h) The degree of white
Principle:
Beam reflection measurement standard sample with MgO.
Equipment: Photometer.
Reagent: Standard MgO 99% pa
Ways of working:
(1) Insert the sample into the sample container similar to that used for container MgO;
(2) Measure the reflection index of the sample (A) and the reflection index of MgO (B);
(3) Each completed measurement 10 times the sample, the photometer must be calibrated with MgO to get a smaller deviation.
i) The degree of acid
Principle:
Dissolution of organic acids in a sample by using certain organic solvents (alcohol 95%) followed by penitaran with alkali (NaOH).
Equipment:
a) Balance analytical accuracy of 0.1 mg calibrated;
b) 250-ml Erlenmeyer; and
c) Buret 25 mL.
Reagent:
(1) Ethanol, C2H5OH 95% neutral;
(2) A solution of sodium hydroxide, NaOH, 0.05 M;
(3) phenolphthalein indicator, PP 1% in 60% alcohol.
Ways of working:
(1) Weigh carefully the 10 g sample (a), then insert it into the 250-ml Erlenmeyer;
(2) Add 100 mL ethanol 95% neutral and allow 24 hours while occasionally shaken then strained; and
(3) Titration of the filter with 50 mL of 0.05 M NaOH (c) in ethanol using PP indicator (b).
j) metal contaminants: Cadmium (Cd) and lead (Pb)
Principle:
Destruction example by dry ashing at a temperature of 450 ° C followed by dissolution in acid solution. Dissolved metal calculated using the tool Atomic Absorption Spectrophotometer (AAS) with a maximum wavelength of 228.8 nm to 283.3 nm for Cd and Pb.
Equipment:
(1) Atomic Absorption Spectrophotometer (AAS) along with the accessories (cathode lamps Cd and Pb) calibrated (preferably using graphite furnace AAS);
(2) The furnace is calibrated with a precision of 1 ° C;
(3) Balance analytical calibrated to the nearest 0.1 mg;
(4) electric heater;
(5) water bath;
(6) Pipette 0.05 mL measuring scale or micro burette calibrated;
(7) flask 1000 mL, 100 mL, and 50 mL, calibrated;
(8) Measuring cup capacity of 10 ml;
(9) The glass cup 250 mL;
(10) Bottle polypropylene;
(11) porcelain cup / platinum / quartz 50 mL to 100 mL; and
(12) Filter paper with specifications not berabu liquid particle retention of 20 to 25 lm.
Reagent:
(1) Nitric acid, HNO3;
(2) Hydrochloric acid, concentrated HCl;
(3) The solution of nitric acid, HNO3 0.1 N; 7 mL dilute HNO3 with distilled water in a 1000 mL volumetric flask and dilute to mark the line.
(4) A solution of hydrochloric acid, HCl 6 N; 500 mL of concentrated HCl diluted with distilled water in a 1000 mL volumetric flask and dilute to mark the line.
(5) standard solution 1000 mg / mL Cd; dissolve 1.000 g Cd with 7 ml of HNO3 in a 250-ml beaker and insert it into the measuring flask 1000 mL then dilute with distilled water to mark the line. Alternatively, it could be used Cd standard solution 1000 mg / mL ready to use.
(6) standard solution 200 mg / mL Cd; pipette 10 ml of standard solution of 1000 mg / mL Cd into 50 mL volumetric flask and then diluted with distilled water up to mark the line then shaken. The second standard solution has a concentration of 200 ug / mL Cd.
(7) the raw solution 20 mg / mL Cd; pipette 10 ml of standard solution of 200 ug / mL cadmium into 100 mL volumetric flask and then diluted with distilled water up to mark the line then shaken. The third standard solution has a concentration of 20 ug / mL Cd.
(8) working standard solution of Cd; pipette into a 100 mL volumetric flask respectively of 0 mL, 0.5 mL, 1 mL; 2 mL; 4 mL; 7 mL and 9 ml standard solution 20 mg / mL and then add 5 mL of HNO3 1 N or 6 N HCl, and dilute with distilled water to mark the line and shake. The working standard solution has a concentration of 0 mg / mL; 0.1 mg / mL; 0.2 mg / mL; 0.4 mg / mL; 0.8 mg / mL; 1.4 mg / mL and 1.8 mg / mL Cd.
(9) standard solution 1000 mg / mL Pb; dissolve 1,000 g Pb with 7 ml of HNO3 in a 250-ml beaker and insert it into the measuring flask 1000 mL then dilute with distilled water to mark the line. Alternatively, it could be used Pb standard solution of 1.000 mg / mL ready to use.
(10) the raw solution 50 mg / mL Pb; and pipette 5.0 ml of standard solution of 1.000 mg / mL Pb into a 100 mL volumetric flask and dilute with distilled water to mark the line and shake. The second standard solution has a Pb concentration of 50 ug / mL.
