Wagtech™ Potacheck

Photometers should be regularly cleaned to ensure that your instrument is reading correctly and is not affected by dust or water marks.

To clean a compact photometer, place a small amount of anti- static cleaning foam on to a lint free cloth and wipe the instrument.

For multiparameter photometers, you should clean several parts of your instrument. To clean, place a small amount of anti- static cleaning foam on to a lint free cloth and wipe the instrument.

1. Sample holder.
   The first image shows the surface around the sample holder, all visible marks on this area should be removed
2. Outside optics base plate.
   Turn the instrument over and undo the two screws on the base of the instrument, as demonstrated in the second image. Gently wipe the curved areas near the LEDs and the flat area on the opposite side.
3. Inside optics base plate
   Contamination on the inside of the base plate can migrate onto your calibration tubes leading to scratches which damage the standards. If marks cannot be removed from the base plate, a new base plate should be fitted.
   When refitting or replacing a base plate, you must ensure screws are tightened so that the standards are set are the correct height. Failure to do so can lead to compromised results.
   

Check standards are used to determine if an instrument is still within calibration.

Photometers work by sending light through the sample, check standards for these instruments are usually either Coloured Solutions or Neutral Density Filters (NDF). Both types have known and certified transmittance or absorbance values so they should give these values when read in a photometer. To make the checking process even simpler some instruments will convert these to a parameter such as chlorine and give the value mg/L. The ‘target’ value is on the certificate supplied with the set of Check Standards.

Kemio and sensor instrument check standards verify that the instrument correctly measures electric signals. As with electrochemical sensors in samples, the instrument applies a voltage to the check standard and measures the resulting current. Check standards include verified resistors, which produce a consistent electric current. Kemio validates the measured current internally. Sensor instruments display the corresponding concentration value, which is compared manually to target values on the certificate supplied with the set of check standards. Check standard kits come with four standards to test across the measurement range.