Purification

Unfortunately, none of the fractions you collected contain your desired product alone.

Examine the TLC plates again for evidence of this:

UV light

iodine plate 1

The photo shows the first thin layer chromatography plate, stained off white. The spots visible in the UV visualized photo have been circled in pencil. The spots closer to the spotting line in lanes TP, 1, 2, and 3 are stained dark brown in this photo. A ruler also visible in the photo, with its 0 cm marking aligned with the spotting line, reveals that these dark brown spots are approximately 0.5 cm from the spotting line. The spots farther down the plate in lanes 1, 2, and 3 are strained a lighter brown in this photo. We see from the ruler that these lighter spots appear approximately 2.5 cm from the spotting line.

iodine plate 2

The photo shows the second thin layer chromatography plate, stained off white. The spots visible in the UV visualized photo have been circled in pencil. The spots closer to the spotting line in lanes TP, 4, 5, and 6 are stained dark brown in this photo. A ruler also visible in the photo, with its 0 cm marking aligned with the spotting line, reveals that these dark brown spots are approximately 0.6 cm from the spotting line. The spot farther down the plate in lane 4 is colorless in this photo. We see from the ruler that these lighter spots appear approximately 2.8 cm from the spotting line.

Think about why collecting large fractions leads to a mixture of the main product with the triphenylphosphine oxide side product. If you aren't sure, ask your GSI!

Re-load your mixture onto the top of the column.

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