Based on the low-field NMR, 1H NMR was used to establish the standard curve method, internal standard method, and external standard method for the rapid determination of alcohol content in Baijiu, beer, wine, and kirsch. The limits of detection and quantification were 0.08% (volume fraction) and 0.26% (volume fraction), respectively. Good linearity was observed in the alcohol content range of 0.5%-80% (volume fraction), with correlation coefficient R2 of the standard curve method, the external standard method, and the internal standard method being 0.996 1, 0.996 1, and 0.999 5, respectively. The precisions (relative standard deviation, RSD) of the three methods were less than 5%. The methods had good reproducibility and accurate results. The spiked recoveries of the standard curve method, the external standard method, and the internal standard method were 88.1%-97.81%, 84.61%-107.36%, and 81.83%-111.91%, respectively. It could be seen that the linearity, reproducibility and recovery of the methods met the requirements of accurate quantification. The errors between the methods of this study and the digital densimeter method of GB 5009.225—2016 were within ±5%, which met the requirements of feasibility comparative analysis and verification. Compared to the national standard method, the methods of this study had the advantages of simpler sample pretreatments, less sample usage (only 500 μL), and short test times (less than 5 min). Compared with the high-field NMR spectrum, the low-field NMR has the advantages of small volume, light weight and easy movement. It is suitable for the rapid and large-scale determination of alcohol content in alcoholic beverages.
[1] 刘宏欣, 张军, 黄富荣, 等.近红外光谱法快速测定啤酒的主要品质参数[J].光谱学与光谱分析, 2008, 28(2):313-316.
LIU H X, ZHANG J, HUANG F R, et al.Investigation on the quality indicators of beers using NIR[J].Spectroscopy and Spectral Analysis, 2008, 28(2):313-316.
[2] 李东军, 马伯荣, 胡兴美, 等.影响浓香型白酒总酸总酯变化的主要因素[J].酿酒, 2021, 48(3):130-131.
LI D J, MA B R, HU X M, et al.Main factors affecting the changes of total acids and esters in Luzhou-flavor liquor[J].Liquor Making, 2021, 48(3):130-131.
[3] 刘恩满, 李雪玉, 宗绪岩, 等.基于核磁共振氢谱技术建立白酒乙醇浓度检测方法[J].食品与发酵工业, 2021, 47(12):231-235.
LIU E M, LI X Y, ZONG X Y, et al.Detection of alcohol content in Chinese Baijiu based on 1H nuclear magnetic resonance spectrum[J].Food and Fermentation Industries, 2021, 47(12):231-235.
[4] 符郁馥, 刘冬妮, 周玉玲, 等.密度瓶法测定糯米酒中酒精度的不确定度评定[J].食品安全质量检测学报, 2019, 10(14):4 726-4 729.
FU Y F, LIU D N, ZHOU Y L, et al.Uncertainty evaluation for determination of alcohol degree in glutinous rice wine by pycnometer method[J].Journal of Food Safety & Quality, 2019, 10(14):4 726-4 729.
[5] 王秋瑾, 章平.白酒中乙醇含量检测方法的研究进展[J].现代食品, 2020(5):14-17.
WANG Q J, ZHANG P.Advance of ethanol content detection methods in liquor[J].Modern Food, 2020(5):14-17.
[6] 王超, 石利影, 刘楚楚, 等.不含糖露酒酒精度检测方法的探讨[J].酿酒, 2017, 44(6):73-74.
WANG C, SHI L Y, LIU C C, et al.Discussion on methods for the alcohol degree detection in sugar-free liqueur[J].Liquor Making, 2017, 44(6):73-74.
[7] 胡徽祥. 近红外光谱法快速测定调味料酒中的酒精度[J].现代食品, 2019(8):138-143.
HU H X.Rapid determination of condiment liquor by near-infrared spectroscopy alcohol quality[J].Modern Food, 2019(8):138-143.
[8] 樊双喜, 钟其顶, 李国辉, 等.近红外光谱法快速检测黄酒的酒精度、总糖和总酸[J].中国酿造, 2015, 34(2):135-138.
