelength.

We calibrate common laboratory measurement instruments where NIST-traceable standards are available and the calibration is achievable on the bench — including vacuum gauges against known pressure standards, strain gauge indicators against precision resistance bridges, spectrophotometer wavelength accuracy against holmium oxide glass standards, and pH meters against certified buffer solutions. For highly specialized instruments requiring manufacturer-specific fixtures or reference standards not in our inventory, we will advise on accredited calibration lab options. Contact us with the specific instrument and required calibration scope.