Zorbax eclipse xdb c18 analytical column

HPLC analyses were performed on an Agilent 1260 Infinity system that includes a 1260 quaternary pump VL, a 1260 ALS autosampler, a 1260 Thermostatted Column Compartment, and a DAD Multiple Wavelength Detector (Agilent Technologies, Santa Clara, CA, USA). Detection wavelengths were set at 220, 230, 254, and 280 nm but only 220 nm was used for analysis. A Zorbax Eclipse XDB-C18 analytical column (5 μm, 4.6 × 150 mm) from Agilent Technologies was used. Mobile phase A consisted of 10 mM aqueous ammonium formate buffer titrated to pH 4.5. Mobile phase B consisted of acetonitrile. The injection volume of samples was 10 μL, flow rate was 1.0 mL/min, and the column temperature was set at 25°C. Samples were prepared by preparing a 1 mg/mL solution in 1:1 A:B. All samples were injected in duplicate with a wash in between each run. Run time was 10 minutes with a mobile phase ratio (isocratic) of 1:1 for A:B. Chromatograms were analyzed using the Agilent ChemStation Software (Agilent Technologies). Purity values were calculated from area under the curves of the absorbance at 220 nm of any resulting peaks.

The protocols in this section were approved by the Ethics Committee of Zhongshan Hospital, Xiamen University. The methods employed were performed in accordance with the approved guidelines. After acquiring informed consent, human saliva was collected from individual volunteers (two males and two females; Minimum age: 22; maximum age: 28) in the morning prior to oral cleaning. The collected saliva samples were centrifuged at 12,000 rpm for 20 min. The supernatant was collected and filtered through the 0.45 mm membrane filter to remove any debris. HBAMP was added into the human saliva to achieve the final concentration of 500 μg/ml. The saliva with HBAMP was incubated at 37 °C. At 0, 5, 20 and 60 min, 1 ml samples were taken from the total sample and served in the specific sample bottles, the machine will automatically extract samples from the bottles to detect. The samples were analysed by reversed-phase HPLC using Zorbax Eclipse XDB-C18 analytical column (150 × 4.6 mm, Agilent Technologies, Inc., Santa Clara, CA, USA) protected by a XDB-C18 guard column (4 × 4 mm). For the elution of HBAMP, a flow rate of 1.2 mL/min and a linear gradient from 88:12 to 65:35 (0.1% TFA in water: 0.1% TFA in acetonitrile) for 10 min were employed. Total run time of HPLC-UV (215 nm) analysis was 15 min and the injection volume was set at 40 μL.

Potassium tert-butoxide, 4-methoxybenzenethiol (3), benzenethiol (4), naphthalene-2-thiol (11) and potassium diphenylphosphide solution (0.5 M in THF) are commercially available and used as received. Methyl-4-iodocubane-1-carboxylate (1) and 1,4-diiodocubane (2) were synthesized according to ref. 18 (link). DMSO is Carlo Erba and stored under molecular sieves (4 Å). ¹H NMR and ¹³C NMR spectra were recorded on a 400 MHz Bruker nuclear magnetic resonance spectrometer. HR-MS were recorded on a Bruker, MicroTOF Q II equipment, operated with an ESI source in (positive/negative) mode, using nitrogen as nebulizing and drying gas and sodium formate 10 mM as internal standard. Gas chromatographic analyses were performed on a Varian 3900 GC with flame ionization detector on a FactorFour capillary column (VF-5 MS, 30 m, 0.32 mm, 0.25 micron). GC-MS analyses were carried out on a Shimadzu GC-MS QP5050 spectrometer, employing a 30 m, 0.32 mm, 0.25 micron, DB-5 MS column. Irradiation was performed in a reactor equipped with two 400 W lamps (Philips model Master HPI-T Plus, air- and water-cooled). The Fig. SI-1 in ESI† shows the spectrum of the lamps. HPLC analyses were carried out on a Waters 1525 Binary HPLC Pump connected to a Waters 2998 Photodiode Array Detector, and employing an Agilent Zorbax Eclipse XDB-C18 Analytical column (4.6 × 150 mm, 5 μm).