Thread Content
This issue mainly introduces the preparation methods for 73 types of atomic absorption standard stock solutions and the storage techniques for these standard stock solutions. Storage of standard solutions: Preventing loss is an important issue in the preparation of standard solutions and samples. For solutions with low concentrations (≤1μg·mL-1), it is best not to use them for more than 1–2 days. The degree and rate of loss are related to the concentration of the standard solution, the acidity of the storage solution, and the material of the container. Robinson studied the loss rates of Sc, Fe, Zn, Co, Sr, Rb, Ag, In, Sb, and U in seawater stored in either hard glass bottles or plastic bottles. He found that in unacidified seawater, elements such as In, Sc, Fe, Ag, and U were lost within just a few days, whereas in seawater acidified to pH 1.5 with hydrochloric acid, no loss of these elements occurred except for Sc. When determining Ag, Pb, Cd, Zn, and Ni in rain, snow, and hail, Sui Ciumupole investigated the adsorption of these elements by various containers such as silica-borosilicate glass, polyethylene, and polypropylene, and found that sample solutions acidified to pH=2 with nitric acid stored in polyethylene containers were satisfactory. As a stock solution, a solution with a high concentration (for example, above 1 mg·mL/1) should be prepared. Inorganic stock solutions or sample solutions are placed in polyethylene containers, maintained at the required acidity, and stored in a clean, cool, and dark place. During storage, organic solutions should be kept in a clean, cool, and dark place. It should also be avoided from coming into direct contact with plastics, bakelite bottle caps, etc. Methods for preparing 73 AAS standard stock solutions: 1. Silver (Ag): 1) Weigh 1.5750 g of high-purity silver nitrate (AgNO3) in a beaker and dissolve it in 50 mL of water. Then transfer it to a 1000 mL brown polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The silver concentration is 1 mg·mL/1. (2) Weigh 1.0000 g of high-purity metallic silver into a beaker. Dissolve in 20 mL of (1+1) HNO3. Transfer to a 1000 mL brown polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The silver concentration is 1 mg·mL/1. 2. Aluminum (Al): 1) Weigh 1.7590 g of high-purity potassium aluminum sulfate and dissolve it in water in a polytetrafluoroethylene beaker. Transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The aluminum concentration is 1 mg·mL/1. 2) Weigh 3.0000 g of high-purity metallic aluminum into a polytetrafluoroethylene beaker, add 25 mL of HCl, and add a few drops of HNO3 to facilitate dissolution. Transfer the mixture to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The aluminum concentration is 1 mg·mL/1. 3. Arsenic (As): 1) Weigh 1.3203 g of high-purity arsenic trioxide (As2O3) and dissolve it in a polytetrafluoroethylene beaker in 25 mL of 200 g·L-1 KOH solution. Add a few drops of phenolphthalein, and neutralize with 20% HNO3 (by volume) until the phenolphthalein changes from red to colorless. Then, transfer it to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The arsenic concentration is 1 mg·mL/1. (2) Weigh 1.3203 g of high-purity arsenic trioxide (As2O3), dissolve it in a beaker using 50 mL of HCl, then transfer the solution to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The arsenic concentration is 1 mg·mL/1. 4. Gold (Au): 0.1000 g of high-purity gold was weighed and placed in a beaker, where it was dissolved in 10 mL of aqua regia. The mixture was heated until it dried out, after which 10 mL of HCl was added. The solution was then transferred to a 100 mL polyethylene volumetric flask using 5% HCl (by volume), and diluted to the mark before being mixed thoroughly. The gold concentration is 1 mg·mL/1. 5. Boron (B): Weigh 0.5718 g of high-purity boric acid (H3BO3) that has been dried at 50°C and place it in a beaker. Add 10 mL of HNO3 and dissolve it by warming the mixture. Transfer the solution to a 100 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The boron concentration is 1 mg·mL/1. 6. Barium (Ba): Weighed 1.7793 g of high-purity barium chloride (BaCl2·2H2O) in a beaker, dissolved it in water, transferred the solution to a 100 mL polyethylene volumetric flask using 5% HNO3 (by volume), diluted to the mark, and mixed well. The concentration of barium is 1 mg·mL/1. 