l) Contamination metals: mercury (Hg)
(1) n as high as 20 mm;
(2) Tube destruction;
(3) The destruction of 250 mL flask round basis;
(4) flask 1000 mL, 500 mL and 100 mL calibrated;
(5) glass measuring 25 mL;
(6) Pipette 0.05 mL measuring scale or micro burette calibrated; and
(7) The glass cup of 500 mL.
Reagent:
(1) A solution of sulfuric acid, H2SO4 9 M;
(2) solution of nitric acid, HNO3 7 M;
(3) A mixture HNO3: HClO4 (1: 1);
(4) Hydrogen peroxide, H2O2 concentrated;
(5) A solution of sodium molybdate, NaMoO4.7H2O 2%;
(6) reducing solution; Mix 50 mL of H2SO4 with 300 mL of distilled water in a 500-ml beaker and let cool to room temperature and then add 15 g NaCl, 15 g of hydroxylamine sulfate, and 25 g of SnCl2. Transfer to a 500 mL volumetric flask and dilute with distilled water to mark the line.
(7) A solution of sodium borohydride, NaBH4; 3 g powder dissolved NaBH4 and 3 g NaOH with distilled water in a 500 mL volumetric flask.
(8) A solution of diluent; enter 300 mL to 500 mL of distilled water into a 1000 mL volumetric flask and add 58 mL HNO3 and then add 67 mL H2SO4. Dilute with distilled water up to the mark and shake lines.
(9) standard solution 1000 mg / mL Hg; dissolve 0.1354 g HgCl2 with approximately 25 mL of distilled water in a 250-ml beaker and put into 100 mL volumetric flask and then diluted with distilled water up to the mark line.
(10) the raw solution 1 mg / mL Hg; pipette 1 ml of standard solution of 1000 mg / mL Hg into 1000 mL volumetric flask and dilute with diluent solution to mark the line and shake. The second standard solution has a concentration of 1 mg / mL.
(11) working standard solution of Hg; and pipette 0.25 mL respectively; 0.5 mL; 1 mL; and 2 ml of standard solution of 1 mg / mL into a separate 100 mL volumetric flask and dilute with diluent solution to mark the line. The working standard solution has a concentration of 0.002 5 mg / mL; 0.005 mg / mL; 0.01 mg / mL; 0.02 mg / mL Hg; and
(12) Stone boiling.
Ways of working:
(1) Wet ashing
(a) Weigh 5 g sample (m) carefully into destruction flask and add 25 mL H2SO4 9 M, 20 mL HNO3 7 M, 1 mL of 2% solution of sodium molybdate, and 5 grains up to 6 Boiling stones;
(b) Connect the destruction flask with cooling and heat over electric heating for 1 hour. Stop heating and leave for 15 minutes;
(c) Add 20 mL of a mixture of HNO3: HClO4 (1: 1) through refrigeration,
(d) Stop the water flow in the cooling and heat over high heat until white vapors arise. Continue heating for 10 minutes and cool;
(e) Add 10 ml of distilled water through the cooling carefully while pumpkin shake;
(f) Bring to a boil again for 10 minutes;
(g) Turn off electric heating and cooling wash with 15 mL of distilled water 3 times
(h) Then cool to room temperature;
(i) Move the destruction of the sample solution into 100 mL volumetric flask quantitatively and dilute with distilled water to mark the line (V);
(j) Pipette 25 mL of the above solution into a 100 mL volumetric flask and dilute with diluent solution to mark the line;
(k) Prepare a blank solution by the addition of reagents and the same treatment as an example;
(l) Add the solution to reducing the working standard solution Hg, the sample solution and the blank solution tool “HVG”;
(m) Read the absorbance of the working standard solution, the sample solution and reference solution uses no flame AAS at a wavelength of 253.7 nm;
(n) