Icap rq

Ultraviolet-visible (UV-Vis) absorption spectra were collected using a UV2450 spectrophotometer (Shimadzu, Kyoto, Japan). Dynamic light scattering (DLS) and zeta potential were measured using the Zetasizer Lab Blue instrument (Malvern Panalytical, Malvern, Worcs, UK). Transmission electron microscopy (TEM) imaging was performed in a Hitachi HT7800 TEM system at 100 kV. Elemental content was determined by iCAP RQ inductively coupled plasma mass spectrometry (ICP-MS) (Thermo, Waltham, MA, USA). For ICP-MS measurements in single-particle mode (spICP-MS), experiments were conducted on a NexION 350X ICP-MS instrument (PerkinElmer, Waltham, MA, USA), which was equipped with Syngistix Nano application software.

A batch of PEI/EDTA-Zn²⁺ solutions was prepared by mixing 0.4 g of EDTA, 0.8 g of PEI solution (50 wt% in water) and 0.4 g of Zn (NO₃)₂·6H₂O and diluted to 200 mL with distilled water. The pH values of these solutions were, respectively, tailored as 2, 4, 6, 8, 10 and 11 by adding a suitable amount of HNO₃ and NH₃·H₂O. After stirring for 24 h, these solutions concentrated to 50 mL in volume by ultrafiltration process. Subsequently, the concentrated solutions were diluted to 10,000 times its original weight with 1 wt% HNO₃, while the Zn²⁺ ions concentration in the diluted solution was lower than 176 ppb (by weight). The diluted solutions were then centrifuged at 6000 rpm for 10 min and the solutions sampled in the upper layer were analyzed for the Zn²⁺ ions concentration with inductively coupled plasma mass spectrometry (ICP-MS, iCAP RQ, Thermo Fisher Scientific Ltd., Germany). For adsorption analysis of Zn²⁺ ions with PEI polymer, the PEI-Zn²⁺ solutions were firstly prepared by mixing 0.8 g of PEI solution and 0.4 g of Zn (NO₃)₂·6H₂O. Likewise, the subsequent processes of sample preparation and characterization were described as the above.

For each sample, a total of 0.05 g of dry tissues power were weighed and immersed in 4 mL concentrated nitric acid with 2 mL 30% H₂O₂ overnight, and then were decocted with temperature gradient (60 °C for 1 h, 120 °C for 1 h, 160 °C for 1 h, 190 °C until the solution was clarified) using a graphite digestion instrument (DigiBlock ED54, Beijing, China). The content of extracted Na⁺ was measured by inductively coupled plasma-mass spectrometry (ICP-MS) (iCAP RQ, Thermo Fisher Scientific, 168 Third Avenue, Waltham, MA, USA) after acid catching, constant volume and filtration with three biological replicates per sample.

The mineral elements of AFH was estimated using inductively coupled plasma mass spectrometry (ICP-MS) based on the methods defined in Chinese National Food Safety Standards (GB 5009. 268–2016) [62 ]. Briefly, 0.5000 g of honey was dissolved in nitric acid (65%, 5 mL), and were allowed to digest under room temperature overnight. Then, the mixtures were dissolved in hydrogen peroxide (30%, 2 mL) before being digested at 140 °C for 2 h. The digestion was made up to 10 mL with nitric acid (2%) after being cooled. The solutions were centrifugated at 10,000 r/min for 10 min and the supernatant was kept to analysis.
Metal determination was determined using an inductively coupled plasma mass spectrometer (ICAPRQ, Thermo Fisher Scientific, MA, USA). The instrument was carried out with following conditions: RF power, 1500 W, plasma gas flow rate, 15 L/min, carrier gas flow rate, 0.8 L/min, auxiliary gas flow, 0.4 L/min, helium flow, 5.0 L/min, spray chamber temperature, 2 °C, and acquisition mode, spectrum. The content of each metal in honey was calculated with a corresponding standard curve, and expressed as mg/kg honey.

The intracranial tumor‐bearing rats were injected with 1 mL of PPA@DiR/MnO or iRPPA@DiR/MnO via the tail vein at a dose of 1 mg DiR kg⁻¹ body weight. The fluorescent images were obtained using an in vivo imaging system (Carestream IS 4000, USA) before injection and at 2, 4, 6, 12, 24, 48, and 72 h after injection. At 72 h post‐injection, rats were sacrificed to obtain the major organs (heart, lungs, liver, spleen, and kidneys) and tumors for ex vivo imaging. To detect the dynamic changes in MRI signal intensity, an in vivo MRI study was performed on a clinical 3.0 T MR system (Achieva; Philips Medical Systems). After injection of PPA@TMZ/MnO or iRPPA@TMZ/MnO via the tail vein at a dose of 2 mg Mn kg⁻¹ body weight, the tumor‐bearing rats were imaged at various time intervals by using the MRI unit with the same parameters as used in a previous study.^[33] The distribution and accumulation of Mn deposits in major organs and tumors were further detected by ICP‐MS. Briefly, before and 6, 12, and 24 h after injection of PPA@TMZ/MnO or iRPPA@TMZ/MnO, the major organs (heart, lungs, liver, spleen, and kidneys) and tumors were harvested, dissolved in a mixture of 30% hydrogen peroxide solution and nitric acid, and digested using a microwave system. The Mn content was then measured by ICP‐MS (iCAP RQ, Thermo Fisher Scientific, USA).

ICP-MS by an iCAP RQ (Thermo Scientific) was used to determine
the elemental composition of the samples. Prior to ICP analysis, the
samples were dissolved in a mixture of 6 mL of HCl, 2 mL of H₂SO₄, and 2 mL of HNO₃ and subsequently
digested in a microwave (Multiwave GO, Anton Paar) at 180 °C
for 30 min. For the ICP measurement, the samples were further diluted
with ultrapure water (18.2 MΩ·cm).