Cabañero Ana I, San-Hipólito Tamar, Rupérez Mercedes
Laboratorio Arbitral Agroalimentario. Ministerio de Agricultura, Pesca y Alimentación, Crta. Coruña Km 10.700, 28023 Madrid. Spain.
Rapid Commun Mass Spectrom. 2007;21(20):3323-8. doi: 10.1002/rcm.3212.
A new procedure for the determination of carbon dioxide (CO(2)) (13)C/(12)C isotope ratios, using direct injection into a GasBench/isotope ratio mass spectrometry (GasBench/IRMS) system, has been developed to improve isotopic methods devoted to the study of the authenticity of sparkling drinks. Thirty-nine commercial sparkling drink samples from various origins were analyzed. Values of delta(13)C(cava) ranged from -20.30 per thousand to -23.63 per thousand, when C3 sugar addition was performed for a second alcoholic fermentation. Values of delta(13)C(water) ranged from -5.59 per thousand to -6.87 per thousand in the case of naturally carbonated water or water fortified with gas from the spring, and delta(13)C(water) ranged from -29.36 per thousand to -42.09 per thousand when industrial CO(2) was added. It has been demonstrated that the addition of C4 sugar to semi-sparkling wine (aguja) and industrial CO(2) addition to sparkling wine (cava) or water can be detected. The new procedure has advantages over existing methods in terms of analysis time and sample treatment. In addition, it is the first isotopic method developed that allows (13)C/(12)C determination directly from a liquid sample without previous CO(2) extraction. No significant isotopic fractionation was observed nor any influence by secondary compounds present in the liquid phase.
一种用于测定二氧化碳（CO₂）¹³C/¹²C同位素比值的新方法已经开发出来，该方法通过直接注入GasBench/同位素比值质谱仪（GasBench/IRMS）系统，以改进用于研究气泡饮料真实性的同位素方法。分析了39个来自不同产地的市售气泡饮料样品。当在二次酒精发酵中添加C₃糖时，δ¹³C（卡瓦酒）值范围为-20.30‰至-23.63‰。对于天然碳酸水或添加了泉水气体的水，δ¹³C（水）值范围为-5.59‰至-6.87‰，而添加工业CO₂时，δ¹³C（水）值范围为-29.36‰至-42.09‰。已证明可以检测到向半气泡葡萄酒（阿瓜亚）中添加C₄糖以及向气泡葡萄酒（卡瓦酒）或水中添加工业CO₂的情况。新方法在分析时间和样品处理方面比现有方法具有优势。此外，这是开发的第一种同位素方法，能够直接从液体样品中测定¹³C/¹²C，而无需事先提取CO₂。未观察到明显的同位素分馏现象，也未受液相中存在的次生化合物的影响。
