The orange juice market is huge. 聽Unfortunately some processors try to cut corners by extending the juice with sugar, pulpwash and water. 聽But the ruse can be detected by some clever science. 聽Oxygen in nature occurs as two possible isotopes, O-16 and O-18, which differ slightly in mass. 聽The natural abundance of O-18 is only about 0.2%, but it is more abundant in water in growing plants because the heavier isotope is less likely to evaporate. 聽So a juice diluted with water from non-biological sources will have a different isotope distribution and an instrument called a mass spectrometer can detect this. 聽The authorities have already used this method to put the squeeze on some OJ fraud artists.
