Economically Motivated Adulteration of Lemon Juice: Cavity Ring Down Spectroscopy in Comparison with Isotope Ratio Mass Spectrometry: Round-Robin Study

• Published in: Journal of AOAC International 2019-09, Vol.102 (5), p.1544-1551
• Main Authors: Mantha, Madhavi, Kubachka, Kevin M, Urban, John R, Dasenbrock, Catherine O, Chernyshev, Anatoly, Mark, William A, France, Christine, Chartrand, Michelle, Hache, Jonathan, Decoeur, Sylvain, Qi, Haiping
• Format: Article
• Language: English
• Subjects: Canada; Carbon Isotopes; Citric Acid - analysis; Citrus - chemistry; Food Contamination - analysis; Fruit and Vegetable Juices - analysis; Mass Spectrometry - methods; New Zealand; United States
• ISSN: 1060-3271; 1944-7922
• DOI: 10.1093/jaoac/102.5.1544

Economically motivated adulteration (EMA) of foods has become an increasing concern in recent years, with lemon juice as a popular target. In this work, an optimized preparation procedure for the isolation of citric acid from lemon juice was validated using elemental analyzer-isotope ratio MS (EA-IRMS) to detect adulteration with exogenous citric acid. Additionally, 69 imported lemon juice samples were evaluated using combustion module-cavity ring down spectrometry (CM-CRDS) and compared with the well-established EA-IRMS. Equivalency of CM-CRDS to EA-IRMS was further demonstrated by conducting a round-robin study involving eight laboratories throughout the United States, Canada, and New Zealand. Overall, the results obtained for CM-CRDS were statistically indistinguishable from the results obtained using EA-IRMS for EMA lemon juice analysis. Therefore, CM-CRDS is a viable option for this application. The CM-CRDS instrumentation is easy to operate, robust, and provides δ C values comparable to EA-IRMS for citrate analysis. Through a multi-laboratory exercise, CM-CRDS was shown to be an alternative to EA-IRMS in the detection of economic adulteration of lemon juice.