Temperature Monitoring in Analysis Laboratories

Comastri Davide recently concluded the first in a series of webinars for industry specialists on October 7th. Specifically, the first webinar, led by Dr. Stefania Accorsi, explored temperature monitoring in analysis laboratories in the food and pharmaceutical sectors.

Drugs and food are highly sensitive to temperature variations; consider the simple need to store medicines and food products at low temperatures to prevent spoilage. However, adequate temperature monitoring in laboratories in the food and pharmaceutical sectors is also important for other reasons.

Environmental Conditions and Reference Standards

From a regulatory point of view, the guidelines to follow for the minimum level of procedural, hygiene, quality and traceability standards of results are:

• ISO 9001 for Quality Management
• ISO/IEC 17025 for Requirements for Testing and Calibration Laboratories
• ISO 15189 for Requirements for Medical Laboratories

These guidelines emphasize the importance of monitoring and documenting environmental parameters in the temperature measurement process. The reliability, authenticity, replicability, and traceability of the measured parameters can only be guaranteed under uniform conditions and taking into account external influencing factors.

To ensure a high level of product safety, it is also important to monitor:

• Functional test temperatures to evaluate product performance under extreme conditions
• Reaction temperatures to monitor any chemical reactions (for example, we refer to synthesis, decomposition, substitution and metathesis.)
• Storage temperatures for maintaining certain characteristics (for example, in the food sector we refer to the slowing down of bacterial proliferation and therefore the possible alteration of the food itself)

Temperature Measuring Instruments

Measuring instruments achieve maximum precision only if certain parameters, such as ambient temperature, electromagnetic interference, humidity, and air pressure, remain constant: for example, the temperature in measurement laboratories is normally 20°C.

We can define temperature as the heat transfer potential between two bodies: this means that when two bodies are brought into contact, a heat flow is generated from the hotter to the colder until both reach the same temperature. A thermometer is the instrument used to calculate the temperature variation with a body; to do this, however, it is necessary to identify a standard temperature scale.

The Temperature Scale

Unlike other units of measurement, such as the meter for length, temperature is determined based on the physical properties of certain materials: in everyday life, we know that 100 degrees Celsius is the temperature at which water boils, and 0 degrees Celsius is the temperature at which it freezes. The international standard unit of measurement for temperature, however, is the degree Kelvin, and to calibrate a reference thermometer, fixed points are used whose temperatures have been established with extremely precise scientific experiments (for example, the melting point of materials like aluminum or gold).

What are the tools for measuring temperature in laboratories?

The commercially available instruments for measuring temperature that can be used in the food and pharmaceutical sectors are:

• Resistance Temperature Detectors (RTDs), which have a wire or film of material whose electrical resistance changes as the temperature varies.
• Thermistors (NTC, Negative Temperature Coefficient), composed of a small bead of semiconductor oxides whose resistance increases rapidly as the temperature decreases
• Resistance thermometers/Thermocouples, a sensor that generates a voltage in an electrical conductor when the temperature is different at the two ends of a cable

Regardless of the instrument used, temperature monitoring occurs in the following ways:

• Sample control measurement, which is low cost but provides a small amount of data
• Data Logger, ensures constant recording of data that must then be evaluated manually (therefore, a wait is required between recording and data analysis)
• Real Time Monitoring, ensures constant data collection and automatic analysis, but requires a WLAN network or Internet access

For further information on the Tools available on Comastri Distribution you can visit the page relating to Temperature Measuring Instruments, or go to the Contact page to find out about upcoming Webinars.