Investigation of various shellac grades: additional analysis for identity.
BACKGROUND
A number of different grades of shellac are commercially available and most of them are known only as generic shellac and are not further differentiated. The investigated grades of shellac in this study are based on different insect strains, host trees, refining methods, and products from different suppliers.


METHODS
The Gardner/Iodine color values of alcoholic and aqueous solutions of the various shellac grades were measured. Glass transition temperatures and pK(a)-values were determined. To assess chemical differences in the tested shellac grades, MALDI-TOF analysis was performed.


RESULTS
Differences were found in color, T(G), and pK(a)-values and in the mass spectra by MALDI-TOF analysis.


CONCLUSIONS
The results indicate that these methods can facilitate the determination of identity and are quality control parameters for shellac.
Buch
Karl
K
Department of Pharmaceutical Technology and Biopharmaceutics, Johannes Gutenberg-University, Mainz, Germany.
Penning
Manfred
M
Wächtersbach
Eva
E
Maskos
Michael
M
Langguth
Peter
P
D000818:Animals; D003116:Color; D003692:Delayed-Action Preparations; D005079:Excipients / Q000737:chemistry* / Q000302:isolation & purification; D007313:Insecta; D011786:Quality Control; D012116:Resins, Plant / Q000737:chemistry* / Q000302:isolation & purification; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D044366:Transition Temperature
D003692:Delayed-Action Preparations; D005079:Excipients; D012116:Resins, Plant; C003934:shellac