How can DNA purity be checked? (original title "PROTOCOLS") - (Feb/11/2015 )

How can the purity of extracted DNA be checked.

OK... this is obviously a homework question that 2 minutes worth of google search will tell you... No need to post 6 times to ask the question. Moved to homework and the rest deleted. The title also isn't helpful as you aren't actually asking for a protocol (step by step instructions), you are asking for a technique (how). bob.

How do you think? Homework works like this: ask a question and show that you have put in some effort to find the answer and then we can expand and/or correct any misconceptions. This helps you learn as it makes you think, rather than just being spoon-fed answers.