{"id":3997,"date":"2025-10-10T16:54:03","date_gmt":"2025-10-10T08:54:03","guid":{"rendered":"https:\/\/www.pgeneral.com\/?p=3997"},"modified":"2025-10-10T16:54:03","modified_gmt":"2025-10-10T08:54:03","slug":"determination-of-calcium-in-milk-powder-flame-atomic-absorption-spectrometry","status":"publish","type":"post","link":"https:\/\/www.pgeneral.com\/id\/applications\/determination-of-calcium-in-milk-powder-flame-atomic-absorption-spectrometry\/","title":{"rendered":"Penentuan Kalsium dalam Bubuk Susu (Flame Atomic Absorption Spectrometry)"},"content":{"rendered":"

1. Method Overview<\/h2>\n
After the sample is digested, a lanthanum solution is added as a releasing agent. The sample is then atomized by a flame in an atomic absorption spectrometer, and the absorbance is measured at a wavelength of 422.7 nm. Within a certain concentration range, the absorbance is proportional to the calcium content. Quantitative determination 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>\nCalcium Hollow Cathode Lamp<\/td>\n<\/tr>\n
2<\/td>\nAir Compressor<\/td>\n1 set<\/td>\nRated discharge pressure: 0.3 MPa<\/td>\n–<\/td>\n<\/tr>\n
3<\/td>\nAcetylene Gas<\/td>\n1 cylinder<\/td>\nPurity \u2265 99.99%<\/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\n
Serial No.<\/th>\nName<\/th>\nQuantity<\/th>\nTechnical Requirements<\/th>\nAccessories<\/th>\n<\/tr>\n<\/thead>\n
1<\/td>\nElectronic Balance<\/td>\n1 set<\/td>\nSensitivity: 0.1 mg<\/td>\n–<\/td>\n<\/tr>\n
2<\/td>\nQuartz Crucible<\/td>\nSeveral<\/td>\nVolume: 100 mL<\/td>\n–<\/td>\n<\/tr>\n
3<\/td>\nAdjustable Electric Furnace<\/td>\n1 set<\/td>\nRated power: 2000 W<\/td>\n–<\/td>\n<\/tr>\n
4<\/td>\nMuffle Furnace<\/td>\n1 set<\/td>\nRated temperature: 1000 \u2103<\/td>\n–<\/td>\n<\/tr>\n
5<\/td>\nAdjustable Hot Plate<\/td>\n1 set<\/td>\nRated temperature range: Room temperature ~ 300 \u2103<\/td>\n–<\/td>\n<\/tr>\n
6<\/td>\nMicropipette<\/td>\n1 each<\/td>\nRanges: 100 \u03bcL ~ 1000 \u03bcL, 1000 \u03bcL ~ 5000 \u03bcL<\/td>\n–<\/td>\n<\/tr>\n
7<\/td>\nVolumetric Flask<\/td>\nSeveral<\/td>\nVolumes: 100 mL, 1000 mL<\/td>\n–<\/td>\n<\/tr>\n
8<\/td>\nColorimetric Tube<\/td>\nSeveral<\/td>\nVolume: 50 mL<\/td>\n–<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

2.2 Reagents<\/h3>\n

2.2.1 Raw Reagents<\/h4>\n
\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
3<\/td>\nLanthanum Oxide<\/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\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 and mix it with 950 mL of water uniformly.<\/td>\n–<\/td>\n<\/tr>\n
2<\/td>\nNitric Acid Solution (1+1)<\/td>\nMeasure 50 mL of nitric acid and mix it with 50 mL of water uniformly.<\/td>\n–<\/td>\n<\/tr>\n
3<\/td>\nHydrochloric Acid Solution (1+1)<\/td>\nMeasure 50 mL of hydrochloric acid and mix it with 50 mL of water uniformly.<\/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)080261<\/td>\nCalcium Single-Element Standard Substance Solution<\/td>\nConcentration: 1000 \u03bcg\/mL<\/td>\nProvided by National Institute of Metrology, China<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

3. Operational Procedures<\/h2>\n

3.1 Sample Preparation<\/h3>\n

3.1.1 Preparation of Test Solution<\/h4>\n
    \n
  1. \n
    Sample Pretreatment<\/p>\n
    <\/div>\n

    Accurately weigh 2 g of the sample (accurate to 0.0001 g) into a 100 mL quartz crucible. Place the crucible on an adjustable electric furnace, heat it gently to carbonize until no smoke is produced. Remove the crucible and transfer it to a muffle furnace, then ash at 550 \u2103 for 3~4 hours. Take out the crucible after cooling. If the sample is not completely ashed, add a few drops of nitric acid, place it on an adjustable hot plate, heat at 150 \u2103 to carefully evaporate to dryness, and then transfer it back to the muffle furnace at 550 \u2103 for further ashing for 1~2 hours until the sample turns into a white ash. Cool and take out the crucible, add 2 mL of nitric acid solution (1+1), place it on the adjustable hot plate, heat at 150 \u2103 to dissolve the sample. After cooling, dilute the solution to the marked volume in a 50 mL colorimetric tube with water. Conduct a reagent blank test simultaneously.<\/p><\/div>\n<\/li>\n

  2. \n
    Preparation of Sample Test Solution<\/p>\n
    <\/div>\n

    Pipette 1 mL of the digested solution into a 100 mL volumetric flask, add 5 mL of lanthanum solution (20 g\/L), dilute to the marked volume with nitric acid solution (5+95), and mix well. Prepare a reagent blank in the same way. Except for not adding the sample, the type and amount of reagents added to the blank test solution are the same as those of the test solution.<\/p><\/div>\n<\/li>\n<\/ol>\n

    3.1.2 Preparation of Standard Solutions<\/h4>\n
    Preparation of Calcium Standard Series<\/p>\n
    <\/div>\n

    Pipette 0 mL, 0.10 mL, 0.20 mL, 0.30 mL, and 0.40 mL of the calcium standard solution (1000 \u03bcg\/mL) into separate 100 mL volumetric flasks respectively. Add 5 mL of lanthanum solution (20 g\/L) to each flask, dilute to the marked volume with nitric acid solution (5+95), and mix well. The concentrations of this calcium standard series are 0 \u03bcg\/mL, 1.00 \u03bcg\/mL, 2.00 \u03bcg\/mL, 3.00 \u03bcg\/mL, and 4.00 \u03bcg\/mL.<\/p><\/div>\n

    3.2 Sample Testing<\/h3>\n

    1) Testing Conditions<\/h4>\n
    Reference Conditions for Flame Atomic Absorption Spectrophotometer<\/strong><\/div>\n
    <\/div>\n
    \n
    \n\n\n\n\n\n\n\n\n\n\n
    Parameter<\/th>\nSpecification<\/th>\n<\/tr>\n<\/thead>\n
    Wavelength<\/td>\n422.7 nm<\/td>\n<\/tr>\n
    Spectral Bandwidth<\/td>\n0.4 nm<\/td>\n<\/tr>\n
    Element Lamp Current<\/td>\n3.0 mA<\/td>\n<\/tr>\n
    Burner Height<\/td>\n10 mm<\/td>\n<\/tr>\n
    Fuel Flow Rate<\/td>\n1600 mL\/min<\/td>\n<\/tr>\n
    Air Compressor Pressure<\/td>\n0.22 MPa<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n

    2) Sample Testing<\/h4>\n
    Introduce the calcium standard series solutions into the flame atomizer in ascending order of concentration, and measure their absorbance. Plot a standard curve with the mass concentration of calcium in the standard series as the abscissa and the corresponding absorbance as the ordinate.<\/div>\n
    <\/div>\n
    Under the same experimental conditions as those for determining the standard solutions, introduce the blank solution and the sample test solution into the atomizer respectively, measure their corresponding absorbance, and perform quantitative determination by comparison with the standard series.<\/div>\n<\/div>\n