7. Beryllium (Be): 1) Weigh 19.6418 g of high-purity beryllium sulfate (BeSO4·4H2O) in a beaker, dissolve it in water, and transfer the solution to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume). Dilute to the mark and mix well. The beryllium concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of high-purity beryllium metal into a beaker, dissolve it in 10 mL of (1+1)HCl, and transfer it to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume). Dilute to the mark and shake well. The beryllium concentration is 1 mg·mL/1. 8. Bismuth (Bi) 1) Weigh 2.3210 g of high-purity bismuth nitrate in a beaker. Dissolve by adding 100 mL of 7 mol·L-1 HNO3, and transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume). Dilute to the mark and shake well. The bismuth concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of highly pure bismuth metal into a beaker. Add 10 mL of (1+1) HNO3 to dissolve it, transfer the mixture to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The bismuth concentration is 1 mg·mL/1. 9. Bromine (Br): 1.4890 g of high-purity potassium bromide (KBr), dried to a constant weight at 105°C, was placed in a beaker, dissolved in water, transferred to a 1000 mL brown polyethylene volumetric flask with water, and diluted to the mark before being mixed thoroughly. The bromine concentration is 1 mg·mL/1. 10. Calcium (Ca): Weigh 2.4970 g of high-purity calcium carbonate (CaCO3) that has been dried to a constant weight at 105–110°C, and place it in a beaker; add 100 mL of water. Then, 10 mL of HNO3 is slowly added to completely dissolve CaCO3, and heating is used to drive off CO2. After cooling, transfer it to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. For a calcium concentration of 1 mg·mL⁻¹: 11. Cadmium (Cd): 1) Weigh 1.1423 g of high-purity cadmium oxide (CdO) into a beaker, and add 20 mL of 7 mol·L⁻¹ HNO₃ to dissolve it. Transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The cadmium concentration is 1 mg·mL/1. 2) Weigh 2.4323 g of high-purity cadmium chloride (CdCl2·5H2O) into a beaker, dissolve it in water, transfer the solution to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The cadmium concentration is 1 mg·mL/1. 12. Cerium (Ce): Weigh 3.9118 g of high-purity ammonium cerium nitrate and dissolve it in a beaker. Transfer the solution to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The cerium concentration is 1 mg·mL/1. 13. Chlorine (Cl): 1.6485 g of spectroscopically pure sodium chloride (NaCl), which had been burned at 500°C for 15 minutes and then cooled in a desiccator, was dissolved in water in a beaker. Transfer to a 1000 mL polyethylene volumetric flask with water, dilute to the mark, and mix well. The chlorine concentration is 1 mg·mL/1. 14. Cobalt (Co): 1) Weigh 2.6289 g of anhydrous cobalt sulfate (CoSO4), which was calcined at 500–550°C until a constant weight was reached, and place it in a beaker; then dissolve it in water. Transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The cobalt concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of high-purity metallic cobalt into a beaker, dissolve it in 10 mL of (1+1)HCl, transfer it to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The cobalt concentration is 1 mg·mL/1. 15. Chromium (Cr): 1) Weigh 3.7349 g of high-purity potassium chromate (K2CrO4), which has been dried at 105°C until a constant weight is reached, and place it in a beaker. Dissolve it in water, then transfer the solution to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), and dilute to the mark. Stir well. The chromium concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of high-purity metallic chromium into a beaker. Add 50 mL of HCl to dissolve it, transfer the mixture to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The chromium concentration is 1 mg·mL/1. 16. Cesium (Cs): 1.2671 g of it was placed in a beaker along with high-purity cesium chloride (CsCl) dried at 110°C. It was dissolved in water, then transferred to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), and diluted to the mark before being mixed thoroughly. The cesium concentration is 1 mg·mL/1. 