(11) working standard solution of Pb. pipette into a 100 mL volumetric flask respectively of 0 mL, 0.2 mL; 0.5 mL; 1 mL; 2 mL; 3 mL and 4 mL standard solution 50 mg / mL and then add 5 mL of HNO3 1 N or 6 N HCl, and dilute with distilled water to mark the line and shake. The working standard solution has a concentration of 0 mg / mL; 0.1 mg / mL; 0.25 mg / mL; 0.5 mg / mL; 1.0 mg / mL; 1.5 mg / mL and 2.0 mg / mL Pb.
Ways of working:
(1) Weigh 10 g to 20 g of sample accurately in a porcelain cup / platinum / quartz (m);
(2) Place the dish containing the test sample on top of electric heating and heat gradually until the test sample does not smoke anymore;
(3) Continue incineration in a furnace at a temperature of (450 ± 5) ° C until the ash is white, free from carbon;
(4) If the ashes are not free from carbon which is characterized by a grayish color, lightly mist with a few drops of water and add dropwise HNO3 Approximately 0.5 mL to 3 mL;
(5) Dry the cup above the electric heater and reinsert it into the furnace at a temperature of (450 ± 5) ° C and continue heating until white ash. Addition of HNO3 may be repeated if the ash is grayish;
(6) Dissolve white ash in 5 mL of 6 N HCl, while heated over an electric heater or a water bath until dry, then dilute with 0.1 N HNO3 and enter into a 50 mL measuring flask and then align to mark the lines with distilled water (V), if necessary, filter the solution using a filter paper into a polypropylene bottle;
(7) Prepare a blank solution by the addition of reagents and the same treatment as an example;
(8) Read the absorbance of the working standard solution and the sample solution against the blank using AAS at a wavelength maximum of about 228.8 nm to 283.3 nm for Cd and Pb;
(9) Create a calibration curve between metal concentrations (mg / mL) as the X-axis and absorbance as the Y axis;
(10) Plot the readings solution is an example of the calibration curve (C); and
(11) Calculate the metal content in the sample.
k) Metal Contamination: Tin (Sn)
Principle:
Examples didekstruksi with HNO3 and HCl then add KCl to reduce interference. Sn read using Atomic Absorption Spectrophotometer (AAS) at a wavelength of 235.5 nm with a maximum of N2O-C2H2 flame oxidation.
Equipment:
(1) Atomic Absorption Spectrophotometer (AAS) along with the accessories (cathode lamps Sn) calibrated;
(2) The furnace is calibrated with precision 1oC;
(3) Balance analytical calibrated to the nearest 0.1 mg;
(4) electric heater;
(5) water bath;
(6) flask 1000 ml, 100 ml and 50 ml, calibrated;
(7) Pipette 0.1 mL calibrated measuring scale;
(8) 250 ml Erlenmeyer flask;
(9) glass measuring 50 mL; and
(10) Glass cup of 250 mL.
Reagent:
(1) A solution of potassium chloride, 10 mg / mL K; dissolve 1.91 g of KCl with water to 100 mL.
(2) Nitric acid, HNO3;
(3) Hydrochloric acid, concentrated HCl;
(4) standard solution 1000 mg / mL Sn; and dissolve 1.000 g Sn with 200 mL of concentrated HCl in 1000 mL volumetric flask, add 200 ml of distilled water, cooled to room temperature and dilute with distilled water to mark the line.
(5) working standard solution of Sn.
Pipette 10 mL of concentrated HCl and 1.0 mL of KCl into each 100 mL volumetric flask. Add each 0 mL; 0.5 mL; 1.0 mL; 1.5 mL; 2.0 mL and 2.5 mL of standard solution of 1000 mg / mL Sn and dilute with distilled water to mark the line. The working standard solution has a concentration of 0 mg / mL; 5 mg / mL; 10 mg / mL; 15 mg / mL; 20 mg / mL and 25 mg / mL Sn.
Ways of working:
(1) Weigh sample of 10 g to 20 g (m) carefully into 250-ml Erlenmeyer flask, add 30 mL HNO3 and allow 15 minutes;
(2) Heat gently for 15 minutes in a fume hood, avoid the occurrence of excessive spark;
(3) Continue heating so that the remaining volume of 3 mL to 6 mL or until the sample was dry on the bottom, avoiding the formation of charcoal;
(4) Remove the Erlenmeyer of electric heating, add 25 ml of concentrated HCl, and heat up for 15 minutes until a burst of steam Cl 2 stops;
(5) Increase the heating and bring to a boil so that the residual volume of 10 mL to 15 mL;
(6) Add 40 ml of distilled water, stir, and pour into a 100 mL volumetric flask, rinse the Erlenmeyer flask with 10 mL of distilled water (V);
(7) Add 1.0 mL KCl, let cool at room temperature, align with distilled water up to mark the line and filter;
(8) Prepare the reference solution with the addition of reagents and the same treatment as an example;
(9) Read the absorbance of the working standard solution and the sample solution against the blank using AAS at a wavelength of 235.5 nm with a maximum of N2O-C2H2 flame oxidation;
(10) Create a calibration curve between metal concentrations (mg / mL) as the X-axis and absorbance as the Y axis;
(11) Plot the readings solution is an example of the calibration curve (C);
(12) Perform Duplo construction; and
(13) Calculate the Sn content in the sample.