Agilent 7700 series

Leaf material of Stevia was extensively washed in distilled water then dried at 70 °C for 72 h. 4 mL of nitric acid (69%, w/v) and 2 mL of hydrogen peroxide (30%, w/v) were added to 100 mg of dried leaves which was followed by the microwave-assisted destruction of samples at 200 °C and 1600 W for 15 min (Mars Xpress 5, CEM Corp., Matthews, NC, USA). After digestion samples were diluted with ddH₂O to the final volume of 20 mL. Se concentrations were determined by inductively coupled plasma mass spectrometry (ICP-MS) (Agilent 7700 Series, Santa Clara, CA, USA) using ⁸⁹Y as internal standard. Se concentrations are given in µg/g dry weight (DW).

Two-week-old seedlings of hydroponically-grown rice were exposed to a nutrient solution with either 0, 0.5 or 1 μM CdCl₂ for 14 days. Then the samples were washed with distilled water three times and separated into shoots and roots. Field-grown rice plants were harvested after grain ripening and separated into straw (shoot) and brown rice (grain).
All samples were dried at 70 °C for 3 d, and then digested with an acid mixture of HNO₃:HClO₄ (6:1 [v/v]) as described previously (Tang et al. 2017 (link)). The metal concentrations in the digest solutions were determined by inductively coupled plasma mass spectrometry (ICP-MS) (Agilent 7700 series, USA). The root-to-shoot translocation rates of metals were calculated as the amount of metal accumulated in the shoots as a percentage of the total amount of metal accumulated in the whole plant, as described by Miyadate et al. (2011 (link)).

Prior to the measurement of the Ni content of the soil (initial and final value) 200 g of soil samples were dried (105 °C, 24 h) and digested in aqua regia (hydrochloric acid: nitric acid = 3:1) in a microwave oven (Anton Paar Multiwave 3000, Graz, Austria). Ni concentration was measured by inductively coupled plasma atomic/optical emission spectrometer (ICP-OES, Perkin Elmer Optima 7000DV, Waltham, MA, USA) [51 (link)], and given in ppm (equals µg/g dry weight (DW)). The Ni content of the plant organs (root and shoot) were measured with inductively-coupled plasma mass spectrometry (ICP-MS, Agilent 7700 Series, Santa Clara, CA, USA) as described by Lehotai et al. [52 (link)] and given in ppm (equals µg/g dry weight (DW)).
Bioaccumulation factor (BAF; ratio of Ni concentration in the plant to the soil) [53 (link)] and translocation factor for Ni (TF, Ni concentration in the shoot/root) [54 ] were calculated to assess the Ni uptake potential of the O. lesbiaca seedlings.

Liver, muscle, gill, brain, and kidney tissues were collected to determine arsenic concentration. Whereas, Mn concentration was determined in the feed and fish muscle. The tissues samples and diets were undergoing processing within a microwave digestion system (Microwave Reaction System, Multiwave PRO, Anton Paar GmbH, Austria, Europe). The Inductively Coupled Plasma Mass Spectrometry (ICP-MS) technique (Agilent 7700 series, Agilent Technologies, USA) was employed for the analysis, in accordance with the methodology outlined by Kumar et al^{28 (link),29 (link)}.

Briefly, homogenate samples were lyophilised and then digested with nitric acid (65% Suprapur, Merck, St. Louis, MO, USA) overnight, followed by heating at 90°C for 20 min using a heat block. Samples were then removed from the heat block and an equivalent volume of hydrogen peroxide (30% Aristar, BDH, Radnor, PA, USA) added to each sample. Once samples had finished digesting, they were heated for a further 15 min at 70°C. Samples were then diluted with 1% nitric acid diluent. Measurements were made using an Agilent 7700 series ICP‐MS instrument under routine multi‐element operating conditions using a helium reaction gas cell. The instrument was calibrated using 0, 5, 10, 50, 100, and 500 ppb of certified multi‐element ICP‐MS standard calibration solutions (ICP‐MS‐CAL2‐1, ICP‐MS‐CAL‐3, and ICP‐MS‐CAL‐4, Accustandard, New Haven, CT, USA) for a range of elements, and we also utilized a certified internal standard solution containing 200 ppb of Yttrium (Y89) as a control (ICP‐MS‐IS‐MIX1‐1, Accustandard).

For measurement of total zinc 5.0 × 10⁵ cells for each cell line (PNT1A, LNCaP, DU145 and PC3) were cultured in 60mm cell culture dishes in 5mls serum media overnight. Next day serum media was aspirated and cells were washed briefly for 10–20 seconds with 2mLs of Milli-Q water. A final volume of 500μL of Milli-Q water was added and cells were scraped and the lysate collected into a 1.5 mL eppendorf tube. Cell lysates were freeze-dried, nitric acid (50 µL of 65%, Suprapur, Merck) was added to each cell pellet, and the pellets were digested overnight at room temperature. The samples were heated using a heating block at 90°C for 20 min to a volume of ∼40 µL. To each sample 460µL of 1% (v/v) of nitric acid diluent was added to a final Volume of 0.5 mL. Measurements were made using an Agilent 7700 series ICP-MS instrument under routine multi-element operating conditions using a helium reaction gas cell. The instrument was calibrated using 0, 5, 10, 50, 100 and 500 ppb of certified multi- element ICP-MS standard calibration solutions (ICP-MS-CAL2-1, ICP-MS-CAL-3 and ICP-MS-CAL-4, Accustandard) for a range of elements. A certified internal standard solution containing 200 ppb of Yttrium (Y89) was used as an internal control (ICP- MS-IS-MIX1-1, Accustandard).

Cellular samples, which were washed with cold PBS 3 times followed by treatment with trypsin-EDTA (T4049, Sigma-Aldrich) for 5 min, were counted, and all samples were simultaneously lysed with the same amount of RIPA buffer. Media samples were collected, and the volume of the samples was measured. Subsequently, media samples were collected, and the volume of the samples was measured. The concentration of nPt in the samples was measured by inductively coupled plasma mass spectrometry (ICP-MS) with an Agilent 7700 Series instrument (Agilent Technologies, Tokyo, Japan). The instrument was operated with an RF power of 1.5 kW and a carrier gas flow rate of 1.05 L/min Ar. The following isotopes were measured: 195Pt and 205Tl. Prior to ICP-MS analysis, sample aliquots were spiked with internal standards (205Tl) at a concentration of 2 ng/mL. Element concentrations were measured by external 6-to-11-point-calibration with internal standard correction. For the control samples, cells cultured without nPt or media without nPt were used. To calculate the nPt concentrations, the obtained concentrations, which measured all platinum element, were divided by the cell number for cellular samples or by media volume for the samples. The concentrations are presented in μg/ml per 1 × 10⁷ cells for cellular samples or in μg/ml for media samples.