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.
Amazon Prime membership costs $99 per year (or about $8.25 per month), but also includes unlimited, free two-day shipping on many items. You also get access to the company's growing selection of streaming TV shows and movies. Hulu Plus costs $7.99 per month or $95.88 per year.etflix subscriptions currently cost $7.99 per month, but that price will rise by $1 or $2 for new members later this quarter. Existing members will keep their current price for a generous period of time.