Affinity Thermoprecipitation. In the above examples, precipitation is achieved either by altering the pH or by adding a chelating agent. However, affinity thermoprecipitation, using polymers which undergo temperature dependent phase transition has also been used for separation and purification. Following are some examples (i) trypsin could be separated from a mixture of trypsin and chymotrypsin by changing temperature, (ii) lactate dehydrogenase (LDH) could be separated from porcine muscle extract, using Eudragit-Cibacron Blue, which was soluble at room temperature and precipitated at 40°C in the presence of 50mM ca²⁺, (iii) separation of oligonucleotides like (dA)₈ from a mixture of (dA)₄, dT (dA)₃ and (dA)₈ was also achieved by using conjugation with poly N-isopropylacrylamide (PNIPAM), which is thermoresponding.