by Police - Bureau of Police Research and Development

• Sample PreparationThe Indian Police Journal‣ Printouts were taken from Inkjet printers, HP Business Inkjet1000 & HP PhotoSmart C 3188. ‣ The sample was prepared by keeping constant RGB values inTable 1: Values of RGB (Red, Green, Blue) colour model in MS-Wordused for printing of documents on the same substrate of paperBilt copierInkjet Ink R G BCyan 0 255 255Magenta 255 0 255Yellow 255 255 0Krypton (Black) 0 0 0InstrumentationPlates were developed in a 20 cm x 20 cm CAMAG HPTLCchamber in the solvent system n-butanol: acetone: distilled water:ammonia = 25:25:5:17.5. Spots of samples were applied usingdisposable capillaries by keeping origin point at 1.5 cm. Afterapplication, spots were dried. The development distance was 100 mmfrom the origin (spotting point) of the plate and the migration time wasapproximately 35 minutes.To analyze the processed ink, a small piece of paper was dissolved in1,2 dichloroethane. TLC of processed ink extracts from both printers aluminum plates from Merck. TLC plates were activated in oven developed by saturating chambers for 20 min. But the best results wereobtained by using unsaturated chambers. After 35 min, plates wereremoved from the chamber. The spots were visualized by observationunder a 254 nm & 366 nm UV lamp CAMAG Reprostar of HPTLC.Densitometric evaluation with the TLC scanner 3 (CAMAG) was carriedout by absorbance measurement at UV 320 nm in the calibrationrange of 200 to 700 nm. Plate’s images were documented by use ofthe digistore2 documentation system (CAMAG) under illumination atUV 254 nm and UV 366 in absorbance mode. Data obtained wereprocessed with win CATS software version 1.4.2 (CAMAG). Spectralanalysis under visible and UV range has been done for all samples.January - March, 2013163