Ulc ms grade acetonitrile

The pure solution of RTX was Truxima^® (10 g/L, Celltrion Healthcare, Budapest, Hungary) for LC-MS/HRMS assay and Rixathon^® (10 g/L, Sandoz, Kundl, Austria) for LC-MS/MS assay. Full-length stable isotope-labeled rituximab (Arginine 13C6-15N4 and Lysine 13C6-15N2) (SIL-RTX) was purchased from Promise Advanced Proteomics (Grenoble, France). SIL-RTX presented with a purity > 95% and labeling > 99%. Stock solutions of RTX and SIL-RTX were prepared in water at 1 g/L and at 100 mg/L, respectively, and stored at +4 °C.
ULC/MS grade acetonitrile was obtained from Biosolve (Dieuze, France) and formic acid (FA) from Fisher Chemicals (Illkirch, France). Ultrapure water (resistivity 18.2 mΩ.cm) was obtained using a Milli-Q Plus^® system (Millipore, Molsheim, France). PBS buffer (pH 7.4, molarity 10X) was from Gibco (Thermo Fisher, Waltham, MA, USA). Trypsin Gold, Mass Spectrometry Grade were purchased from Promega (Madison, WI, USA). Propan-2-ol for analysis and trichloroacetic acid 20% for analysis were obtained from Carlo Erba Reagents (Val-de-Reuil, France). Ammonium bicarbonate for mass spectrometry was from Sigma-Aldrich (Saint-Quentin-Fallavier, France). Drug-free human plasma was provided by the regional blood service (EFS Rhône-Alpes and Ile-de-France, France). Low adsorption polypropylene microtubes from Dutsher (Brumath, France) were used throughout the study.

D-L-Phenylalanine (Sigma Aldrich, Buchs, Switzerland) was dissolved in 50/50 water/acetonitrile + 0.5% formic acid (water: MilliQ, in house; acetonitrile: Biosolve, Valkenswaard, the Netherlands; formic acid: Sigma Aldrich, Buchs, Switzerland) to give a 50 mM solution and further diluted to 1 mM in 50/50 water/acetonitrile. Oxaliplatin and titanocene dichloride (Sigma Aldrich, Buchs, Switzerland) were dissolved in ULC-MS grade acetonitrile (Biosolve, Valkenswaard, the Netherlands) and ultrasonicated for 30 min to give a 1 mM stock solution. Heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin (TMβ-cyclodextrin), heptakis(2,6-di-O-methyl)-β-cyclodextrin (DMβ-cylclodextrin) (Sigma Aldrich, Buchs, Switzerland), β-cyclodextrin (Fluka, Sigma Aldrich, Buchs, Switzerland), sucrose (Merck, Darmstadt, Germany), and maltose (Sigma Aldrich, Buchs, Switzerland) were dissolved in MilliQ water to a final concentration of 1 mM by shaking for 1 h at 21 °C and 12,000 rpm on a thermomixer (Eppendorf, Schönenbuch, Switzerland).
For measurement, samples at a concentration of 0.02 mM were prepared either in 50/50 water/acetonitrile, 50/50 water/acetonitrile + 0.5% formic acid, or methanol (Sigma Aldrich, Bruchs, Switzerland), either of the host and guest structures solely, or mixed in a 1:1 molar ratio.

ULC-MS grade acetonitrile, ethanol, 2-propanol, methanol and ultra-pure water were purchased from Biosolve (Chimie SARL, Dieuze, France; BV, Valkenswaard, Netherlands). Chloroform was purchased from Carlo Erba (Milan, Italy). NH₄COOH, NH₄F, and butylated hydroxytoluene (BHT) were purchased from Sigma Aldrich (Milan, Italy). The Q-TOF calibration solution was prepared in acetonitrile from Agilent Technologies Tuning mix (HP0321 solution, Agilent Technologies, Santa Clara, USA).
N-palmitoyl-d31-D-erythro-sphingosine (d31-Cer[NS]34:1, MW 569.1), N-[26-oleoyloxy(d9) hexacosanoyl]-d-erythro-sphingosine (Cer[EOS] (d18:1/26:0/18:1(d9), MW 967.6) and N-[26-oleoyloxy hexacosanoyl]-d-erythro-sphingosine (Cer[EOS] (d18:1/26:0/18:1), MW 958.6) were purchased from Avanti Polar Lipids (Alabaster, USA). Deuterated cholesterol sulfate sodium salt (d7-CHS, MW 495.3) and Hexadecanoic-9,9,10,10,11,11,12,12,13,13,14,14,15,15,16,16,16-d17 acid (d17-PA, MW 273.5) were purchased from CDN Isotopes Inc., (Pointe-Claire, Canada). Stock solution of the internal standard (iSTD) mixture of deuterated compounds was prepared in 2-propanol with the following concentrations: d7-CHS 40 µM, d17-PA acid 80 µM, d31-Cer16:0 10 µM. d9-CER[EOS] and CER[EOS] mixture (2 µM each in Chloroform/methanol (2:1)) was introduced to confirm identification of O-acylceramides.