Series 200 hplc

Soluble carbohydrates were extracted and analyzed following the protocol of Tattini et al.^{25 (link)}. Briefly, 5 ml of 75% ethanol was added to 200 mg of powdered fresh leaves. Samples were sonicated for 20 min. and centrifuged for 30 min at 10,000 g/min at room temperature to pellet the insoluble material. The supernatant was removed and the pellet was extracted twice as above. The ethanol fraction was reduced to dryness under vacuum and finally rinsed with 10 ml of water (pH 7.0). The aqueous extract was purified through –CH and –SAX Bond-Elute cartridges (Varian, Harbor City, CA, USA), and the eluate was reduced to dryness under vacuum at 35 °C. Samples were rinsed with 2 ml of ultrapure water and injected in a Series 200 HPLC equipped with 200-RI detector (Perkin Elmer), and separated on an 8 × 300 mm SC1011 column (Showa Denko, Tokyo, Japan) maintained at 88 ± 1 °C. Eluent was ultrapure water at a flow rate of 0.8 ml min⁻¹. Sorbitol was added as internal standard.

The following instruments were used: PTR-35 multirotator (Grant-bio, Cambridge, GB), Minispin centrifuge (Eppendorf, Hamburg, Germany), Series 200 HPLC (Perkin Elmer, Waltham, MA, USA), Purospher RP18-e (125 × 3 mm, 5 μm, Merck) reversed phase column.

Urine samples were collected from workers after a shift at work. The samples were collected from May 2021 to June 2021 and were stored at −80 °C until As determination and untargeted analysis. In all urine samples, the concentrations of tAs and creatinine were determined. The concentrations of urinary tAs and As species were normalized to creatinine. In the WH group, speciation studies of two As forms—iAs and arsenobetaine (AsB)—were additionally performed. The concentration of urinary tAs was determined using an ELAN DRC-e ICP-MS with a Dynamic Reaction Cell (Perkin Elmer, SCIEX, Waltham, MA, USA), and the concentration of As species—iAs and AsB—were determined using the instrument Series 200 HPLC (Perkin Elmer, SCIEX, Waltham, MA, USA). Further description of As determination in the urine was provided in the study by Janasik et al. [23 (link)].

The following instruments and reagents were used in this experiment: NexION 300D ICP-MS (PerkinElmer, Waltham, MA, USA) equipped with a concentric nebulizer and collision reaction cell; Series 200 HPLC (Perkin Elmer, Waltham, MA, USA); de-iron water was acquired using a Millipore water purifier (Millipore Ltd., Bedford, MA, USA); Phenomenex Luna 5 μm C18 (250 × 4.6 mm) column; ETH031 Microwave Digestion Instrument (Milestone Co., Roseland, NJ, USA); KQ-500DE Numerical Control Ultrasonic Cleaner (Kunshan Instrument Co., Shanghai, China); high-speed centrifuge (Eppendorf Co., Hamburg, Germany); cobalt standard solution (1000 mg/L) (SPEX Co., Metuchen, NJ, USA); vitamin B12 (Cyanobalamin, Sigma-Aldrich Co., Burlington, MA, USA); infant milk powder standard substances GBW 10277 (NIM, Beijing, China); nitric acid and methanol (chromatographic purity, Merck, Darmstadt, Germany); ethylenediamine tetraacetic acid disodium (EDTA), potassium dihydrogen phosphate, disodium hydrogen phosphate dodecahydrate, potassium ferrocyanide, anhydrous sodium acetate, trichloroacetic acid, zinc acetate, and acetic acid (analytical purity, Chinese Medicine Co., Beijing, China).

The following instruments were used in this study: Series 200 HPLC (Perkin Elmer, Waltham, MA, USA), Purospher RP18-e (125 mm × 3 mm, 5 μm, Merck) reversed phase column, Orion Star A212 Conductivity Meter with Orion 013005 MD electrode, Orion model 290A pH meter with Orion 910600 Thermo electrode (Thermo Fisher Scientific, Waltham, MA, USA), Grant-bio PTR-35 multirotator (Grant Instruments, Cambridge, UK), Minispin centrifuge (Eppendorf, Hamburg, Germany), TurboVap LV Concentration Evaporator (Zymark, Hopkinton, MA, USA), and a magnetic stirrer.