... phases * Dichloromethane: acetone (9:1) * Chloroform: acetone: ammonia (9:9:2) * Propan-2-ol: chloroform: ammonia (9:9:2) The plates were exposed to ammonia vapour before using fluorescence quenching as a detection method. From the plates it can be seen that phenbarbitone (PB) and barbitone are the barbiturates present in mixture A. See fig 1 (write on plates how you came to conclusion) IR analysis Mixture A and standards of different barbiturates were analysed by the IR spectrophotometer by radiation at wavelengths ranging from 500cm-1 to 4000cm-1. The IR spectra of Mixture A shows a 95.53% match with phenobarbitone and otherwise appears not to contain any other barbiturates. This could be because there is much more phenobarbitone than barbitone in the mixture but looking at the TLC plates this does appear to be the case. The spots of barbitone and phenobarbitone are similar in size. Another reason may be that the machine had not been properly cleaned before use. This is unlikely ...

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