FAQs - Sample measurements with the PeakSeeker instruments

What is the purpose of the PeakSeeker's supplied sample compartment?

A sample compartment that accepts the probe shaft ensures eye safety when the laser is on and blocks potential background noise from room light. When the sample is either a liquid or a powder in a small bottle or vial, the sample holder can be used. The combination of electronic laser control and the sample compartment makes it so the user is not exposed to the laser light. The laser is off until a scan is activated through the software. The cover of the sample compartment blocks the laser light. Placing a sample in the compartment and setting the cover in place, prevents user exposure to the laser beam.

What is the purpose of the measurement caps for the end of the PeakSeeker probe?

Each instrument is supplied with measurement caps for the end of the probe shaft to aid with placing the focus of the laser beam onto the sample. The default focal point is 8 mm out from the end of the sample tube. The spot size is roughly 100 μm in diameter at the focal point.

Which cap is used to measure a solid sample?

The cap labeled S is long enough that the spot is focused on the surface of soft solids when the cap is pressed against the surface. Some solids may require a probe holder with vertical translation to correctly focus the spot on the surface.

Which cap is used to measure a liquid sample?

For liquid inside containers with walls less than 2 mm thick, the cap labeled L is short enough that the focal point will be inside the container.

For most solids and liquids, the measurement cap is placed in contact with the sample or container to set the focus. Exceptions are described below.

How do I measure a powder or turbid liquid sample?

For turbid liquids, powders or solids inside a container, the probe with L cap may have to be withdrawn slightly (1-3 mm) from contact with the container to place the probe focal point at an optimum position within the highly scattering sample medium. This will improve the scan results.