17. Copper (Cu): 1) Weigh 3.9270 g of high-purity copper sulfate (CuSO4·5H2O) in a beaker, dissolve it in water, transfer the solution to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The copper concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of high-purity copper into a beaker, dissolve it in 10 mL of (1+1) HNO3, then transfer it to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The copper concentration is 1 mg·mL/1. 18. Dysprosium (Dy): 1.1477 g of high-purity dysprosium trioxide (Dy2O3) was weighed and placed in a beaker, where it was dissolved in 50 mL of 6 mol·L-1 HCl. Afterwards, the solution was transferred to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), diluted to the mark, and mixed thoroughly. The dysprosium concentration is 1 mg·mL/1. 19. Erbium (Er): 1.1435 g of high-purity erbium oxide (Er2O3) was weighed and placed in a beaker. It was dissolved in 50 mL of 6 mol·L-1 HCl, then transferred to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), and diluted to the mark before being mixed thoroughly. The erbium concentration is 1 mg·mL/1. 20. Europium (Eu): 1.1579 g of high-purity europium dioxide (Eu2O3) was weighed and placed in a beaker. 50 mL of 6 mol·L-1 HCl was added to dissolve it, and the solution was transferred to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume). The solution was then diluted to the mark and mixed thoroughly. The europium concentration is 1 mg·mL/1. 21. Fluorine (F): 2.1000 g of high-purity sodium fluoride (NaF), which had been burned at 500°C for 15 minutes and then cooled in a desiccator, was placed in a polytetrafluoroethylene beaker and dissolved in water. Transfer to a 1000 mL polyethylene volumetric flask with water, dilute to the mark, and mix well. The fluoride concentration is 1 mg·mL/1. 22. Iron (Fe): 1) Weigh 8.6948 g of high-purity ammonium ferric sulfate and dissolve it in a beaker with water. Add 2.5 mL of HNO3, transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The iron concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of high-purity metallic iron into a beaker, add 50 mL of (1+1)HNO3 to dissolve it, transfer the mixture to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The iron concentration is 1 mg·mL/1. 23. Gallium (Ga): 1) Weigh 1.3442 g of high-purity gallium dioxide (Ga2O3) into a beaker, add 30 mL of (1+1) HCl, and heat it in a water bath to dissolve it. Transfer to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The gallium concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of high-purity gallium metal into a beaker, dissolve it in 10 mL of aqua regia, transfer it to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The gallium concentration is 1 mg·mL/1. 24. Gadolinium (Gd): 1.1526 g of high-purity gadolinium oxide (Gd2O3) was weighed and placed in a beaker. 50 mL of 6 mol·L-1 HCl was added to dissolve it, and the solution was transferred to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume). The solution was then diluted to the mark and mixed thoroughly. The gadolinium concentration is 1 mg·mL/1. 25. Germanium (Ge): 1) Weigh 1.4408 g of high-purity germanium dioxide (GeO2) in a beaker, add 50 g of oxalic acid dissolved in 100 mL of water, transfer the mixture to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The germanium concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of high-purity germanium metal and place it in a polytetrafluoroethylene beaker; add 5 mL of HF, then add a few drops of HNO3 until complete dissolution is achieved. Transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The germanium concentration is 1 mg·mL/1. 26. Hafnium (Hf): 1.0000 g of high-purity hafnium metal was weighed and placed in a PTFE beaker; 5 mL of HF was added, followed by the gradual addition of HNO3 until complete dissolution was achieved. Transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The hafnium concentration is 1 mg·mL/1. 27. Mercury (Hg): 1) Weigh 1.0798 g of high-purity mercuric oxide (HgO) in a beaker, and add (1+1) HCl drop by drop until complete dissolution. Transfer to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The mercury concentration is 1 mg·mL/1. 2) Weigh 1.3540 g of high-purity mercuric chloride (HgCl2) in a beaker, dissolve it in water, transfer it to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The mercury concentration is 1 mg·mL/1. 3) Weigh 1.0000 g of high-purity mercury in a beaker, dissolve it in 20 mL of 7 mol·L-1 HNO3, transfer it to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The mercury concentration is 1 mg·mL/1. 