Waters ostro 96 well plate 25mg

Approximately 20 mg of frozen tissue was collected in homogenization tubes (Bertin Technologies, Montigny-le-Bretonneux, France), with 2.8 mm ceramic (zirconium oxide) beads and 2 mL standard tube volume. Subsequently, the volume of 20 μL of an internal standard dilution solution was added to the sample and they were equilibrated on ice for 2 min. Subsequently, 300 μL of an 1% formic acid in acetonitrile was added and vortexed for 20 s. The tissue samples were homogenized while using a tissue homogenizer (Bertin Technologies, France) over three cycles of 30 s at 5500 rpm each with a 10-s pause interval between cycles. After homogenization, the samples were centrifuged at 14,000 rpm for 15 min. at 4 °C. Supernatant was loaded into a Waters Ostro 96 well plate 25mg (Part No. 186005518). The same homogenized steps were repeated with a second extraction solvent (acetonitrile:water, 90:10, 1% formic acid). Collected supernatants were passed through a Waters Ostro 96 well plate 25mg (Part No. 186005518) using a vacuum, subsequently 110 μL of filtrate was mixed with 400 μL 0.1% formic acid in water. A volume of 5 μL of was then injected into the LC-MS/MS system.

Paclitaxel, docetaxel, vinblastine, vinorelbine, pemetrexed, carboplatin, etoposide, cyclophosphamide, ifosfamide, gemcitabine, irinotecan, SN-38, and vindoline (internal standard, IS) were purchased from Sigma-Aldrich Corporation (St. Louis, MO, USA). All were corrected for purity and salt forms when weighed or diluted for standard stocks, whose chemical structures are shown in Figure 1. HPLC-grade methanol and acetonitrile were obtained from Merck Company (Darmstadt, Germany). HPLC-grade formic acid, dimethyl sulfoxide (DMSO), and ammonium acetate were purchased from the Tedia Company, Inc. (Fairfield, OH, USA). Ultra-purified water (0.22 μm) was self-made in the laboratory by a Milli-Q reagent water system (Merck KGaA, Darmstadt, Germany) and was used throughout. Waters Ostro 96-well plate (25 mg) was used for sample pretreatment (Waters, Milford, MA, USA). Human blank plasma was donated by Shanghai Red Cross Blood Center (Shanghai, China).