I believe that's why he started calling himself that.
In the show, his character is very intelligent and i believe has a Ph.D or masters in chemistry. That's why he was able to cook the best and purest meth anyone had ever seen. One of my all time favorite shows. Well worth checking out. He was a very square chemistry teacher who found out he had terminal cancer. He calculated how much money his family would need for college, the house, living etc. and set out to make that amount. He chose to do so by cooking meth, something that he described as 'basic chemistry.' Of course, things then got way out of control......