28. Holmium (Ho): Weigh 1.1455 g of high-purity holmium oxide (Ho2O3) into a beaker, and add 50 mL of 6 mol·L-1 HCl to dissolve it. Transfer to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The holmium concentration is 1 mg·mL^-1. 29. Iodine (I): Weigh 1.3080 g of pure potassium iodide (KI) in a beaker, dissolve it in water, transfer the solution to a 1000 mL brown polyethylene volumetric flask, dilute to the mark, and mix well. The iodine concentration is 1 mg·mL/1. 30. Indium (In): 1.0000 g of high-purity indium metal was weighed and placed in a beaker; 10 mL of (1+1)HCl was added, along with a few drops of HNO3, and the mixture was warmed until all the indium had dissolved. Transfer to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The indium concentration is 1 mg·mL/1. 31. Iridium (Ir): 2.3892 g of high-purity ammonium chloroiridate was weighed and placed in a beaker; it was dissolved using 10% HCl (by volume). The solution was then transferred to a 1000 mL polyethylene volumetric flask using 10% HCl, and diluted to the mark before being mixed thoroughly. The iridium concentration is 1 mg·mL/1. 32. Potassium (K): 1.9068 g of high-purity potassium chloride (KCl), which has been burned at 500–600°C until a constant weight is reached, was placed in a beaker. It was dissolved in water, then transferred to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), and the solution was diluted to the mark before being mixed thoroughly. The potassium concentration is 1 mg·mL/1. 33. Lanthanum (La): Weigh 1.1728 g of high-purity lanthanum trioxide (La2O3) into a beaker and add 30 mL of water. Add 25 mL of HCl slowly and dissolve. Transfer to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The concentration of lanthanum is 1 mg·mL/1. 34. Lithium (Li): 1) Weigh 6.1145 g of high-purity lithium chloride (LiCl) and dissolve it in water in a beaker. Transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The lithium concentration is 1 mg·mL/1. 2) Weigh 5.3228 g of extra pure lithium carbonate (Li2CO3) into a beaker, and add 30 mL of water. Add HCl dropwise until completely dissolved; heat to drive off CO2. After cooling, transfer the solution to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The lithium concentration is: 1 mg·mL/1. 35. Lutetium (Lu): 1) Weigh 1.1372 g of high-purity lutetium trioxide (Lu2O3) in a beaker, add 30 mL of water, then slowly add (1+1)HCl until complete dissolution. Transfer the solution to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The lutetium concentration is 1 mg·mL/1. 2) Weigh 1.6079 g of high-purity lutetium chloride (LuCl3) in a beaker, dissolve it in water, and transfer it to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), then dilute to the mark. Shake well. The lutetium concentration is 1 mg·mL/1. 36. Magnesium (Mg): 1) Weigh 1.6583 g of it and burn it at 800°C until a constant weight is reached; the resulting high-purity magnesium oxide (MgO) is placed in a beaker. Add 20 mL of water and then slowly add HCl to dissolve it completely. Transfer to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The magnesium concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of spectroscopically pure magnesium metal into a beaker, dissolve it in a small amount of 6 mol·L⁻¹ HCl, then transfer the solution to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume). Dilute to the mark and mix well. The magnesium concentration is 1 mg·mL/1. 37. Manganese (Mn): 1) Weigh 1.5825 g of high-purity manganese dioxide (MnO2) in a beaker. Dissolve in about 50 mL of HCl, heat and evaporate to dryness; dissolve the residue in HNO3. Transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The manganese concentration is 1 mg·mL/1. 2) Weigh 2.7474 g of extra-pure anhydrous manganese sulfate (MnSO4) that has been calcined at 400–500°C until a constant weight is achieved, and place it in a beaker; then dissolve it in water. Transfer to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The manganese concentration is 1 mg·mL/1. 3) Weigh 1.0000 g of high-purity metallic manganese, place it in a beaker, and add (1+1)HNO3 to dissolve it. Then transfer it to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The manganese concentration is 1 mg·mL/1. 