## 3 Results and Discussion
### Validation of the Multi-Mycotoxin Determination Method in Vegetable Drinks
#### 3.1.4 Matrix Effect  
Regarding the ionization of analytes, the matrix effect (ME) was studied, since this can interfere either by reducing or increasing the instrumental response to the analytes compared to that of the standards in solvents. It was observed that even though the intensities were of the same order, there was a certain effect of suppression or enhancement of the signal. To evaluate this ME, the calibration lines prepared from 500 from 2.5 ng/mL were used (after a linear least squares regression), and the slopes of the lines were compared (y = b + a:x; where \"x\" is the analyte concentration, \"y\" is the measured signal, \"b\" is the ordinate at the origin and \"a\" is the slope of the line). Thus, the relationship between the slope of the calibration curve of the solvent standard (aSTD) and that of the standard dissolved in matrix (aM) was calculated. \[\text{ME (\%)}=\frac{\text{aM}}{\text{aSTD}}\times 100\]  
To obtain ME (%), the value obtained was subtracted from 100, from which it is extracted that the ME (%) values equal to 0 do not present a matrix effect; if they are positive values, there is an exaltation of the signal, and if they are negative, it is due to signal suppression. In Figure 3, we can observe the result obtained both by matrices and the total mean of them, observing that there is mainly an inhibition of the signal for all \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Mycotoxin**} & \multirow{2}{*}{
\begin{tabular}{c} **Maximum Limits** * \\ **(ng/g)** \\ \end{tabular} } & \multicolumn{2}{c}{**OAT**} & \multicolumn{2}{c}{**ALMOND**} & \multicolumn{2}{c}{**RICE**} & \multicolumn{2}{c}{**SOY**} \\ \cline{3-10}  & & & **LQ** & **LD** & **LQ** & **LD** & **LQ** & **LD** & **LQ** & **LD** \\  & & **(ng/mL)** & **(ng/mL)** & **(ng/mL)** & **(ng/mL)** & **(ng/mL)** & **(ng/mL)** & **(ng/mL)** & **(ng/mL)** & **(ng/mL)** \\ \hline
**HT-2** & & 5.3 & 1.1 & 7.3 & 1.5 & 18.0 & 3.6 & 6.5 & 1.3 \\
**T-2** & & 4.2 & 0.8 & 5.8 & 1.2 & 14.2 & 2.8 & 5.1 & 1.0 \\
**ZEA** & 20 b & 0.7 & 0.1 & 0.9 & 0.2 & 2.3 & 0.5 & 0.8 & 0.2 \\ \hline
**AFB1** & 8 c; 2 b & 0.3 & 0.1 & 0.5 & 0.1 & 1.1 & 0.2 & 0.4 & 0.1 \\
**AFB2** & & & 0.3 & 0.1 & 0.5 & 0.1 & 1.1 & 0.2 & 0.4 & 0.1 \\
**AFG1** & Sum AFs: 10 c; 4 b & 0.3 & 0.1 & 0.5 & 0.1 & 1.1 & 0.2 & 0.4 & 0.1 \\
**AFG2** & & & 0.3 & 0.1 & 0.5 & 0.1 & 1.1 & 0.2 & 0.4 & 0.1 \\ \hline
**OTA** & 3 d,e & 2.0 & 0.4 & 2.8 & 0.6 & 2.6 & 1.1 & 1.6 & 0.3 \\ \hline
**BEA** & - & 1.0 & 0.2 & 1.4 & 0.3 & 3.4 & 0.7 & 1.2 & 0.2 \\ \hline
**ENA** & - & 1.0 & 0.2 & 1.4 & 0.3 & 3.4 & 0.7 & 1.2 & 0.2 \\
**ENA1** & - & 1.0 & 0.2 & 1.4 & 0.3 & 3.4 & 0.7 & 1.2 & 0.2 \\
**ENB** & - & 1.0 & 0.2 & 1.4 & 0.3 & 3.4 & 0.7 & 1.2 & 0.2 \\
**ENB1** & - & 1.0 & 0.2 & 1.4 & 0.3 & 3.4 & 0.7 & 1.2 & 0.2 \\ \hline
**AOH** & - & 2.3 & 0.5 & 2.8 & 0.6 & 7.9 & 1.6 & 2.9 & 0.6 \\
**AME** & - & 2.3 & 0.5 & 4.6 & 0.9 & 6.8 & 1.4 & 2.5 & 0.5 \\
**TENT** & - & 1.0 & 0.2 & 1.4 & 0.3 & 3.4 & 0.7 & 1.2 & 0.2 \\ \hline \hline \end{tabular}  
* Indicative levels for the sum of HT-2 and T-2 [22]. a Indicative or recommended levels in cereal-based products for human consumption obtained from the milling of cereals [22]. b Cereal products for human consumption [23]. c Almonds, pistachios and apricot kernels intended for direct human consumption or used as ingredients in food products. d All cereals and all cereal-based products, including processed cereal products [22]. e All products derived from unprocessed cereals, including processed cereal-based products and cereals intended for direct human consumption [23].  
\end{table} 
Table 3: Limits of quantification (LQ) and of detection (LD) in the four matrices studied, as well as the maximum limits and recommended values established in the EU. mycotoxins and that the soy matrix presents higher values of matrix effect, followed by rice, oats and, finally, almond. It should be noted that this last product only contains 2.5% raw material, so it is expected that the effect will be less than that of the other matrices.