Production of some of the PhP plates will be discontinued. This goes especially for the high resolution PhP-plates. There are still some in store, but If you think you will need further plates, we keep the reagents, so there is always possibility to produce extra plates. Please contact us by E-mail if you need extra plates
Question: The absorbance of 150 ul of my substrate at 620 was 2.4, slightly higher than the target range. Any suggestions on how to remedy?
Answer: High absorbances may be due to:
- Too much indicator. The problem you might run into by using too high indicator amount is that the reader sensitivity is decreased at high values. You can then either – add 10% more substrate without indicator (only peptone) – or use it as it is and hope for the best (use option ‘Substrate normalisation’ in the PhP software to mathematically reduce the values) – or make a new substrate
- Too high pH Solutions. Check that the pH does not exceed 8.5, and adjust it if it does.
Question: I have problems with evaporation of the media in the plates. I stack the plates into sets of 4 or 5 and lightly cover them on the sides with foil then put them in a box with a plastic container turned upside down over them together with a small container filled with water to create a moist environment. I however still see that some wells evaporated, mainly the ones closest to the sides and especially the no. 12 well of the first two and last two rows. What can I do to prevent this from happening?
Answer: Use a (plastic) box with lid (not too tight). In the bottom of the box, under the plates, put a moist paper towel.
Question: We have been reading our results at single time points ie. 7, 24 and 48 hours, but we are unable to construct a profile of mean values to produce one dendrogram. Instead, we are producing three dendrograms, one at each time. How can we combine the three readings to produce a dendrogram of mean values?
Answer: When you read plates you should use the same file name for all readings, i.e. at the first reading (7h) you select ‘First reading of data’ and give a new file name, and next times you read (24 and 48h) you select ‘second and other readings’ and select the same name as the first reading. After the last reading (or after all readings, if you want to look at data earlier) you select ‘Create PhP data after the last reading’ and save as normal biochemical fingerprints. If you have read data into separate files, you can always put together and edit the files with a file editor (e.g. Windows notepad, MS Word), but it is important that you keep the right format! The manual for the software shows what format to use (make a backup copy before, if something should go wrong). If you read data into Excel it is easy: just use Excel to produce mean values of all readings