FAN S X, ZHONG Q D, LI G H, et al.Rapid determination of alcohol content, total sugar and total acid in Chinese rice wine by near-infrared spectroscopy[J].China Brewing, 2015, 34(2):135-138.
[9] PATZ C D, BLIEKE A, RISTOW R, et al.Application of FT-MIR spectrometry in wine analysis[J].Analytica Chimica Acta, 2004, 513(1):81-89.
[10] 祁慧雪. 核磁共振技术在化学物质定量分析中的应用[J].广东化工, 2012, 39(6):121;49.
QI H X.The Application of nuclear magnetic resonance technology in quantitative analysis of chemicals[J].Guangdong Chemical Industry, 2012, 39(6):121;49.
[11] CAO R G, NONAKA A, KOMURA F, et al.Application of diffusion ordered-1H-nuclear magnetic resonance spectroscopy to quantify sucrose in beverages[J].Food Chemistry, 2015, 171:8-12.
[12] 栾晓菲, 沈桂平, 郑彦婕, 等.基于核磁共振技术结合多元统计分析的啤酒化学组分定量与品牌鉴别[J].酿酒科技, 2016(5):48-53.
LUAN X F, SHEN G P, ZHENG Y J, et al.Compositional quantitation and brand identification of beer via NMR approach combined with multivariate statistical analysis[J].Liquor-Making Science & Technology, 2016(5):48-53.
[13] KUBALLA T, BRUNNER T S, THONGPANCHANG T, et al.Application of NMR for authentication of honey, beer and spices[J].Current Opinion in Food Science,2018,19:57-62.
[14] GODELMANN R, KOST C, PATZ C D, et al.Quantitation of compounds in wine using 1H NMR spectroscopy:Description of the method and collaborative study[J].Journal of AOAC International, 2019, 99(5):1 295-1 304.
[15] 吉鑫, 樊双喜, 李宜聪, 等.白酒中有机酸和醛类的偏最小二乘回归法定量分析模型[J].食品与发酵工业, 2020, 46(14):204-210;215.
JI X, FAN S X, LI Y C, et al.Quantitative analysis of organic acids and aldehydes in Baijiu via PLSR model[J].Food and Fermentation Industries, 2020, 46(14):204-210;215.
[16] 刘敏. 低场核磁共振技术(LF-NMR)在酿造酒品质检测中的应用[D].上海:上海理工大学, 2014.
LIU M.Assessment of brewing wine quality by LF-NMR[D].Shanghai:University of Shanghai for Science & Technology, 2014.
[17] 李刚, 张松, 高碧霞, 等.核磁共振波谱法分析代县黄酒成分及酒龄[J].化学分析计量, 2021, 30(8):28-33.
LI G, ZHANG S, GAO B X, et al.Analysis of components of Daixian wine based on 1H NMR technology and confirmation of wine ages[J].Chemical Analysis and Meterage, 2021, 30(8):28-33.
[18] 万相勇, 徐雪晶, 徐英杰, 等.定量核磁共振技术的测试流程[J].山东化工, 2020, 49(10):141-142.
WAN X Y, XU X J, XU Y J, et al.The study of testing process on quantitative nuclear magnetic resonance[J].Shandong Chemical Industry, 2020, 49(10):141-142.
[19] 徐雪晶, 万向勇, 赵锦漪, 等.氢核磁共振定量法初探[J].广东化工, 2020, 47(4):104;87.
XU X J, WAN X Y, ZHAO J Y, et al.The study on quantitative hydrogen nuclear magnetic resonance[J].Guangdong Chemical Industry, 2020, 47(4):104;87.
[20] 冯翠萍, 刘一诺, 樊双喜, 等.核磁共振磷谱法测定乳制品中的酪蛋白含量[J].食品科学, 2021, 42(4):221-226.
FENG C P, LIU Y N, FAN S X, et al.Determination of casein content in dairy products by 31P nuclear magnetic resonance[J].Food Science, 2021, 42(4):221-226.
[21] SCHOENBERGER T, MONAKHOVA Y B, LACHENMEIER D W, et al.Guide to NMR method development and validation-Part I:Identification and quantification[J].Eurolab Technical Report, 2014.DOI:10.13140/RG.2.1.1244.3689.