38. Molybdenum (Mo): 1) Weigh 1.5003 g of high-purity molybdenum trioxide (MoO3) into a polytetrafluoroethylene beaker, and add 100 mL of 2 mol·L-1 NH3·H2O to dissolve it. Then it is transferred to a 1000 mL polyethylene volumetric flask using 1% NH3·H2O (by volume), diluted to the mark and shaken well, resulting in a molybdenum concentration of 1 mg·mL^-1. 2) Weigh 1.8398 g of high-purity ammonium molybdate ((NH4)3·4H2O) into a polytetrafluoroethylene beaker, transfer it to a 1000 mL polyethylene volumetric flask using 1% NH3·H2O (by volume), dilute to the mark, and mix well. The molybdenum concentration is: 1 mg·mL/1. 39. Sodium (Na): 2.5420 g of high-purity sodium chloride (NaCl) dried at 105°C was weighed and dissolved in water in a polytetrafluoroethylene beaker. Transfer to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The sodium concentration is: 1 mg·mL/1. 40. Niobium (Nb): 1) Weigh 1.0000 g of high-purity metallic niobium and place it in a polytetrafluoroethylene beaker; add 5 mL of HF, then drop in HNO3 until the niobium is completely dissolved. Transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The niobium concentration is 1 mg·mL/1. 2) Weigh 1.1305 g of high-purity niobium pentoxide (Nb2O5) and 4 g of powdered potassium pyrosulfate; place both in a platinum crucible and melt them at 800°C for 10 minutes. After removal and cooling, dissolve the mixture using 20 mL of a 150 g·L/1 solution of tartaric acid (by volume). Transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The niobium concentration is 1 mg·mL/1. 41. Neodymium (Nd): 1.1661 g of high-purity neodymium oxide (Nd2O3) was weighed and placed in a beaker. Dissolve by adding 6 mol·L-1 HCl. Then transfer it to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The neodymium concentration is 1 mg·mL/1. 42. Nickel (Ni): 1.0000 g of high-purity metallic nickel was weighed and placed in a beaker, after which (1+1) HNO3 was added to dissolve it. Then transfer it to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The nickel concentration is 1 mg·mL/1. 43. Osmium (Os) 1) Weigh 2.2881 g of highly pure ammonium osmate chloride in a beaker and dissolve it using 20 mL of 6 mol·L-1 HCl. Transfer to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The osmium concentration is 1 mg·mL/1. 2) Weigh 1.3365 g of high-purity osmium oxide (OsO4) in a beaker, dissolve it in 5% HNO3 (by volume), transfer it to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The osmium concentration is 1 mg·mL/1. 44. Phosphorus (P): Weigh 4.2608 g of high-purity diammonium hydrogen phosphate and dissolve it in a beaker with water. Transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The phosphorus concentration is 1 mg·mL/1. 45. Lead (Pb): 1) Weigh 1.5985 g of high-purity lead nitrate, Pb(NO3)2, into a beaker. Add 5% HNO3 (by volume) and dissolve. Transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The lead concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of high-purity metallic lead into a beaker and add a small amount of 7 mol·L-1 HNO3 to dissolve it. Transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The lead concentration is 1 mg·mL/1. 46. Palladium (Pd): 1) Weigh 1.6672 g of high-purity palladium chloride (PdCl2) in a beaker, and add 30 mL of 6 mol·L-1 HCl to dissolve it. Transfer to a 1000 mL polyethylene volumetric flask using 10% HCl (by volume), dilute to the mark, and mix well. The palladium concentration is 1 mg·mL/1. 2) Weigh 0.1000 g of high-purity palladium metal into a beaker and dissolve it using 25 mL of freshly prepared aqua regia. After heating and evaporation, add 5 mL of HCl and 25 mL of aqua regia, and heat until complete dissolution. Transfer to a 100 mL polyethylene volumetric flask using 10% HCl (by volume), dilute to the mark, and mix well. The palladium concentration is 1 mg·mL/1. 47. Praseodymium (Pr): 1.1703 g of high-purity praseodymium oxide (Pr2O3) was weighed and placed in a beaker. 30 mL of 6 mol·L-1 HCl was added to dissolve it, after which the mixture was transferred to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), diluted to the mark, and mixed thoroughly. The praseodymium concentration is 1 mg·mL/1. 