## 2 Results and Discussion
### Sample Analysis  
To check the applicability of the developed method, 14 jujube samples including black spot-infected and -uninfected jujubes from seven jujube yards in South Xinjiang were analyzed. From Table 3, we can see that TeA was found in lower levels in all the samples, and the amounts were associated with the infection levels: Uninfected jujube (<LOQ \(\sim\)1.0933 \(\upmu\)g g\({}^{-1}\)) <infected jujube (0.1373-8.2375 \(\upmu\)g g\({}^{-1}\)), and AOH (0-0.0228 \(\upmu\)g g\({}^{-1}\)), AME (0-0.0692 \(\upmu\)g g\({}^{-1}\)), and TEN (<LOQ \(\sim\)0.0247 \(\upmu\)g g\({}^{-1}\)). Except for uninfected jujubes, in the other infected samples the four _Alternaria_ toxins were all detected. The distinction of _Alternaria_ toxins detected in black spot-infected jujubes among the seven yards was caused by the type of _Alternaria_ species [38] and environmental factors [39].  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Analyte** & **TeA** & **AOH** & **AME** & **TEN** \\ \hline Linear range (ug mL\({}^{-1}\)) & 0.01–1 & 0.01–1 & 0.01–1 & 0.01–1 & 0.01–1 \\ Calibration curves in pure solvent & & & & \\ Equation of the curve & y = 9229.1x – 323.72 & y = 19,285x + 863.15 & y = 23,975x + 983 & y = 221,548x + 2969.8 \\ Correlation coefficient (R\({}^{2}\)) & 0.9996 & 0.9893 & 0.9855 & 0.9922 \\ Calibration curves in a blank jubing sample & & & & \\ Equation of the curve & y = 2489.1x – 54.376 & y = 12,613x – 471.32 & y = 15,189x – 371 & y = 73,096x + 495.47 \\ Correlation coefficient (R\({}^{2}\)) & 0.9897 & 0.9997 & 0.9866 & 0.9980 \\ Slope ratio & 0.2697 & 0.6540 & 0.6335 & 0.3299 \\ Limit of Detection (LOD) (ug kg\({}^{-1}\)) & 0.14 & 0.26 & 0.22 & 0.20 \\ Limit of Quantitation (LOQ) (ug kg\({}^{-1}\)) & 0.47 & 0.87 & 0.72 & 0.66 \\ Intra-day precision (BSDV\({}^{-1}\), \(n=3\)) 2 & 0.1 & 2.8 & 1.1 & 0.8 \\ Inter-day precision (BSDV\({}^{-1}\), \(n=3\)) 2 & 2.4 & 3.0 & 5.0 & 1.9 \\ Average recovery \(\pm\) RSDV\({}^{-1}\) (\(n=3\)) for red jubing & & & & \\ Concentration (ug kg\({}^{-1}\)) & & & & \\
160 & 91.0 \(\pm\) 1.4 & 91.3 \(\pm\) 0.9 & 109.6 \(\pm\) 0.4 & 89.3 \(\pm\) 3.6 \\
80 & 87.1 \(\pm\) 4.4 & 86.0 \(\pm\) 2.9 & 93.0 \(\pm\) 4.8 & 86.5 \(\pm\) 3.3 \\
40 & 83.5 \(\pm\) 6.5 & 84.8 \(\pm\) 4.2 & 88.6 \(\pm\) 2.4 & 85.2 \(\pm\) 2.7 \\ \hline \hline \end{tabular} 1
[FOOTNOTE:1]Footnote 1: footnotetext: Relative standard deviation; 2  
\end{table}
Table 2: Analytical and statistical parameters of the proposed method for the determination of _Alternaria_ toxins.  
\begin{table}
\begin{tabular}{c c c c c c} \hline No. & Sample & Location & TeA & AOH & AME & TEN \\ \hline S-1 & Uninfected jubbe & 1.0933 (0.62) 1  & \(<\)LOO 2  & \(<\)LOO & 0.0104 (3.05) \\ S-2 & Infected jubbe & 8.2735 (3.62) & 0.0225 (0.69) & 0.0692 (1.85) & 0.0074 (3.42) \\ S-3 & Uninfected jubbe & 0.1817 (0.33) & \(<\)LOO & \(<\)LOO & 0.0078 (3.21) \\ S-4 & Infected jubbe & 3.3141 (2.58) & \(<\)LOO & \(<\)LOO & 0.0064 (4.63) \\ S-5 & Uninfected jubbe & 0.2944 (3.39) & \(<\)LOO & \(<\)LOO & 0.0029 (3.78) \\ S-6 & Infected jubbe & 0.8390 (0.55) & \(<\)LOO & \(<\)LOO & 0.0095 (3.41) \\ S-7 & Uninfected jubbe & \(<\)LOO & nd & \(<\)LOO & \(<\)LOO \\ S-8 & Infected jubbe & 0.1879 (1.04) & nd & nd & \(<\)LOO \\ S-9 & Uninfected jubbe & 0.1506 (5.04) & 0.0012 (83.33) & 0.0046 (2.38) & 0.0277 (0.55) \\ S-10 & Infected jubbe & 0.8506 (1.62) & \(<\)LOO & \(<\)LOO & 0.0058 (1.72) \\ S-11 & Uninfected jubbe & 0.0964 (8.66) & \(<\)LOO & \(<\)LOO & 0.0086 (1.64) \\ S-12 & Infected jubbe & 0.1373 (0.11) & 0.0015 (5.67) & 0.0011 (0.99) & 0.0072 (1.55) \\ S-13 & Uninfected jubbe & 0.4179 (0.42) & \(<\)LOO & \(<\)LOO & 0.0053 (2.63) \\ S-14 & Infected jubbe & 5.3881 (5.49) & \(<\)LOO & \(<\)LOO & 0.0070 (1.43) \\ \hline \end{tabular}
\end{table}
Table 3: _Alternaria_ toxins content (ug g\({}^{-1}\)) in different jubbe samples.