Yes DrFilth, that is the highest one you can buy [to my knowledge] unless you mix your own juices. On most [e-cig] forums there are a fair few people who buy their own nicotine and mix it to the desired strength.
LG, from Wiki,
The LD50 of nicotine is 50 mg/kg for rats and 3 mg/kg for mice. 0.5-1.0 mg/kg can be a lethal dosage for adult humans, and 0.1 mg/kg for children.[
From the same source, one paragraph on
"However the widely used human LD50 estimate of 0.5–1.0 mg/kg was questioned in a 2013 review, in light of several documented cases of humans surviving much higher doses; the 2013 review suggests that the lower limit causing fatal out-comes is 500–1000 mg of ingested nicotine, corresponding to an oral lD50 of 6.5–13 mg/kg"
The original LD50 is outdated, as later studies have shown.
There has been quite a lot of work on tracing the amount of nicotine that gets into the bloodstream from a single cigarette though, and studies of various cases on non-fatal ingestion of nicotine suggest that the LD50 was very underestimated previously.
I was once a hardcore smoker. Now I'm a hardcore vaper :D .. I turned because of health issues. But still I can't cut myself from smoking. That's when I tried e cigs. Pretty good I must say. Actually referred to me by my friend. Said that I should get my starter kit here: http://www.bandmonline.co.uk/electronic-cigarette.html .. You know, e cigs does really help to quitting smoking.