## 1 Introduction  
Aroma, flavor and appearance are important aspects of the evaluation of green tea [1] and other products such as spice tea [2]. Many researchers have studied green tea for its aromatic volatile compounds to understand the aroma characteristics of green teas [3; 4; 5; 6; 7; 8; 9; 10; 11; 12]. However, in most prior research a limited number of green tea samples were used and the sample preparation did not reflect how green tea commonly is prepared by consumers [13; 14; 15]. In one study [12], for example, 60 g of green tea were brewed in 1 L of 60 \({}^{\circ}\)C water for 5 min; the green tea liquor then was steam distilled and concentrated to 10 \(\upmu\)L for gas-chromotographic analysis. Typical brewing methods recommend using 2 g of green tea in 55 mL at 60-70 \({}^{\circ}\)C for 1-2 min [16].  
Various green teas are available to consumers that represent different processing methods, harvest times, plant varieties and growing regions, all of which may contribute to different aroma characteristics in each tea [13]. For example, [PERSON] [17] used a solid-phase micro-extraction (SPME) method and found that volatile compounds were lower in teas grown in lower temperatures than ones picked from the same fields a year later when temperatures were warmer. Studying aromatic volatile compounds from brewed green tea liquor can help researchers to understand the composition of tea brewed as consumers actually would consume it. Recently it was suggested that sensory quality of Japanese green tea could be classified as either high or low using gas chromatography-mass spectroscopy (GC-MS) techniques on actual brewed samples [18].  
Volatile compounds in green teas extracted with solvents have been studied extensively using gas chromatography-mass spectrometry (GC-MS) to understand the differences in green tea aromatic components [19]. More than 600 volatile compounds have been identified through extensive research on green tea [20]. Researchers have studied green tea aroma in _Hojicha_ (roasted green tea from Japan) [21], _Bach-Mao_ tea (Vietnamese green tea) [22], _Sencha_-type spring green teas (steamed green tea from Japan) [23], _Kabusecha_ (a Japanese green tea made from tea leaves grown in the shade) and _Sencha_ (steam-processed green tea from Japan) [5]. [PERSON] [7] identified 41 volatile compounds from four commercial Korean green teas; two samples were steam-processed and two were roast-processed. [PERSON] and [PERSON] [11] used GC-MS and found 54 compounds from _Kamairi-cha_ (a Japanese tea; roast-processed), _Longjing_ tea (a Chinese tea; roast-processed) and _Sencha_. Eighteen volatile compounds were found in 23 Chinese green teas and 1-penten-3-ol, linalool, terpineol, citral, citronellol, nerol, geraniol and others commonly were present [24]. In another study 97 compounds common to teas from two regions in China were found and the authors were able to discriminate among the teas of two regions using those compounds measured by GC-MS analysis [25]. A review of recent studies on volatile compounds in tea did not indicate any studies had been conducted using brewed green tea and headspace analysis [26].  
SPME is a type of a headspace sampling, which studies the volatile compounds in the space above a sample in a sealed container [27]. Thus, using SPME with green tea brewed as a consumer typically would brew it may help understand the volatiles that would be in the aroma of green as consumers drink it. SPME is a convenient technique because there is no complicated sample preparation and it is environmentally friendly because it does not require any solvents. The objectives of this study were to use GC-MS paired with SPME to (a) identify common volatile compounds in the brewed liquor of awide range of green tea samples from various countries and (b) determine if green teas from different regions can be discriminated based on volatile composition in samples prepared for normal consumption.