Ms single quadrupole hp 1100 msd detector

Standard chemicals, including protected amino acids, were purchased from commercial sources and used without further purification. Peptide purity was assessed by analytical RP HPLC performed on an 1100 series apparatus Agilent Technologies, Milan, Italy, using an XSelect Peptide CSH C18 column (Waters, Milford, MA, USA), 4.6 mm × 100 mm, 130 Å, 3.5 μm. MS (ESI) analysis was performed using an MS single quadrupole HP 1100 MSD detector (Agilent Technologies, Milan, Italy). The synthetic procedures by MW irradiation were performed with a Microwave Labstation for Synthesis (Micro-SYNTH, Bergamo, BG, IT) equipped with a built-in ATC-FO advanced fiber-optic automatic temperature control. Peptides isolation was performed by preparative RP HPLC performed on an 1100 series apparatus (Agilent), using an XSelect Peptide CSH C18 OBD column (Waters) 19 mm × 150 mm, 130 Å, 5 µm. The molecular weights of the purified peptides were verified by electrospray ionization (ESI)–mass spectrometry (MS) using an MS single quadrupole HP 1100 MSD detector (Agilent). Fluorescence measurements were performed with an LS-55 Fluorescence Spectrometer (Perkin Elmer, Milan, Italy). DLS measurements were performed with a Zetasizer Nano ZS (Malvern Panalytical, Malvern, UK). For full details, please see the Supporting Information.

Standard chemicals were obtained from commercial sources. Purification of the compounds was performed by flash chromatography over silica gel; eluent: cyclohexane/EtOAc 85:15. The purity of the final products was analyzed by reverse-phase (RP) HPLC, performed on Agilent 1100 series apparatus (Agilent, Technologies, Waldbronn, Germany), equipped with a RP column Phenomenex (Torrance, CA, USA) No 00D-4439-Y0 Gemini 3 μm C18 110 Å, LC column 100 mm × 3.0 mm; diode-array detector (DAD) λ = 210 nm and 254 nm; mobile phase: from 9:1 H₂O/acetonitrile (ACN) containing 0.1% formic acid to 2:8 H₂O/ACN containing 0.08% formic acid in 20 min, flow rate 1.0 mL min⁻¹. ESI-MS was done on a MS single quadrupole HP 1100 MSD detector (Agilent). ¹H NMR analysis was performed on a Varian Gemini 400 MHz apparatus (Agilent Technologies); peptide samples were dissolved in CDCl₃ or in DMSO-d6 to the final concentration of 0.01 M and analyzed in 5 mm tubes at rt. Water suppression required the PRESAT presaturation procedure. Chemical shifts (δ) are expressed as p.p.m., using the residual peak of the deuterated solvent as an internal standard (δH DMSO-d6 = 2.50 p.p.m., δH CDCl₃ = 7.27 p.p.m.).
Opioid radioligands, [³H]DAMGO, [³H]deltorphin-2 and [³H]U-69593, and human recombinant opioid receptors came from PerkinElmer (Krakow, Poland). GF/B glass fiber strips were purchased from Whatman (Brentford, UK).