{"id":3891,"date":"2025-09-04T10:26:07","date_gmt":"2025-09-04T02:26:07","guid":{"rendered":"https:\/\/www.pgeneral.com\/?p=3891"},"modified":"2025-09-04T10:26:07","modified_gmt":"2025-09-04T02:26:07","slug":"determination-of-magnesium-in-sodium-bicarbonate-flame-atomic-absorption-spectrometry","status":"publish","type":"post","link":"https:\/\/www.pgeneral.com\/es\/applications\/determination-of-magnesium-in-sodium-bicarbonate-flame-atomic-absorption-spectrometry\/","title":{"rendered":"Determinaci\u00f3n del magnesio en bicarbonato de sodio (espectrometr\u00eda de absorci\u00f3n at\u00f3mica de llama)"},"content":{"rendered":"

1. Method Overview<\/h2>\n
After the sample is digested and atomized by flame, the absorbance is measured at a wavelength of 285.2 nm. Within a certain concentration range, the absorbance value of magnesium is proportional to its content, and quantification is performed by comparison with a standard series.<\/div>\n
\n

2. Instruments and Reagents<\/h2>\n

2.1 Instruments and Equipment<\/h3>\n

2.1.1 Testing Instruments<\/h4>\n
\n
\n\n\n\n\n\n\n\n
Serial No.<\/th>\nName<\/th>\nQuantity<\/th>\nTechnical Requirements<\/th>\nAccessories<\/th>\n<\/tr>\n<\/thead>\n
1<\/td>\nFlame Atomic Absorption Spectrophotometer<\/td>\n1 set<\/td>\n\/<\/td>\nMagnesium Hollow Cathode Lamp<\/td>\n<\/tr>\n
2<\/td>\nAcetylene Gas<\/td>\n1 cylinder<\/td>\nPurity \u2265 99.99%<\/td>\n\/<\/td>\n<\/tr>\n
3<\/td>\nAir Compressor<\/td>\n1 set<\/td>\nRated discharge pressure: 0.3 MPa<\/td>\n\/<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

2.1.2 Sample Pretreatment Equipment<\/h4>\n
\n
\n\n\n\n\n\n\n\n\n\n\n\n
Serial No.<\/th>\nName<\/th>\nQuantity<\/th>\nTechnical Requirements<\/th>\nAccessories<\/th>\n<\/tr>\n<\/thead>\n
1<\/td>\nMicrowave Digestion System<\/td>\n1 set<\/td>\n\/<\/td>\n\/<\/td>\n<\/tr>\n
2<\/td>\nTemperature-Controlled Hot Plate<\/td>\n1 set<\/td>\n\/<\/td>\n\/<\/td>\n<\/tr>\n
3<\/td>\nElectronic Balance<\/td>\n1 set<\/td>\nSensitivity: 0.1 mg<\/td>\n\/<\/td>\n<\/tr>\n
4<\/td>\nUltrapure Water System<\/td>\n1 set<\/td>\n\/<\/td>\n\/<\/td>\n<\/tr>\n
5<\/td>\nMicropipette<\/td>\n1 each<\/td>\nRanges: 20 \u03bcL~200 \u03bcL, 100 \u03bcL~1000 \u03bcL<\/td>\n\/<\/td>\n<\/tr>\n
6<\/td>\nVolumetric Flask<\/td>\nSeveral<\/td>\nVolume: 100 mL<\/td>\n\/<\/td>\n<\/tr>\n
7<\/td>\nColorimetric Tube<\/td>\nSeveral<\/td>\nVolume: 25 mL<\/td>\n\/<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

2.2 Reagents<\/h3>\n

2.2.1 Raw Reagents<\/h4>\n
\n
\n\n\n\n\n\n\n
Serial No.<\/th>\nName<\/th>\nTechnical Requirements<\/th>\nRemarks<\/th>\n<\/tr>\n<\/thead>\n
1<\/td>\nNitric Acid<\/td>\nMOS Grade<\/td>\n\/<\/td>\n<\/tr>\n
2<\/td>\nHydrochloric Acid<\/td>\nGuaranteed Reagent (GR)<\/td>\n\/<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

2.2.2 Prepared Reagents<\/h4>\n
\n
\n\n\n\n\n\n
Serial No.<\/th>\nName<\/th>\nPreparation Method<\/th>\nRemarks<\/th>\n<\/tr>\n<\/thead>\n
1<\/td>\nNitric Acid Solution (5+95)<\/td>\nMeasure 50 mL of nitric acid, slowly add it to 950 mL of deionized water, and mix well.<\/td>\n\/<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

