The copper pots and jam challenge

We would like to invite you to participate in the Analytical Challenge, a series of puzzles to entertain and challenge our readers. This special "Analytical and Bioanalytical Chemistry "feature has established itself as a truly unique quiz series, with a new scientific puzzle published every other month. Readers can access the complete collection of published problems with their solutions on the ABC homepage at In the present challenge, copper and jellification is the topic. And please note that there is a prize to be won (a Springer book of your choice up to a value of [euro]75). Please read on...