## 1 Introduction  
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in the deaths of over 6 million people on a global scale since the start of the COVID-19 pandemic in 2019 [1]. Due to the widespread expansion of this disease, along with its high capacity for infection even among asymptomatic individuals, there have been multiple studies on the development of technology and tools that would aid in its rapid screening and diagnosis [2, 3, 4, 5]. The most common tools currently used for confirmatory diagnosis are the reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) test, which has been known to have \(\sim\)90% sensitivity, on average [6, 7, 8], and the antigen test, which varies widely in terms of sensitivity and can range from 35 to 72% depending on the brand [6, 7, 9]. Despite the high sensitivity RT-qPCR is known for, there are several disadvantage factors that can lead to false negatives such as a degraded sample or inadequate sample collection, a limit of detection higher than the available viral content, viral mutations, and a poor performance in sample testing [10]. False negative tests can result in further spreading of the disease by undiagnosed patients. Additionally, PCR-based tests seem to have a long turnaround time, with individuals receiving a notification of their test results 24-48 h after specimen collection, further enhancing viral circulation. On the other hand, antigen tests are more efficient for patient screening, as they produce swift responses, are less expensive, and allow for self-testing [7; 9]. Unfortunately, the sensitivity of the assay is sacrificed in exchange for a rapid response time. The sensitivity is even further reduced in asymptomatic populations [9]. Moreover, both RT-qPCR and antigen diagnostic tests can require a marginally invasive and uncomfortable sample collection from the patient [11], which could discourage individuals from seeking diagnostic services. There remains a pressing need for effective screening and diagnostic testing for public health surveillance, as SARS-CoV-2 has been proven to cause severe health outcomes. Some other methods of detection that have been preliminarily conceptualized include--but are not limited to--the use of analytical instrumentation [4; 12], e-noses [13], and canines [4; 12; 14]. Each of the aforementioned research studies have implemented the analysis of volatile organic compounds (VOCs) that are characteristic of SARS-CoV-2-infected individuals. VOCs are emitted by humans and other living organisms through various bodily secretions such as breath, saliva, urine, and sweat [15; 16]. These VOCs can change over time and are often influenced by alterations in metabolic conditions, such as those induced by diseases [17]. Multiple reviews have been published over the past decade on the scent of diseases and how odor expression can potentially be used to diagnose various ailments such as gastro-intestinal diseases, infected wounds, and cancer [17; 18; 19]. Recently, the diagnosis of SARS-CoV-2 infection through the analysis of exhaled breath VOCs has become more thoroughly explored as an alternative screening method [3; 20; 21; 22]. In 2020, [PERSON] et al. performed a preliminary study wherein they discovered that they were able to distinguish between individuals who were SARS-CoV-2-infected and those who were presenting similar symptoms using gas chromatography (GC) and ion mobility spectroscopy with approximately 80.7% accuracy [22]. They hypothesized that a series of compounds including methanol and various ketones could provide a foundation for the development of a breath test for SARS-CoV-2 infection. Another study in 2021 commented on the reduced concentrations of acetone in the breath samples of SARS-CoV-2-infected individuals [20]. Additionally, [PERSON] et al. (2021) assessed the opportunities and challenges of using a breathalyzer for the diagnosis of SARS-CoV-2 infections.