Fluorescence detector

To measure total D‐serine concentrations, brain homogenates were prepared from mice anesthetized with a lethal dose of sodium pentobarbital. Homogenates were centrifuged at 10,000 g for 12 min to collect supernatant. HPLC measurements were performed using a Waters Alliance instrument (Waters Corporation, Guyancourt, France) with a Shiseido Capcell PAK C18 MG100 column (4.6 × 250 mm; 5 μm). The column and sample compartments were kept at 27 and 8°C, respectively, and flow rate was set at 0.9 ml/min and run time was 41 min for all analyses. Amino acid standards and brain samples were derivatized in 325‐μl aliquots of a solution composed of treated with 1 mg/ml N‐acetylcysteine and 2 mg/ml o‐phthaldialdehyde in a 0.1 M borate buffer, pH 10.5. Amino acids were eluted in a gradient composed of phase A (sodium acetate 50 mM, pH 6.5) and phase B (methanol 100%) and evolving as follows: 0–7 min phase A 95% and phase B 5%, 7–19 min phase A 80% and phase B 20%, 19–27 min phase A 10% and phase B 90%, and 28–41 min phase A 95% and phase B 5%. Amino acid derivatives were detected using a Waters fluorescence detector (excitation 340 nm–emission 450 nm) and data were acquired using the Empower Pro software package (Waters Corporation, Guyancourt, France). Calibration of D‐serine detection was performed using a 4‐point standard curve.

Enrofloxacin separated by MNP-mAb conjugates was detected via HPLC using an XTerra RP18 column (Waters, Ireland). The chromatographic column was then equilibrated with a mixture of water-acetonitrile-methanol (800 : 170 : 30; v/v/v). The flow rate of the mobile phase was 1.2 mL/min. Dissociated samples (20 µL) were injected into the HPLC system (Waters) and the eluate was monitored for ENR using a fluorescence detector (Waters) at an excitation of 278 nm and an emission of 455 nm.