The ninhydrin reaction, one of the most important method of detecting amino acids, both technically and historically, has been conventionally used to detect their microgram amounts. When amino acids with a free alpha amino groups are treated with an excess of ninhydrin, they yield a purple colored product.
Update January 19: Amazon has increased the monthly price of Amazon Prime from $10.99 to $12.99 for those who opt for the month-to-month plan. However, the annual price remains untouched at $99 per year, which makes it the better option for avid Amazon shoppers.
Posted Nov 6, 2012 by Sarah Perez (@sarahintampa) Amazon is now offering users a monthly option for its Amazon Prime service, priced at $7.99 per month, as an alternative to the $79/yearly subscription. Itâs the same service as before, offering free two-day shipping, access to a free book monthly from the Amazon Lending Library for Kindle, instant streaming of movies and TV from Amazonâs Prime Instant Videos, and more.