Rapid Detection of Ethyl Carbamate in Chinese Liquor

A recent study examined how to better detect ethyl carbamate, which is a byproduct that occurs naturally during the fermentation process of alcohol. This study, which was published in the journal Talanta, was conducted by a team of researchers at the Dalian Institute of Chemical Physics at the Chinese Academy of Sciences (1). In their study, the research team introduced a novel method that combines gas chromatography with photoionization-induced chemical ionization time-of-flight mass spectrometry (FastGC-PICI-TOFMS), enabling accurate, high-throughput EC analysis in under four minutes (1).

What is ethyl carbamate?

Ethyl carbamate is a process contaminant formed during the fermentation process of alcohol (1,2). It occurs at low levels in products like bread, soy sauce, beer, and wine, but can reach higher concentrations in distilled spirits made from sugar cane or stone fruits due to precursor compounds and high distillation temperatures (2). Ethyl carbamate is considered to be unsafe for human consumption because of its classification as a carcinogenic (1). As a result, current industry practices are putting forth great effort to minimize its presence in finished products.

What did the researchers test in their study?

The research team tested out their FastGC-PICI-TOFMS method to see if it could improve on traditional techniques and overcome some of the key limitations. Integrated in this method was a thermostatic FastGC column maintained at 150 °C for rapid EC separation, as well as a PICI-TOFMS system that eliminates the need for any pre-treatment of samples (1). The thermostatic column plays a critical role in removing matrix interferences, which can otherwise obscure or distort EC measurements, whereas the PICI source ensures efficient ionization and precise quantification of the compound (1).

The proposed method in this study performed well. The researchers reported that the limit of detection (LOD) for ethyl carbamate was measured at 4.4 µg L⁻¹, which was significantly lower than many conventional approaches (1). The method also demonstrated excellent reproducibility, with intra-day precision ranging from 3.2% to 3.7% and inter-day precision of 1.6% (1). These performance metrics suggest the approach can meet both regulatory and industrial needs for routine monitoring.

In practical trials, the team applied the FastGC-PICI-TOFMS technique to four distinct types of Chinese liquor, each with unique flavor profiles and production methods (1). The results confirmed the method’s versatility and accuracy across different product types, reinforcing its potential for broad application in the liquor industry. Beyond Chinese liquor, the researchers believe the technique could be adapted to test other alcoholic beverages, including wines and spirits, where ethyl carbamate contamination is also a concern (1).

One of the key advantages of the method is its high-throughput capability. By cutting analysis time to less than four minutes per sample and removing the need for pre-treatment, producers can screen a far greater number of batches during manufacturing (1). This improvement could be useful for quality control departments, helping them detect contamination earlier and respond more swiftly to potential safety issues (1).

The study also explored how column temperature and split ratio in FastGC influence separation efficiency, providing valuable optimization data for analytical chemists. Notably, the approach does not depend on high-resolution mass spectrometry (HRMS), which can be costly and less accessible to smaller laboratories (1).

What are the implications of this study?

There are several important implications to this study. As public health agencies and food safety regulators around the world push for stricter monitoring of carcinogenic compounds in consumables, having a rapid, reliable, and cost-effective method for EC detection could help ensure compliance while reducing the economic burden on producers (1).

Interest and consumption of alcoholic beverages is expected to continue to grow. As such, techniques like FastGC-PICI-TOFMS are expected to be utilized in food safety testing.

References

1. Li, Y.; Fan, Z.; Zhang, S.; et al. Rapid Measurement of Ethyl Carbamate in Chinese Liquor by Fast Gas Chromatography Photoionization-induced Chemical Ionization Mass Spectrometry. Talanta 2025, 282, 126965. DOI: 10.1016/j.talanta.2024.126965
2. U. S. Food and Drug Administration, Ethyl Carbamate. FDA.gov. Available at: https://www.fda.gov/food/process-contaminants-food/ethyl-carbamate (accessed 2025-08-13).