Agilent 5973n quadrupole mass selective detector

For AA detection in biscuits the HS-SPME fiber with a CAR/PDMS coating was manually introduced into the GC injection port at 250 °C (equipped with a glass liner, 0.75 mm I.D.) and kept for 3 min for desorption. The desorbed volatile compounds were separated in an Agilent Technologies 6890N Network gas chromatographer equipped with a DB-FFAP column (60 m × 0.25 mm I.D. × 0.25 μm film thickness) supplied by Agilent J&W Scientific (Folsom, CA, USA) connected to an Agilent 5973N quadrupole mass selective detector. Helium (Air Liquid, Portugal) was used as the carrier gas at a flow rate of 1.7 mL/min. The injection was performed in splitless mode. The GC oven program temperature was the same as described in Section 2.6. For the MS system, the temperatures of the transfer line, quadrupole and ionization source were 250 °C, 150 °C, and 250 °C, respectively. Electron impact mass spectra were recorded at 70 eV and the ionization current was about 30 μA. A delay time of 7 min was used. Under these chromatographic conditions, the run was 18 min. The acquisition was performed in an ion extraction chromatography (IEC) mode (71 and 55 m/z, for AA monitoring, with higher proportion for 71).

Methyl ester of fatty acids analysis were performed with gas chromatograph Agilent-6890 equipped with an Agilent-5973N quadrupole mass selective detector. A CPS ANALITICA CC-wax-MS (30 m × 0.25 mm ID, 0.25 μm film thickness) capillary column was used to separate FAMEs. The instrumental parameters were optimized using a 37-Component FAME mix (≥99%, Supelco, Bellefonte, PA, USA). Experimental condition of the GC/MS analyses were as in Canonico et al.^{77 (link)}. Main ions fragment were recorded and identification of fatty acids was achieved using the NIST reference mass spectra database (NIST, Mass Spectral Database 02, National Institute of Standards and Technology, Gaithersburg, MD 2002) MS search 2.0a (NIST, 2002, NIST, Ringoes, USA). The analyses were performed in triplicate.
The estimated limits of detection (LOD) and limits of quantification (LOQ), calculated as in Truzzi et al.^{76 (link),78 (link),79 (link)}, ranged for each FAME from ~4 μg mL⁻¹ to ~22 μg mL⁻¹, and from ~13 μg mL⁻¹ to ~66 μg mL⁻¹.