Strata x aw

HPLC-grade acetonitrile, methanol, and isopropanol were purchased from J.T. Baker (Deventer, The Netherlands). Ethylenediaminetetraacetic acid (EDTA), sodium chloride, and sodium hydroxide were from POCH (Gliwice, Poland), and potassium hydrogen phosphate (K₂HPO₄) was from Chempur (Piekary Śląskie, Poland). Ammonium acetate, heptafluorobutyric acid (HFBA), and trichloroacetic acid (TCA) were obtained from Sigma–Aldrich, (St. Louis, MO, USA). Formic acid was from Fluka (Charlotte, NC, USA). Syringe 0.22 µm hydrophilic polyvinylidene fluoride (PVDF) membrane filters were purchased from Restek (Bellefonte, PA, USA). Ultra-pure water was generated by a Millipore Milli-Q System (Millipore, Molsheim, France).
The analytical reference standards of DHSTR, GEN, KAN, NEO, PAR, STR, and SPC were purchased from Dr Ehrenstorfer (Augsburg, Germany), and AMI, APR, HYG, RIB, SIS, TOB from Sigma–Aldrich (St. Louis, MO, USA). Strata X (100 mg, 6 mL), Strata X-CW (100 mg, 6 mL), and Strata X-AW (100 mg, 6 mL) cartridges were from Phenomenex (Torrance, CA, USA). Oasis HLB (60 mg, 3 mL) cartridges were from Waters (Milford, MA, USA). All matrices were obtained from local supermarkets or were originating from the Polish official residue control program. Samples were analyzed to ensure the absence of aminoglycoside residues and kept frozen at −18 °C until use.

Three types of resins were used:

Nucleophilic Scavengers (non-regenerable): Siliabond from SiliCycle (Quebec, QC, Canada) and Ethylenediamino purchased from Sigma-Aldrich.

Anionic Mixed Mode (regenerable): Oasis MAX from Waters (Mildford, MA, USA), Bond Elut Certify II from Varian (Palo Alto, CA, USA), Strata X-A and Strata X-AW from Phenomenex (Torrance, CA, USA). This type of resins required a previous conditioning step with methanol and vacuum drying under nitrogen stream.

Anionic Pure Mode (regenerable): Dowex^TM 1 × 2 50–100 and Amberlite^® IRA 900 were purchased from Sigma–Aldrich.

Resin characteristics are shown in Table 3.