Sterilisation of an analyte sensor component

A method of sterilising a sensor component for use in a system for measuring the concentration of one or more analytes in fluid in a fluid line, the method comprising:

• providing a sensor component comprising one or more ports providing fluid connection to a cavity and configured to expose one or more sensing elements in a dry state to the fluid in the fluid line, the one or more sensing elements having an optical property that varies with the concentration of the one or more analytes in the fluid;
• and
• a connector configured to connect to one or more optical waveguides, the sensor component being configured to transmit light between the one or more optical waveguides and the one or more sensing elements;
• the method further comprising:
• connecting tubing to the one or more ports;
• introducing a gaseous sterilising agent into the cavity via the one or more ports providing fluid connection to the cavity, wherein:
• i) the one or more sensing elements are exposed to the cavity and are thereby sterilised by the gaseous sterilising agent, and ii) introducing the gaseous sterilising agent comprises flowing the gaseous sterilising agent through the tubing;
• hydrating the one or more sensing elements by replacing the gaseous sterilising agent with a sterile liquid via the one or more ports, wherein replacing the gaseous sterilising agent with the sterile liquid comprises flowing the sterile liquid through the tubing;
• and
• sealing the one or more ports, wherein sealing the one or more ports comprises sealing the tubing, and cutting the tubing outside the position where the tubing is sealed such that a sealed section of the tubing remains connected to the one or more ports.