Entry #6 - Blood Identification

This course stank. Well, I quite enjoyed it, but it seriously stank.


I can't tell which was better/worse, the sheep heart experiment, or this one.

It's seriously, seriously that bad, especially when you mixed hydrogen peroxide with cockle blood. When you do it in large quantities, and proceed to dump it down the sink, the entire bench stinks with cockle blood + hydrogen peroxide, and it smells...like blood.

Haha, yeah, that's obvious.

But really, usually blood is bearable, but it was really awful this time. I felt like I was drowning in a sea of blood (and the scent of iron!) and it just makes you want to retch. The only good part of this was that the experiment was very fun.

Basically, we were given 6 samples, and were told to predict whether blood was in the sample or not, before proceeding to test our hypothesis with hydrogen peroxide. Hydrogen peroxide reacts with the catalasts that are found in cells; thus, Samples 4, 5 and 6 are found to contain catalasts, since they started to bubble (Sample 4 especially - urghhhh).

Next we had to add luminol to the samples. Apparently, the iron in the blood catalyses the chemical reactions and leads to a form of glowing, and only Sample 4 glowed. After which, we added the Kastle-Meyer Reagent (reduced phenolphthalein in alkaline solution, in the presence of zinc). Oxidation with haemoglovin and hydrogen peroxide will turn the Kastle-Meyer Reagent pink; thus, if the sample turns pink, well, it contains blood.

And since Sample 4 turns pink, it contains blood. Cockle blood.

This entire experiment was fun, but it also reminds me why I dislike Chem. Don't you just dislike it when you want to know what happens but you don't? Chem gives me that sort of feeling. Looking at what's actually happening - all the chemical reactions and stuff - I can't help but feel frustrated. Why do these chemical reactions occur? What determines that these types of chemical reactions occur? What actually happens, on the atomic scale, when the chemical reactions occur?

LSS Chem didn't answer these questions - which was probably why I hated Chem then. It was just so irritating; I'm the sort of person who, unless I understand everything, don't understand a single thing, so I was more or less completely clueless throughout the entire semester.

Joy.