48. Platinum (Pt): 2.2764 g of high-purity ammonium chloroplatinate was weighed and placed in a beaker, where it was dissolved in water. The solution was then transferred to a 1000 mL polyethylene volumetric flask using 10% HNO3 (by volume), and diluted to the mark before being mixed thoroughly. The platinum concentration is 1 mg·mL/1. 2) Weigh 2.1286 g of high-purity potassium chloroplatinate (K2PtCl4) and add 20 mL of 10% HNO3 (by volume) in a beaker to dissolve it. Transfer to a 1000 mL polyethylene volumetric flask using 10% HNO3 (by volume), dilute to the mark, and mix well. The platinum concentration is 1 mg·mL/1. 3) Weigh 0.1000 g of high-purity metallic platinum into a beaker, dissolve it in 25 mL of freshly prepared aqua regia, heat and evaporate until just dryness is reached. Add 5 mL of HCl and 0.1 g of NaCl, then evaporate to dryness; the residue is dissolved in 20 mL of (1+1) HCl. Transfer to a 100 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The platinum concentration is: 1 mg·mL/1. 49. Rubidium (Rb): 1.4154 g of high-purity rubidium chloride (RbCl) was weighed and dissolved in a beaker with water. Transfer to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The rubidium concentration is 1 mg·mL/1. 50. Rhenium (Re): 1) Weigh 1.5537 g of high-purity potassium rhenate (KReO4) in a beaker and dissolve it in 200 mL of water. Then transfer it to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The rhenium concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of high-purity metallic rhenium into a beaker, add 20 mL of (1+1) HCl, and add H2O2 drop by drop to ensure complete decomposition of the rhenium. Add a small amount of water and bring to a boil to remove the H2O2, then cool. Transfer to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The rhenium concentration is 1 mg·mL/1. 51. Lanthanum (Rh): 0.3857 g of high-purity ammonium chlorolanthanate was weighed into a beaker. Add 10 mL of (1+1)HCl to dissolve it. Then transfer it to a 100 mL polyethylene volumetric flask using 10% HCl (by volume), dilute to the mark, and mix well. The lutetium concentration is 1 mg·mL/1. 52. Ruthenium (Ru): 1) Weigh 0.2054 g of high-purity ruthenium chloride (RuCl3) in a beaker. Dissolved in 20% HCl (volume fraction). Then transfer it to a 100 mL polyethylene volumetric flask using 20% HCl (by volume), dilute to the mark, and mix well. The ruthenium concentration is 1 mg·mL/1. 2) Weigh 1.3165 g of high-purity ruthenium dioxide (RuO2) into a beaker, add 15 mL of HCl to dissolve it, then transfer the mixture to a 1000 mL polyethylene volumetric flask using 20% HCl (by volume), and dilute to the mark while mixing well. The concentration of ruthenium is 1 mg·mL^-1. 53. Sulfur (S): 4.4304 g of anhydrous, reagent-grade sodium sulfate (Na2SO4) was weighed and placed in a beaker, where it was dissolved in water. Transfer to a 1000 mL polyethylene volumetric flask with water, dilute to the mark, and mix well. The sulfur concentration is 1 mg·mL^-1. 54. Antimony (Sb): 1) Weigh 2.742 g of high-purity potassium antimonate tartrate (KSbC4H4O7·0.5H2O) into a beaker, dissolve it in water, transfer the solution to a 1000 mL polyethylene volumetric flask using 10% HNO3 (by volume), and dilute to the mark while shaking well. The antimony concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of high-purity antimony metal into a beaker, add 10 mL of HNO3 and 5 mL of HCl to dissolve it, then transfer the mixture to a 1000 mL polyethylene volumetric flask using 10% HNO3 (by volume), dilute to the mark, and mix well. The antimony concentration is 1 mg·mL/1. 55. Scandium (Sc): 1.5339 g of high-purity scandium oxide (Sc2O3) was weighed and placed in a beaker; 50 mL of 6 mol·L-1 HCl was added to dissolve it. The solution was then transferred to a 1000 mL polyethylene volumetric flask using 5% HCl by volume, diluted to the mark, and mixed thoroughly. The scandium concentration is 1 mg·mL/1. 56. Selenium (Se): 1) Weigh 1.4053 g of high-purity selenium dioxide (SeO2) in a beaker, dissolve it in HCl, transfer the solution to a 1000 mL polyethylene volumetric flask using 10% HCl (by volume), dilute to the mark, and mix well. The selenium concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of high-purity metallic selenium in a beaker and dissolve it with HNO3. Heat and evaporate to dryness, add 2 mL of water, and then evaporate to dryness again. Repeat 2–3 times, then dissolve the residue in 10% HCl (by volume). Transfer to a 1000 mL polyethylene volumetric flask using 10% HCl (by volume), dilute to the mark, and mix well. The selenium concentration is 1 mg·mL/1. 