Security guard ultra 3 mm

LC/MS 8045 (Shimadzu, Kyoto, Japan) consist of a Prominence-I LC-2030C 3D Plus LC unit and an ESI-TQ-MS detector. The apparatus was equipped with a Kinetex 2.6 µm C18 100A (100 × 3.0 mm) column with a Security Guard ULTRA 3 mm (Phenomenex, Torrance, CA, USA). For separation, 0.1% aqueous formic acid (A) and methanol (B) were used as mobile phases with a flow rate of 0.35 mL·min⁻¹ at 35 °C, with these gradient conditions: 10% to 20% B in 0–5 min; from 20% to 60% B in 5–10 min; from 60% to 10% B in 10–13 min and 10% B up to 17 min.
Identification was performed based on the optimised MRM mode (Table 2) according to polyphenol standards as a mixture (MetaSci, Toronto, ON, Canada) while quantification was carried out based on the external standard method.

The analysis of phenolic acids and flavonoids content was carried out with the LC-MS 8045 apparatus (Shimadzu, Kyoto, Japan) equipped with ESI type ion source. The separation of analytes was performed with a Prominence-I LC-2030C 3D Plus (Shimadzu, Kyoto, Japan) unit equipped with a Kinetex 2.6 µm C18 100A 100 × 3.0 mm column with a Security Guard ULTRA 3 mm (Phenomenex, Torrance, CA, USA).
We used 0.1% aqueous formic acid (A) and methanol with 0.1% of formic acid (B) (Sigma-Aldrich, Steinheim, Germany) as mobile phases. The gradient programme was as follows: from 10% to 20% B in 0–5 min; from 20% to 60% B in 5–10 min; from 60% to 10% B in 10–13 min; 10% B up to 17 min. The mobile phase flow was 0.35 mL·min⁻¹ at 35 °C.
The screening of non-volatiles was carried out with polyphenols: standard mixture of phenolic acids and alcohols and polyphenols: standard flavonoids mixtures (MetaSci, Toronto, ON, Canada).
The identified compounds were quantified using the MRM mode (Table 1) referring to the calibration curve. The analyses were performed in three repetitions.