Icp ms 7700

The morphology and size of the particles were characterized with TEM (JEOL JEM-1011)58 . The stability and surface charge of HPMA-coated NDs with Gd³⁺ complexes were tested by dispersing them in buffer solutions (50 mM citric acid buffer pH 2.0, 50 mM acetate buffer pH 4.5, 50 mM HEPES buffer pH 7.4, 50 mM TRIS buffer pH 8.5 and 1.5 M PBS buffer pH 7.4) for further experiments. Dynamic light scattering and zeta potential were recorded with a Zetasizer Nano ZS system (Malvern Instruments) at 37 °C at a concentration of 0.1 mg ml⁻¹.
To quantitatively measure the amount of Gd³⁺ complexes released from the nanosensors, the particles were mixed with buffer and incubated for a certain time. Then, cleavage conditions were stopped, the particles were centrifuged and the released Gd³⁺ complexes in supernatant were measured with an ICP MS 7700 (Agilent Technologies) instrument in duplicates. The non-cleavable ND-HPMA-Gd³⁺ conjugate was used as a control and processed under the same conditions. The relative release at a given time was calculated as a ratio of the amount released to the maximum release amount. A detailed description of these release experiments can be found in the Supplementary Information. The total amount of Gd³⁺ conjugated to HPMA-coated NDs was measured as ∼3.2% (weight percentage to NDs) using ICP AES (Spectro Arcos SOP).

Prior to analysis, samples were weighed (1 ml of EDTA blood) and digested in Teflon cuvettes by adding 7 ml of 65% nitric acid and 1 ml of 30% H₂O₂ in a microwave oven (Milestone START D, SK-10 T, Milestone Srl, Sorisole, Italy). Sample preparation was performed in three steps: heating for 15 min at 180°C, digestion for 15 min at 180°C, and cooling for 15 min. Also, blank samples containing a mixture of 65% nitric acid (7 ml) and 30% hydrogen peroxide (1 ml) were prepared and analyzed together with the samples. After cooling, samples and blanks were quantitatively transferred to normal 10 ml vessels. Graphite furnace atomic absorption spectrophotometry (AAS GTA 120 graphite tube atomizer, 200 series AA, Agilent technologies, Santa Clara, CA, USA) was used to determine the Cd concentration. The ICP-MS method (ICP-MS 7700, Agilent Technologies, Santa Clara, CA, USA) was used for the analysis of Hg, Cr, As, and Ni. An external standard technique (multielement standard solution 1 g/L in diluted nitric acid (Merck, Darmstadt, Germany)) was applied for calibration. The accuracy of both AAS and ICP-MS was validated with standard reference material (SRM) whole blood Level 2 (Seronorm TM, Sero, Billingstad, Norway). For SRM preparation and analysis, the same procedure was applied as for the EDTA-blood samples.

In order to remove the maximum contaminants, all plants were coppiced at the end of the growth season. To evaluate the yield, the above-ground biomass (shoots and leaves) of all plants was weighed in the field, using an electronic scale (Xiangshan Inc. model ACS- JC21D). Portions of the plants were oven-dried at 80 °C (to a constant mass) before being reweighed, to determine the average dry biomass. The below-ground biomass of all plants was the average root system estimated by the above-ground parts.
Dry plant tissues from each sample were ground with a stainless-steel grinder until all particles passed through a 0.149 mm nylon sieve, to determine the Cu concentration. Approximately 0.5 g of these samples were digested with a mixture of concentrated HNO₃ (10 mL), 30% H₂O₂ (1 mL), and concentrated HCl (2 mL) in Teflon tubes. These digested solutions had a constant volume of 25 mL with deionized water, and 10 mL of the suspensions were filtered through a nylon membrane (Magna-0.45 mm). The Cu concentration of these digested solutions were analyzed, using ICP-MS (Agilent ICPMS 7700) [40 (link)]. The translocation factor refers to the efficiency of the plant in translocating the accumulated metal from its roots to the shoots [41 (link)].