57. Silicon (Si): 1) Weigh 5.0574 g of high-purity sodium silicate (Na2SiO3·9H2O) into a beaker. Add 300 mL of water to dissolve it, add HCl to adjust the pH to ≈5, transfer it to a 500 mL polyethylene volumetric flask with water, dilute to the mark, and mix well. The silicon concentration is 1 mg·mL/1. 2) Weigh 2.1394 g of high-purity SiO2 into a platinum crucible, add 4.6 g of Na2CO3 and mix well. Keep it molten in a furnace at 1000°C for 20 minutes, then cool it. Place it in a polytetrafluoroethylene beaker, extract it with warm water, and finally transfer it to a 1000 mL polyethylene volumetric flask using water. Dilute to the mark and shake well. The silicon concentration is 1 mg·mL/1. Note: This solution contains 2 mg·mL/1 of sodium. 58. Samarium (Sm): 1.1596 g of highly pure samarium dioxide (Sm2O3) was weighed and placed in a beaker. 50 mL of 6 mol·L-1 HCl was added to dissolve it, after which the solution was transferred to a 1000 mL polyethylene volumetric flask using 10% HCl (by volume), diluted to the mark, and mixed thoroughly. The samarium concentration is 1 mg·mL^-1. 59. Tin (Sn): 1.0000 g of high-purity metallic tin was weighed and placed in a beaker; 100 mL of HCl was added to dissolve it. The solution was then transferred to a 1000 mL polyethylene volumetric flask using 10% HCl (by volume), and diluted to the mark before being mixed thoroughly. The tin concentration is 1 mg·mL/1. Note: The standard series solutions for tin must be prepared by diluting them with a 10% HCl solution (by volume). 60. Strontium (Sr): 3.0429 g of high-purity strontium chloride (SrCl2·6H2O) was weighed and placed in a beaker, where it was dissolved in water. The solution was then transferred to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), diluted to the mark, and mixed thoroughly. The tin concentration is 1 mg·mL/1. 61. Tantalum (Ta): 1) Weigh 1.9809 g of high-purity tantalum pentoxide (Ta2O5) in a beaker, and dissolve it by adding (1+1) HNO3. Transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The tantalum concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of highly pure tantalum metal into a polytetrafluoroethylene beaker, add 50 mL of HF, and add HNO3 drop by drop until complete dissolution occurs. Transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The tantalum concentration is 1 mg·mL/1. 62. Terbium (Tb): 1) Weigh 1.6701 g of high-purity terbium chloride (TbCl3) in a beaker and dissolve it with HCl. Transfer to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The terbium concentration is 1 mg·mL/1. 2) Weigh 1.1762 g of high-purity tetraterbium heptoxide (Tb4O7) into a beaker, add 50 mL of 6 mol·L-1 HCl to dissolve it, and then transfer the solution to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume). Dilute to the mark and shake well. The terbium concentration is 1 mg·mL/1. 63. Tellurium (Te): 1.0000 g of high-purity metallic tellurium was weighed and placed in a beaker. HNO3 was added slowly, followed by 50 mL of water; then HCl was added to dissolve the precipitate. Nitrogen oxides were removed by heating, and after cooling, the solution was transferred to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume). Dilute to the mark and shake well. The tellurium concentration is 1 mg·mL/1. 64. Thorium (Th): 2.3793 g of high-purity thorium nitrate was weighed and placed in a beaker; it was dissolved in water. 5 mL of HNO3 was added, and the solution was transferred to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), after which it was diluted to the mark and mixed thoroughly. The thorium concentration is 1 mg·mL/1. 65. Titanium (Ti): 1) Weigh 1.6683 g of high-purity titanium dioxide (TiO2) into a porcelain crucible, add 2 g of potassium pyrosulfate, melt it for a few minutes, then cool it. In a polytetrafluoroethylene beaker, dissolve it in sulfuric acid at a concentration of 0.5 mol·L⁻¹. Transfer to a 1000 mL polyethylene volumetric flask using 10% HNO3 (by volume), dilute to the mark, and mix well. The titanium concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of high-purity metallic titanium into a beaker, add 100 mL of (1+1) HCl (by volume), and heat to dissolve it. After cooling, transfer the solution to a 1000 mL polyethylene volumetric flask using 10% HCl (by volume), dilute to the mark, and mix well. The titanium concentration is 1 mg·mL/1. 