2.3 Reference Standards<\/h3>\n

2.3.1 Stock Solution<\/h4>\n
\n
\n\n\n\n\n\n
Serial No.<\/th>\nNo.<\/th>\nName<\/th>\nTechnical Requirements<\/th>\nRemarks<\/th>\n<\/tr>\n<\/thead>\n
1<\/td>\nGBW(E)080126<\/td>\nMagnesium Single-Element Standard Solution<\/td>\nConcentration: 1000 \u03bcg\/mL<\/td>\nNational Institute of Metrology, China<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

3. Operation Procedure<\/h2>\n

3.1 Sample Preparation<\/h3>\n

3.1.1 Preparation of Test Solution<\/h4>\n
Accurately weigh 0.5 g of sodium bicarbonate sample (precision to 0.001 g) into a microwave digestion vessel, add 8 mL of nitric acid, and digest the sample according to the operating procedures of the microwave digestion system. After cooling, take out the digestion vessel, and evaporate the acid on a hot plate at 140\u2103~160\u2103 until the volume is reduced to 0.5 mL~1 mL. After the digestion vessel cools down, transfer the digested solution to a 25 mL colorimetric tube. Wash the digestion vessel with a small amount of water for 2~3 times, combine the washing solutions into the colorimetric tube, dilute to the marked volume with water, and mix well for later use. Prepare a reagent blank at the same time.<\/div>\n

 <\/p>\n

Microwave Digestion Program<\/strong><\/div>\n

 <\/p>\n

\n
\n\n\n\n\n\n\n\n\n\n
Step<\/th>\nTemperature\/\u2103<\/th>\nHolding Time\/min<\/th>\n<\/tr>\n<\/thead>\n
1<\/td>\n100<\/td>\n3<\/td>\n<\/tr>\n
2<\/td>\n120<\/td>\n3<\/td>\n<\/tr>\n
3<\/td>\n140<\/td>\n3<\/td>\n<\/tr>\n
4<\/td>\n160<\/td>\n3<\/td>\n<\/tr>\n
5<\/td>\n180<\/td>\n30<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

3.1.2 Preparation of Standard Solutions<\/h4>\n
    \n
  1. \n
    Preparation of Magnesium Standard Intermediate Solution (100 \u03bcg\/mL): Accurately pipette 10.0 mL of the magnesium standard stock solution (1000 \u03bcg\/mL) into a 100 mL volumetric flask, dilute to the marked volume with (5+95) nitric acid solution, and shake well.<\/div>\n<\/li>\n
  2. \n
    Preparation of Magnesium Standard Series: Accurately pipette 0.0, 0.1, 0.2, 0.3, and 0.4 mL of the magnesium standard intermediate solution (100 \u03bcg\/mL) into separate 100 mL volumetric flasks respectively. Dilute to the marked volume with (5+95) nitric acid solution and mix well. The concentrations of this standard series are 0.0, 0.1, 0.2, 0.3, and 0.4 \u03bcg\/mL.<\/div>\n<\/li>\n<\/ol>\n

    3.2 Sample Testing<\/h3>\n
      \n
    1. \n
      Testing Conditions Reference testing conditions for the flame atomic absorption spectrophotometer: | Parameter | Specification (Magnesium) | | — | — | | Wavelength (nm) | 285.2 | | Spectral Bandwidth (nm) | 0.2 | | Element Lamp Current (mA) | 3.0 | | Burner Height (mm) | 6 | | Fuel Gas Flow Rate (mL\/min) | 1500 | | Air Compressor Pressure (MPa) | 0.22 | | Background Correction Method | None |<\/div>\n<\/li>\n
    2. \n
      Sample Testing Adjust the instrument to its optimal working state, ignite the flame and adjust the fuel gas flow rate. Test the standard solutions and sample solutions in sequence, read the data, input the sample weight, and check and record the results.<\/div>\n<\/li>\n<\/ol>\n

      3.3 Result Calculation<\/h3>\n
      The magnesium content in the sample is calculated using the following formula:<\/div>\n<\/div>\n<\/div>\n<\/div>\n
      <\/div>\n
      \"\"<\/div>\n
      <\/div>\n
      \n
      \n
      \n
      Where:<\/div>\n
        \n
      • X<\/span>\u00a0= Magnesium content in the sample, unit: milligram per kilogram (mg\/kg);<\/li>\n
      • \u03c1<\/span>\u00a0= Mass concentration of magnesium in the sample test solution, unit: milligram per liter (mg\/L);<\/li>\n
      • \u03c10<\/span>\u00a0= Mass concentration of magnesium in the blank solution, unit: milligram per liter (mg\/L);<\/li>\n
      • f<\/span>\u00a0= Dilution factor of the digested sample solution;<\/li>\n
      • V<\/span>\u00a0= Total volume of the digested sample solution, unit: milliliter (mL);<\/li>\n
      • m<\/span>\u00a0= Mass of the sample, unit: gram (g).<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<\/div>\n