The sucrose content was determined by HPLC using an amino-propyl

The sucrose content was determined by HPLC using an amino-propyl silica column, Carbohydrate 5 μm, 4.6 x 150

mm, (Agilent Technologies, Switzerland). Acetonitrile:water 75:25 (v/v) was used as the eluent, with a flow rate of 1.5 ml/min and an injection volume of 50 μl. A refractive index detector (Agilent) was used. The run time was 10 min. Samples for sucrose determination were prepared by mixing 2.5 ml of water based green coffee extracts with 7.5 ml of acetonitrile. Dolutegravir The samples were filtered prior to injection with 0.45 μm PET syringe filters (Machenerey-Nagel). Volatile profiles of whole green coffee beans were measured using headspace solid phase micro extraction gas chromatography-mass spectrometry (HS SPME GC-MS). Five replicates of whole green coffee beans were weighed in SPME vials (m = 4.00 ± 0.07 g) and the headspace was purged with nitrogen before closing the vials. buy Lumacaftor A poly-dimethylsiloxan/divinylbenzene (PDMS/DVB) SPME fibre with a 65 μm thick film (Supelco, Sigma–Aldrich Chemie GmbH, Switzerland) and a DB-WAX (30 m × 250 μm × 0.25 μm) column (Agilent Technologies, Switzerland) were used. The SPME parameters (Gerstel, Switzerland) were as follows: incubation 10 min, agitating at 250 rpm; extraction time 30 min at 50 °C, pre-run bakeout 250 °C for 6 min. The GC-MS parameters (7890A/5975C, Agilent Technologies, Switzerland)

were: 37 °C for 1 min; 4 °C/min to 100 °C; 10 °C/min to 170 °C; 3 °C/min to 185 °C and 10 °C/min to 220 °C; splitless mode; flow 1 ml/min; EI source 70 eV, 230 °C; detector 150 °C. Data analysis and identification of the compounds was performed using the MSD Chemstation software (Version G1701 EA E.02.00.493, Agilent Technologies, Switzerland) and the NIST08 spectrum database. Chemical identification was performed by comparing the MS spectra to the database, the most intensive fragment ion was used for quantification. Statistical data analysis was performed using the R program package (RStudio, Version 0.97.551, R-3.0.2). Principal component analysis (PCA; prcomp, based on singular value decomposition)

was performed Y-27632 2HCl on centre-scaled data. During method optimisation, columns with different reverse phase sorbents (pentafluorophenyl, C18 endcapped and C18 core-shell) were evaluated, using either methanol or acetonitrile eluents. A common problem was the separation of caffeine from 5- and 4-CQA. Methanol was, in general, a more selective eluent then acetonitrile. Only the final method using the Poroshell column was able to provide sufficient separation between the CGAs and caffeine. A typical green coffee reverse phase HPLC chromatogram is shown in Fig. 2a. The newly developed method can also easily be adapted to create a rapid method for analysis of caffeine and CGAs in roasted coffee. The very low amount of sample that was loaded on the column also prolonged pre-column life and no sample pre-treatment was required.

Leave a Reply

Your email address will not be published. Required fields are marked *


You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>