5110 icp oes

In vivo, tibia P retention rate was used to evaluate the bone P utilization of broilers (30 (link)); therefore, tibial osteoblastic P retention rate was determined in vitro to evaluate the osteoblastic P utilization. To determine the tibial osteoblastic P retention rate, the old medium was collected and pooled at every medium replacement. The total P contents in the fresh or old medium were determined by inductively coupled plasma optical emission spectrometry [5110 ICP-OES, Agilent Technologies Australia (M) Pty Ltd, Australia]. Accurately 1.0 ml of the fresh or old medium was taken in triplicate and digested with 12.5 ml of HNO₃ and 2.5 ml of HClO₄ at 200°C in a 50-ml calibrated flask until the solution became clear, and it was evaporated to almost dryness and diluted to about 15 ml with 2% HNO₃ before analyses. Validation of the mineral analysis was conducted using soybean meal (GBW10013; National Institute of Standards and Technology, Beijing, China) as a standard reference material. The tibial osteoblastic P retention rate was calculated as follows:
where V1 is total volume (ml) of the added fresh medium, C1 is total P content (mmol/L) in the fresh medium, V2 is total volume (ml) of the pooled old medium, and C2 is total P content (mmol/L) in the old medium.

The morphology and size distribution of Pt/SiO₂ catalyst were investigated by transmission electron microscopy (TEM; ARM 200 F, JEOL) at 200 kV. The catalyst loading was determined using inductively coupled plasma optical emission spectroscopy (ICP-OES; 5110 ICP-OES; Agilent). The catalyst microstructure was measured by X-ray diffractometer (XRD; D2 Phaser, Bruker) with a Cu Kα (1.5406 Å) radiation source (10 mA, 30 kV). The chemical states of catalyst was investigated by X-ray photoelectron spectroscopy (XPS; Nexsa, Thermo Fisher Scientific) using an Al Kα (hν = 1486.7 eV) X-ray source. All core-level spectrum was calibrated by silicon oxide (Si⁴⁺) in Si 2p to 103.5 eV. The XPS sample pretreatments were performed in the DRIFTS reactor and resultant catalyst powder was pressed onto a carbon tape mounted on a Si wafer for each XPS measurement. The N₂ adsorption isotherm at 77 K of the SiO₂ support was collected by surface characterisation analyser (3Flex, Micromeritics). The steady-state flow catalytic activity was measured in a home-built ambient pressure flow reactor that has been previously described^{77 (link)} with all gas mixtures reported balanced in Ar (See Supplementary IV).

MoFeP was diluted to 0.05 to 0.5 mg/mL in a solution containing 6 M guanidine hydrochloride to denature the protein and 2% nitric acid to liberate the metal ions and precipitate the polypeptide. The solution was clarified by centrifugation. Metal content of the respective proteins was measured on an Agilent 5110 ICP-OES at 238.2 nm for Fe and 203.8 nm for Mo. The metal content was calculated based on standard curves for Fe and Mo that spanned 0 to 500 ppm.

W levels in laboratory media and filtered GBS spring water were measured using ICP-MS after the addition of nitric acid (OPTIMA grade, Fisher Chemical, Fair Lawn, NJ, USA) to 1% final concentration at Huffman Hazen Laboratories (Golden, CO, USA). W levels in filtered GBS spring water were also measured using inductively coupled plasma optical emission spectroscopy (ICP-OES) with an Agilent 5110 ICP-OES (Santa Clara, CA, USA) and dilutions of a W calibration standard (PLW9-2Y, SPEX CertiPrep, Metuchen, NJ, USA). Nitric acid was added to samples and standards to a final concentration of 1% before analysis, and optical emission at 207.91 nm was used for W quantification. Broad trace element analysis by ICP-MS on GBS spring water and media was performed on samples prepared as described above at the Analytical Chemistry Laboratory of New Mexico Bureau of Geology and Mineral Resources, New Mexico Institute of Mining and Technology.

Elemental concentration of P was analyzed on a dry-mass basis using Inductively Coupled Plasma Optical Emission Spectrometry (Agilent 5110 ICP-OES, USA). The dried samples were divided into 3 subsamples to get the minimal dry mass required for the chemical analysis in order to quantify P content.