I just wanted to provide the link to what Enrique was just suggesting:

http://nlp.stanford.edu/sentiment/

You can also read the book chapter-

Alena Neviarouskaya, Helmut Prendinger, and Mitsuru Ishizuka. Recognition of Fine-grained Emotions from Text: An Approach Based on the Compositionality Principle. In: Modelling Machine Emotions for Realizing Intelligence: Foundations and Applications, T. Nishida, L. Jain, and C. Faucher (eds.), Springer Smart Innovation, Systems and Technologies (SIST), Vol. 1, pp. 179-207, 2010

Hi,

   first of all I would like to clear some ambiguities between sentiment analysis and emotion detection which is known as Affective Computing. Traditional sentiment analysis approaches do not detect the emotions from the text rather only rank them as positive and negative. Affective computing is the area of research which deals with the detection of emotions from the text which normally used are six i.e. Anger, Disgust, Fear, Happiness, Sadness and Surprise. For more details on emotions read the following article.

Hovy, E. H. What are Sentiment, Affect, and Emotion? Applying the Methodology of Michael Zock to Sentiment Analysis Language Production, Cognition, and the Lexicon, Springer, 2015, 13-24

Yes there are number of algorithms for detecting emotions from the text like machine learning and dictionary based algorithms. Following are the some articles for detecting emotions from text.

Gievska, S.; Koroveshovski, K. & Chavdarova, T. A Hybrid Approach for Emotion Detection in Support of Affective Interaction Data Mining Workshop (ICDMW), 2014 IEEE International Conference on, 2014, 352-359

Strapparava, C. & Mihalcea, R. Learning to identify emotions in text Proceedings of the 2008 ACM symposium on Applied computing, 2008, 1556-1560

Hope this will help.