1260 infinity 2 diode array detector

HPLC-DAD determination of DON was performed using an Agilent Technologies 1260 Infinity HPLC system (Santa Clara, CA, USA) coupled with an Agilent 1260 Infinity II Diode Array Detector (DAD). A Phenomenex^® Gemini C18 column (Torrance, CA, USA) was used (150 × 4.6 mm, 5 µm particle size, 110 Å pore size). Absorbance reading was performed at 220 nm. Three mobile phases were prepared: phase A (methanol:water 10:90, v:v), phase B (acetonitrile:water 20:80, v:v) and phase C (100% methanol). The gradient applied was as follows: 0 min 100% A; 10 min 60% A and 40% B; 13 min 60% A and 40% B; 15 min 100% C; 25 min 100% C; 29 min 100% A until 40 min (for re-equilibrating the column). The flow rate was set at 1 mL/min. The column temperature was 40 °C, and the injection volume was 50 µL. DON retention time was 10.0 min. Quantification was carried out by using DON calibration curves prepared in methanol:water 10:90, v:v.
LOD and LOQ, considered as three and ten times the signal of the blank, respectively, were 12.6 and 42.0 μg kg⁻¹. Recovery was calculated using artificially DON-contaminated maize, extracting and analysing the mycotoxins as previously stated. Recovery was studied per triplicate at three different DON concentrations: 2.286, 1.143 and 0.571 μg DON kg⁻¹ maize. The respective average recoveries and standard deviations were 81.7 $\pm$ 9.5, 87.4 $\pm$ 13.3 and 91.3 $\pm$ 14.5%.

The chromatographic analyses were performed using an Agilent 1260 Infinity II HPLC (Agilent, Santa Clara, CA, USA) equipped with a 1260 Infinity II Quaternary Pump (model G7111A), 1260 Infinity II auto-sampler (model G7129A), 1260 Infinity II Multicolumn Thermostat (model G7116A), and 1260 Infinity II Diode Array Detector (model G7115A). The results were collected and integrated using Agilent OpenLAB CDS LC ChemStation software. The selected column was a Poroshell 120 EC-C18 (150 × 4.6 mm i.d., particle size 4 μm; Agilent, Santa Clara, CA, USA), working at 20 °C. Samples were dissolved in acetonitrile (ACN) (1 mg/mL) and analyzed using as the mobile phase a mixture of water (channel A) and acetonitrile (channel B), both containing 0.1% v/v of trifluoroacetic acid (TFA). The gradient elution started from 90% of A to reach the 90% of B over 6 min at a flow rate of 0.8 mL/min, for a total run of 15 min. The UV detector was set at a length of 254 nm. HPLC chromatograms of 1d and 1h, reported in the supporting information (Figures S1 and S2), confirmed a high grade of purity (99%).

The liquid chromatography
system was an Agilent 1260 Infinity II HPLC (Agilent, Santa Clara,
CA) consisting of a 1260 Infinity II Quaternary Pump (model G7111A),
1260 Infinity II autosampler (model G7129A), a 1260 Infinity II Multicolumn
Thermostat (model G7116A), and a 1260 Infinity II Diode Array Detector
(model G7115A). Data were acquired and integrated using the software
Agilent OpenLab CDS LC ChemStation. The separation was performed using
a Poroshell 120 EC-C18 (150 × 4.6 mm i.d., particle size 4 μm;
Agilent, Santa Clara), maintained at 20 °C. The samples were
run using a mixture of water (A) and acetonitrile (B) enriched with
trifluoroacetic acid (0.1% v/v). The gradient used was from 80% A
to 100% B over 10 min. The flow rate was 0.8 mL/min. The UV detector
was set at a length of 254 nm. Enantioselective HPLC analyses were
performed using the same above-described conditions except for the
stationary phase, which was a Chiralcel OJ[-RH] column (150 ×
4.6 mm, 5 μm).