Cto 10a column oven

Agilent 1100 HPLC system was used for analyses of the cresol contaminants in soil samples. The analysis was carried out by employing a modular Shimadzu LC-10 system comprised of a LC-10 AD pump, a CTO-10A column oven, a SPD-10A UV-DAD detector with wavelength of 274 nm, a FLD detector, a CBM-10A interface, and a LC-10 Workstation. A LC-18 column (250 mm × 4 mm ID × 5 mm) was employed at 26°C and separations were conducted in the isocratic mode, using acetonitrile:acetate buffer (30:70; v/v) at a flow rate of 0.3 mL min − 1, with an injection volume (“loop”) of 20 mL and an accuracy of ±2%. The concentration of acetate buffer was 266 mM (101 mM of acetic acid and 165 mM of Sodium acetate trihydrate) in the HPLC analyses.

The HPLC system consisted of a JASCO PU-2080 Plus HPLC Pump (JASCO Corporation, Hachioji, Tokyo, Japan), SPD-10A UV–Vis detector (SHIMADZU Corporation, Kyoto, Japan), and CTO-10A column oven (SHIMADZU Corporation, Kyoto, Japan). A Wakosil-PTC (4.0 × 200 mm) column (FUJIFILM Wako Pure Chemical Corporation, Osaka, Japan) was used at 40 °C. PTC-amino acid mobile phases A and B (FUJIFILM Wako Pure Chemical Corporation, Osaka, Japan) were run in a linear gradient mode so that the proportion of mobile phase B was 70% in 15 min, and the flow rate was 1 mL/min. The detection wavelength was set at 254 nm and the sample injection volume at 10 µL.

The extracts in the volumetric flasks were filtered through a cellulose acetate syringe filter with a pore size of 0.45 μm (dismic‐25cs, Advantec, CA, USA) into 1 ml glass vials. The samples were analyzed with a high‐performance liquid chromatography (HPLC) system, using a 300 mm × 7.8 mm Rezex ion exclusion column (Phenomenex Inc., Torrance, CA, USA) attached to a Cation‐H guard column (Bio‐Rad, Richmond, CA, USA) held at 25°C. Analysis was performed by injecting 20 μl of sample or standard onto the column using an aqueous solution of 25 mM sulfuric acid (HPLC grade Baker Chemicals, Phillipsburg, NJ, USA) as the mobile phase, pumped isocratically at 0.6 ml/min, with peaks detected at 210 nm. The HPLC equipment consisted of a Shimadzu LC‐10AD pump, CTO‐10A column oven, SPD‐10Avp UV–vis detector (Shimadzu, Kyoto, Japan) and a Waters 717 plus auto‐sampler (Waters, Milford, MA, USA). Data acquisition and processing were undertaken using a PeakSimple Chromatography Data System (model 203) and PeakSimple software version 4.37 (SRI Instruments, Torrance, CA, USA). The oxalic acid peak was identified by comparing the retention time to a standard solution, and by spiking an already‐filtered sample containing a known amount of oxalic acid standard. The insoluble oxalate content of each sample was calculated by difference between the total and the soluble oxalate contents.