[American Bull Fertilizers Group] - Standard for determination of soil total phosphorus

The total phosphorus content in soil represents the overall phosphorus reserve, encompassing both organic and inorganic forms. However, most of the phosphorus in the soil exists in a slow-release form, which means that the total phosphorus level alone cannot be used as an accurate indicator of phosphorus availability to plants. A high total phosphorus content does not necessarily mean that the soil has sufficient available phosphorus, and conversely, low total phosphorus levels may indicate limited phosphorus supply. Therefore, while understanding the total phosphorus storage is useful, it only provides a general reference for agricultural practices. To determine soil total phosphorus, two common methods are employed: alkali fusion and acid digestion. The alkali fusion method, particularly using sodium carbonate (Na₂CO₃) at high temperatures, offers high accuracy and complete decomposition of phosphorus compounds. However, this method requires a platinum crucible, making it unsuitable for routine analysis due to cost and complexity. On the other hand, the acid digestion method using sulfuric acid (H₂SO₄) and perchloric acid (HClO₄) is more commonly used. This approach works well for calcareous soils but may not fully decompose acidic soils, leading to slightly lower results. Phosphorus in the digested solution is typically analyzed using the molybdenum blue colorimetric method. Common reagents include ammonium molybdate, potassium antimony tartrate, ascorbic acid, and 1,2,4-aminonaphthol sulfonic acid. Among these, the "molybdenum antimony" reagent is widely used in China due to its simplicity, stable color development, and tolerance to interfering ions. **1. Acid-Soluble Molybdenum Antimony Colorimetric Method** **(1) Procedure Overview:** Under high-temperature conditions, phosphorus-containing minerals and organic compounds in the soil are completely decomposed using concentrated sulfuric acid (H₂SO₄) and strong oxidizing agent perchloric acid (HClO₄). All phosphorus is converted into soluble orthophosphate, which is then determined by the molybdenum antimony colorimetric method. **(2) Main Equipment:** Spectrophotometer, 2KVA electric furnace, 3KVA voltage regulator transformer. **(3) Reagents:** A. Concentrated H₂SO₄ (secondary grade). B. HClO₄ (70–72%, secondary grade). C. Molybdenum antimony stock solution: Prepare by mixing H₂SO₄ with ammonium molybdate and potassium antimony tartrate. D. Molybdenum antimony reagent: Ascorbic acid dissolved in the stock solution. E. Dinitrophenol indicator: Used to detect pH changes during titration. F. 5 ppm P standard solution: Prepared from KH₂PO₄ and diluted appropriately. **(4) Operational Steps:** - **Sample Preparation:** Weigh 1g of dried soil, add H₂SO₄ and HClO₄, and heat until fumes subside. Cool and dilute to 100 ml. - **Analysis:** Take 2–10 ml of the test solution, adjust pH, add reagents, and measure absorbance at 700 nm after 30 minutes. - **Calibration Curve:** Prepare standards at 0, 0.1, 0.2, ..., 0.6 ppm P and plot absorbance vs. concentration. **2. Alkali Fusion - Molybdenum Antimony Colorimetric Method** **(1) Procedure Overview:** Soil samples are melted with Na₂CO₃ at high temperatures, converting insoluble phosphates and organic phosphorus into soluble orthophosphates. The melt is then dissolved in dilute sulfuric acid and analyzed using the same colorimetric method. **(2) Main Equipment:** Platinum crucible, high-temperature furnace, spectrophotometer. **(3) Reagents:** A. Anhydrous Na₂CO₃ (ground to 250 microns). B. 6 mol/L H₂SO₄. Other reagents are similar to those used in the acid digestion method. **(4) Operational Steps:** - Weigh 0.25g of soil, mix with Na₂CO₃, and melt at 900–920°C for 20 minutes. - Dissolve the melt in diluted H₂SO₄, filter, and analyze the filtrate using the molybdenum antimony method. **(5) Result Calculation:** Results are calculated based on the calibration curve obtained from the standard solutions. Both methods require blank tests to eliminate background interference. Overall, choosing the appropriate method depends on the soil type, available equipment, and analytical requirements. While the acid digestion method is more practical for routine use, the alkali fusion method offers higher accuracy for complex or refractory samples.

Cosmetics Raw Material

Cosmetics are a mixture of various raw materials processed by reasonable allocation. There are many kinds of cosmetics with different properties. According to the cosmetic raw material performance and use, can be divided into two categories of substrate raw materials and auxiliary raw materials. The former is a kind of main raw material of cosmetics, which occupies a large proportion in cosmetics formula and plays a major role in cosmetics. The latter play a role in shaping, stabilizing, or imbuing cosmetics with color, fragrance and other properties that are extremely important in small amounts in cosmetic formulations. Cosmetics is with natural, synthetic or extract all sorts of action different material as raw material, via heating, agitation and emulsification wait for production program processing and become chemical mixture material.

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