7700 instrument

Mineral and trace element levels of T. ferdinandiana fruit, leaf and seedcoat were determined based on the methods described previously (17 (link)) and expressed on a dry weight basis. Briefly, samples (ca. 0.3 g) were subjected to overnight slow digestion at room temperature and followed by microwave digestion (MarsXpress, CEM, Matthews, NC, USA) at a gradual increase in temperature. The levels of minerals were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES, 700 Series, Agilent, VIC, Australia) and the trace elements were analyzed using ICP-MS for greater sensitivity on a 7700 instrument (Agilent, Tokyo, Japan). Operating conditions and parameters of ICP-OES were recorded as follows: operating power 1.20 KW, plasma gas flow rate 15.0 L/min, auxiliary gas flow rate 1.50 L/min, nebuliser gas flow rate 0.90 L/min, sample uptake 50 s, pump rate 25 rpm and rinse time 30 s. The elements were recorded at the following wavelengths (nm): Ca 370.602 (nm), K 766.491 (nm), Mg 383.829 (nm), Na 568.821 (nm) and P 185.878 (nm). Operating conditions of the ICP-MS were recorded as follows: radio frequency power 1,350 W, carrier gas 0.8 L/min (argon) and gas flow rate 4.5 mL/min (helium reaction cell). Standard reference materials were used for the quality control and were treated similarly to the samples (19 (link)).

Leaf and root samples between 50 and 100 mg were mineralised alongside spinach leaf SRM (NIST 1570a) at the Imperial College London MAGIC Laboratories in 100 mL PFA vessels with 8 mL of 15.4 M HNO₃ and 2 mL of 30–32% H₂O₂ using a Milestone Ethos EZ microwave system, fitted with a SK-10 high pressure rotor. The digestion encompassed heating of the samples to 90 °C for 15 min and to 180 °C for 30 min. The concentrations of Cd were then determined on a 10% sample aliquot using inductively coupled plasma quadrupole mass spectrometry (ICP-Q-MS) either at the Open University with an Agilent 8800 triple quadrupole instrument or at the Natural History Museum London with an Agilent 7700× instrument.
The yeast cells were mineralised alongside cabbage leaf SRM (IAEA-359) for 8 h in 5 mL of 70% nitric acid (TraceSELECT™ grade, Sigma-Aldrich) in closed glass vessels at 110 °C at the Chemical Analysis Facility, University of Reading. Following digestion, the total Cd concentrations of the samples were determined on a 10% sample aliquot by ICP-Q-MS using a Thermo Scientific iCAP instrument.