66. Thallium (Tl): 1) Weigh 1.1737 g of high-purity thallium chloride (TlCl) in a beaker, dissolve it in 5 mL of HNO3, transfer the solution to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The thallium concentration is 1 mg·mL/1. 2) Weigh 1.3034 g of high-purity thallium nitrate (TlNO3) in a beaker, dissolve it in water, transfer it to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The thallium concentration is 1 mg·mL/1. 3) Weigh 1.2349 g of high-purity thallium sulfate (Tl2SO4) in a beaker, dissolve it in water, transfer it to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The thallium concentration is 1 mg·mL/1. 67. Thulium (Tm): 1.1421 g of high-purity thulium oxide (Tm2O3) was weighed and placed in a beaker; 50 mL of 6 mol·L-1 HCl was added to dissolve it. The solution was then transferred to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), diluted to the mark, and mixed thoroughly. The thulium concentration is 1 mg·mL/1. 68. Vanadium (V): 1) Weigh 2.2956 g of high-purity ammonium vanadate (NH4VO3) in a beaker, add 10 mL of HNO3 to dissolve it, transfer the mixture to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The vanadium concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of high-purity vanadium metal into a beaker, add 10 mL of HNO3 to dissolve it, then transfer the mixture to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The vanadium concentration is 1 mg·mL/1. 69. Tungsten (W): 1) Weigh 1.7941 g of high-purity sodium tungstate (Na2WO4·H2O) in a polytetrafluoroethylene beaker, dissolve it in 200 mL of water, add 100 mL of 100 g·L-1 NaOH solution, then transfer the mixture to a 1000 mL polyethylene volumetric flask and dilute to the mark while stirring. The tungsten concentration is 1 mg·mL/1. 2) Weigh 1.2611 g of high-purity tungsten trioxide (WO3), which had been dried at 100–110°C for 1 hour and then cooled, and place it in a polytetrafluoroethylene beaker. Add 30–40 mL of 200 g/L NaOH solution and heat to dissolve it, followed by cooling. Transfer to a 1000 mL polyethylene volumetric flask with water, dilute to the mark, and mix well. The tungsten concentration is 1 mg·mL/1. 70. Yttrium (Y): 1.2698 g of high-purity yttrium oxide (Y2O3) was weighed and placed in a beaker, to which 50 mL of 6 mol·L-1 HCl was added for dissolution. Then transfer it to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The yttrium concentration is 1 mg·mL/1. 71. Ytterbium (Yb): 1) Weigh 1.6152 g of high-purity ytterbium chloride (YbCl3) in a beaker and dissolve it with HNO3. Transfer to a 1000 mL polyethylene volumetric flask using 5% HNO3 (by volume), dilute to the mark, and mix well. The ytterbium concentration is 1 mg·mL^-1. 2) Weigh 1.1387 g of high-purity yttrium oxide (Yb2O3) into a beaker, and add 50 mL of 6 mol·L-1 HCl to dissolve it. Then transfer it to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The ytterbium concentration is 1 mg·mL^-1. 72. Zinc (Zn): 1) Weigh 1.2447 g of high-purity zinc oxide (ZnO) that has been burned at 1000°C until a constant weight is reached. Place it in a beaker, add 100 mL of water and 20 mL of HCl to dissolve it. Transfer the mixture to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), then dilute to the mark and mix well. The zinc concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of high-purity metallic zinc in a beaker, dissolve it with (1+1) HCl, then transfer it to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The zinc concentration is 1 mg·mL/1. 73. Zirconium (Zr): 1) Weigh 3.5323 g of high-purity zirconium oxychloride (ZrOCl2·H2O) into a beaker, add 50 mL of 6 mol·L-1 HCl and heat to dissolve it. Transfer the solution to a 1000 mL polyethylene volumetric flask using 5% HCl (by volume), dilute to the mark, and mix well. The zirconium concentration is 1 mg·mL/1. 2) Weigh 1.0000 g of high-purity zirconium metal in a polytetrafluoroethylene beaker, moisten it with 10 mL of water, add 1 mL of HF drop by drop. Once the zirconium has completely dissolved, transfer the solution to a 1000 mL polyethylene volumetric flask using 2% HF (by volume), dilute to the mark, and mix well. The zirconium concentration is 1 mg·mL/1.