Detection of adulteration of commercial honey samples by the 13C/12C isotopic ratio

It is very difficult to detect adulteration by conventional laboratory methods. However, differences in stable carbon isotope ratio (C-13/C-12 = parts per thousand), between honey and its protein fraction give a qualitative and quantitative indication of honey adulteration. Forty honey samples from Brazil and eight imported from Argentina, Canada and the USA, were analyzed to detect possible adulteration by gas chromatography/mass spectrometry. Honey was adulterated with sucrose solution and high fructose corn syrup (HFCS) to determine detection limits. The C-13/C-12 value for honey and its protein fraction should not differ more than 1parts per thousand for delta (6). The range of values found for bee-produced honey was -21.96parts per thousand to -30.47parts per thousand for C3 plants and -11.82parts per thousand to - 19.00parts per thousand for C4 plants (produced near cut sugar cane and not considered to be flower honey). For cane sugar it was -11.33parts per thousand to -11.78parts per thousand, and -9.70parts per thousand to -9.78parts per thousand for HFCS. Adulteration was found in six Brazilian honey samples. (C) 2003 Elsevier Ltd. All rights reserved.