[Abstract]: This paper uses a microcomputer polar spectrometer to determine the sodium saccharin in food. The polarograph saccharin produces a second derivative wave at -1.68 volts in a neutral phosphoric acid solution at pH ,7, which is proportional to the wave height. The minimum detection concentration is 5mg/L, and the accuracy and precision meet the requirements of quantitative analysis. 1 Experimental part 1.1 Reagents and instruments Microcomputer polarographs, commonly used glass instruments. 1.1.1 Bottom solution: Weigh 13.6 g of anhydrous potassium dihydrogen phosphate, 14. lg of anhydrous sodium disodium, 10 g of sodium chloride, and add water to 1 L to prepare a neutral phosphoric acid solution of pH ≈7. 1.1.2 Sodium saccharin standard stock solution (A solution): fine [more details] Veterinary Drugs: refers to substances (including medicated feed additives) used to prevent, treat, diagnose animal diseases or purposefully regulate animal physiological functions.
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Trace element analysis, trace element detector, blood lead detector, micro, electrode, spectrometer, determination, food, medium, saccharin,
ã€Text content】:
In this paper, micro-computer polar spectrometer was used to determine sodium saccharin in food. The polarograph saccharin produces a second derivative wave at -1.68 volts in a neutral phosphoric acid solution at pH ,7, which is proportional to the wave height. The minimum detection concentration is 5mg/L, and the accuracy and precision meet the requirements of quantitative analysis.
1, the experimental part
1.1 Reagents and instruments Microcomputer polarographs, commonly used glass instruments.
1.1.1 Bottom solution: Weigh 13.6 g of anhydrous potassium dihydrogen phosphate, 14. lg of anhydrous sodium disodium, 10 g of sodium chloride, and add water to 1 L to prepare a neutral phosphoric acid solution of pH ≈7.
1.1.2 Sodium saccharin standard stock solution (A solution): Weigh accurately 0.8510g of sodium saccharin baked at 120 °C for 4h, and dilute to 1L. 1 ml of this solution contains 1.00 mg of sodium saccharin.
1.1.3 sodium saccharin standard solution (solution B): prepared before use. Pipette 10.0 ml of solution A to a volume of 100 ml. 1 ml of this solution contains 0.10 mg of sodium saccharin.
1.1.4 Phosphoric acid (10%): Dilute 10 ml of 85% phosphoric acid to 100 ml.
1.1.5 Hydrochloric acid (6mol/L), ***, 10% copper sulfate, 4% sodium hydroxide.
2, the experimental steps
2.1 Liquid sample: Pipette 5.00 ml of sample solution into a 25 ml absorption cell and add 1 drop of 6 mol/L hydrochloric acid. Accurately add 10.0ml *** and oscillate for about 10s. To be statically layered, accurately absorb 5.0ml of the upper layer in a 15ml beaker, place it on a water bath, volatilize it to dryness, and keep it for about 5 minutes, add 5.00ml of water and 5.00ml of liquid, use a small glass rod. Measured after stirring.
2.2 Solid and relatively viscous liquid: Accurately weigh 10.00 g of sample in a 50 ml absorption cell, add 30 ml of water, add 10 ml of 10% copper sulfate, 2.2 m 14% sodium hydroxide, and add water to 50 ml. Stir well and mix, stand for about 30 min and filter. Accurately pipet 5.0 ml of the filtrate into a 25 ml absorption cell and add 0.50 ml of 10% phosphoric acid. Accurately add 10.0ml *** and oscillate for about 10s. To be statically layered, accurately absorb 5.0 ml of the upper layer in a 15 ml beaker, place it on a water bath, volatilize to dryness, and keep it for about 10 minutes, add 5.00 ml of water and 5.00 ml of the bottom solution, using a small glass rod. After mixing, measure.
3, determination
3.1 Polarographic conditions: the working electrode is a mercury drop electrode, three-electrode system, initial potential -1.4 volts, termination potential -1.9 volts, 250 m / s speed scan, reference peak potential - 1.72 volts.
3.2 Making a standard curve: separately take the sodium saccharin standard solution (B solution) 0, 0.50, 1.00, 2.00, 3.00, 5.00 ml in a 10 ml absorption tank, add water to 5.00 ml each, then add 5.00 ml of the bottom solution, mix and mix Determined on a microcomputer polarograph.
4, calculation
Cx=A/M formula: Cx is the content of sample saccharin sodium, g/L (g/Kg); A is 10ml of sodium saccharin in the test solution, (mg); M is 10ml in the test solution Sample quality, g (ml).
5. Results and discussion
5.1 Sodium chloride in the bottom liquid can act as a stable peak current;
5.2 adding a little acid to the sample solution can improve the sensitivity;
5.3 When extracting, the water layer shall not be mixed into the layer of ***, and *** shall be completely evaporated;
5.4 Freshening clutter will occur when saccharin sodium is degraded;
5.5 The minimum detection concentration of this method is 5mg/L;
5.6 This method allows for difference: relative error <10%.
