## 1 Introduction  
Tea (_Camellia sinensis_ L) and tea beverages are becoming more and more popular in the world because of their unique flavor and taste. It has been reported that drinking tea makes people cheerful, and also has many potential health benefits, which keeps tea consumption always at a high level [1; 2]. As a fully fermented tea, black tea has a richer flavor than other teas. According to its aroma characteristics, it can be divided into honey-sweet-flavored black tea, fruit-flavored black tea and floral-flavored black tea [3].  
Aroma is an important indicator of tea quality. Gas chromatography-mass spectrometry (GC-MS) can achieve the purpose of effectively separating and identifying volatile compounds [4]. There are many ways to extract the aroma of tea, such as headspace solid-phase microextraction (HS-SPME) [5], stir bar sorptive extraction (SBSE) [6], solvent-assisted flavor evaporation (SAFE) [7], and simultaneous distillation extraction (SDE) [8]. These aroma extraction methods have their advantages and disadvantages: HS-SPME can quickly extract volatile compounds, but is not particularly effective for some compounds [9]; SBSE coating has low selectivity, and it is difficult to meet the analysis requirements of complex systems; experimental results may be affected by high temperature during the SDE process [7]; and trace compounds could be extracted more accurately by SAFE [10]. So far, more than 600 volatile compounds have been detected in black tea (including black tea beverages) [11]. Therefore, SAFE combined with SPME was used for the analysis of the aroma compounds of black tea.  
There have been many studies on the aroma of black tea, but systematic comparisons of several famous black tea aromas in China are rarely reported. \"Qun Fang Zui\" Keemun (KM), the \"The Treasure of Tea\" Jinjunmei (JJM), and the \"Flower of Famous Tea\" Dianhong (DH) black teas can be regarded as representatives of Chinese black tea. In addition, the floral fragrance in the tea is particularly important. Some scented teas such as jasmine tea have become more and more popular in recent years. This makes it attractive to enhance the floral aroma of black tea. Previous studies have pointed out that the interactions between two aroma compounds include no effect, additive effect, synergistic effect, and masking effect [12]. In recent years, this has gradually attracted more and more attention, and studies have begun to pay attention to the sensory interactions among flavor compounds [13; 14]. The research has focused on the identification of aroma compounds, and it is very meaningful to study the interactions among aroma components and their contribution to the aroma of black tea.  
In this study, GC-MS combined with gas chromatography-olfactometry (GC-O) were used to identify volatile compounds, and the odor activity value (OAV) was calculated. The OAV is determined by the concentration and odor threshold value, which can show a relative aroma contribution [15]. In addition, an aroma extract dilution analysis (AEDA) was performed to determine flavor dilution (FD) to fully identify key aroma compounds. Furthermore, the perceptual interactions of 10 key floral compounds with the methyl salicate (MeSA) as the most important ester in black tea were analyzed. Then, the application of [PERSON]'s law in aroma interaction was explored.  
As far as we know, there is no research which has systematically compared the aromas of several famous Chinese black teas and deeply explored the perceptual interactions among aroma compounds. In this study, we aim to identify the key aroma compounds of JJM, KM, and DH, three representative Chinese black teas, through the combination of SAFE and HS-SPME, and analyze the similarities and differences of their aroma composition. On this basis, we explore the perceptual interactions among MeSA and floral compounds. The results of this study can improve the flavor of black tea beverages and provide more theoretical support for future black tea flavor innovation.