FD&C Color Variation
Good morning all!
I am trying to determine an SOP for testing FD&C incoming raw colors to ensure that our FD&C blends will not have a visual variance related to the allowable variance on the certified color specification in our finished products. Can anyone recommend a procedure using a coloremeter for testing incoming FD&Cs? Specific L.A.B. values perhaps or methods to determine them? I have come up with a number of potential options but I would like it to be a tried and true method if possible. Perhaps someone can recommend a lab service that could test total color content? We have had trouble finding a lab that offers this service however.
Thank you for your time!
Hi,
Try contact Konica-Minolta, they have plenty of this gadgets.
Dye content can be determined using spectrophotometers where absorption of a solution of known concentration is recorded at a specifc wavelength (Different for different colours) and is calculated considering E1% of the dye at the specified wavelength (available on internet).
COA might also be mentioning subsidiary dye content and dye intermediates to establish the purity and safety of dyes. These can be done by thin layer chromatography.
Depending on the testing infrastructureI available, you can decide whether to conduct all the analyses in-house or follow a verification procedure where the approved vendor provides you a COA always and where you can conduct a test for total dye content for every supply ! In case it matches with the vendor's COA consider his COA values for the remaining tests. Simultaneously outsource the testing once to ISO 17025 labs for verification purposes.
Having spent a long career as an automotive coatings chemist where exact color matches a super critical when you have many plastic and metal parts coming from many sources and must match precisely I'd recommend that you look into an X-Rite (no affiliation) low level single angle spectrophotometer. Their website is: