{"id":3899,"date":"2025-09-04T10:56:14","date_gmt":"2025-09-04T02:56:14","guid":{"rendered":"https:\/\/www.pgeneral.com\/?p=3899"},"modified":"2025-09-04T10:56:14","modified_gmt":"2025-09-04T02:56:14","slug":"determination-of-lead-in-olive-oil-graphite-furnace-atomic-absorption-spectrometry","status":"publish","type":"post","link":"https:\/\/www.pgeneral.com\/id\/applications\/determination-of-lead-in-olive-oil-graphite-furnace-atomic-absorption-spectrometry\/","title":{"rendered":"Penentuan Timbal dalam Minyak Zaitun (Spektrometri Penyerapan Atom Tungku Grafit)"},"content":{"rendered":"

1. Method Overview<\/h2>\n
After the sample is digested by microwave, it is injected into the graphite furnace of an atomic absorption spectrophotometer. After electrothermal atomization, the sample absorbs the resonance line at 283.3 nm. Within a certain concentration range, the absorbance value is proportional to the lead 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>\nGraphite Furnace Atomic Absorption Spectrophotometer<\/td>\n1 set<\/td>\n–<\/td>\nLead Hollow Cathode Lamp<\/td>\n<\/tr>\n
2<\/td>\nArgon Gas<\/td>\n1 cylinder<\/td>\nPurity \u2265 99.99%<\/td>\n–<\/td>\n<\/tr>\n
3<\/td>\nCirculating Cooling Water System<\/td>\n1 set<\/td>\n–<\/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
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>\nEquipped with platinum resistor and infrared temperature measurement; pressure measurement accuracy: \u00b10.1\u2103<\/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>\nVolumetric Flask<\/td>\nSeveral<\/td>\nVolume: 100 mL<\/td>\n–<\/td>\n<\/tr>\n
6<\/td>\nTest Tube<\/td>\nSeveral<\/td>\nVolume: 10 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\n
Serial No.<\/th>\nName<\/th>\nTechnical Requirements<\/th>\nRemarks<\/th>\n<\/tr>\n<\/thead>\n
1<\/td>\nDiammonium Hydrogen Phosphate<\/td>\nAnalytical Reagent (AR)<\/td>\n–<\/td>\n<\/tr>\n
2<\/td>\nHydrochloric Acid<\/td>\nGuaranteed Reagent (GR)<\/td>\n–<\/td>\n<\/tr>\n
3<\/td>\nNitric Acid<\/td>\nMOS Grade<\/td>\n–<\/td>\n<\/tr>\n
4<\/td>\nPalladium Nitrate<\/td>\nAnalytical Reagent (AR)<\/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 (1+99)<\/td>\nMeasure 10 mL of nitric acid, slowly add it to 990 mL of water, and mix well.<\/td>\n–<\/td>\n<\/tr>\n
2<\/td>\nNitric Acid Solution (5+95)<\/td>\nMeasure 5 mL of nitric acid, slowly add it to 95 mL of water, and mix well.<\/td>\n–<\/td>\n<\/tr>\n
3<\/td>\nDiammonium Hydrogen Phosphate-Palladium Nitrate Solution<\/td>\nWeigh 0.02 g of palladium nitrate, dissolve it with a small amount of nitric acid solution (1+9), then add 2 g of ammonium dihydrogen phosphate. After dissolution, dilute to 100 mL with nitric acid solution (5+95) 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 08619<\/td>\nLead 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 0.2 g of the solid sample (precision to 0.001 g) into a microwave digestion vessel, add 5 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 approximately 1 mL. After the digestion vessel cools down, transfer the digested solution to a 25 mL volumetric flask with deionized water. Wash the digestion vessel with a small amount of water for 2~3 times, combine the washing solutions into the volumetric flask, and dilute to the marked volume with water. Mix well for later use; this is the sample test solution. Prepare a reagent blank test at the same time.<\/div>\n


<\/p>\n

Microwave Heating 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 Lead Standard Intermediate Solution: For the lead standard solution (1.0 \u03bcg\/mL), accurately pipette 0.1 mL of the lead standard stock solution (1000 \u03bcg\/mL) into a 100 mL volumetric flask, dilute to the marked volume with (1+99) nitric acid solution, and shake well.<\/div>\n<\/li>\n
  2. \n
    Preparation of Lead Standard Series: Accurately pipette 0.0, 0.1, 0.2, 0.3, and 0.4 mL of the lead standard solution (1.0 \u03bcg\/mL) into separate 10 mL volumetric flasks respectively. Dilute to the marked volume with (1+99) nitric acid solution to obtain the lead standard series solutions with concentrations of 0.0, 10.0, 20.0, 30.0, and 40.0 ng\/mL.<\/div>\n<\/li>\n<\/ol>\n

    3.2 Sample Testing<\/h3>\n
      \n
    1. Testing Conditions Reference testing conditions for the graphite furnace atomic absorption spectrophotometer: | Parameter | Specification (Lead) | | — | — | | Wavelength (nm) | 283.3 | | Spectral Bandwidth (nm) | 0.4 | | Element Lamp Current (mA) | 2 | | Background Correction Method | Deuterium Lamp |<\/li>\n<\/ol>\n


      <\/p>\n

      Graphite Furnace Heating Program<\/strong><\/div>\n


      <\/p>\n

      \n
      \n\n\n\n\n\n\n\n\n
      Step<\/th>\nProcedure<\/th>\nTemperature (\u2103)<\/th>\nHeating Time (s)<\/th>\nHolding Time (s)<\/th>\n<\/tr>\n<\/thead>\n
      1<\/td>\nDrying<\/td>\n120<\/td>\n10<\/td>\n10<\/td>\n<\/tr>\n
      2<\/td>\nAshing<\/td>\n650<\/td>\n10<\/td>\n15<\/td>\n<\/tr>\n
      3<\/td>\nAtomization<\/td>\n1900<\/td>\n0<\/td>\n2<\/td>\n<\/tr>\n
      4<\/td>\nCleaning<\/td>\n2000<\/td>\n1<\/td>\n2<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n


      <\/p>\n

        \n
      1. Sample Testing In ascending order of mass concentration, inject 10 \u03bcL of the lead standard series solution and 5 \u03bcL of the diammonium hydrogen phosphate-palladium nitrate solution into the graphite furnace simultaneously. After atomization, measure the absorbance values. Plot a standard curve with mass concentration as the abscissa and absorbance value as the ordinate. Read the data, input the sample weight, and check and record the results.<\/li>\n<\/ol>\n

        3.3 Result Calculation<\/h3>\n
        The lead content in the sample is calculated using the following formula:<\/div>\n<\/div>\n
        \"\"<\/div>\n

        <\/p>\n
        Where:<\/div>\n
          \n
        • X<\/span>\u00a0= Lead content in the sample, unit: milligram per kilogram (mg\/kg);<\/li>\n
        • C1<\/span>\u00a0= Mass concentration of lead in the sample test solution, unit: nanogram per milliliter (ng\/mL);<\/li>\n
        • C2<\/span>= Mass concentration of lead in the blank solution, unit: nanogram per milliliter (ng\/mL);<\/li>\n
        • V<\/span>\u00a0= Volume of the sample after constant volume, unit: milliliter (mL);<\/li>\n
        • m<\/span>\u00a0= Mass of the sample, unit: gram (g);<\/li>\n
        • 1000 = Conversion factor.<\/li>\n<\/ul>\n<\/div>\n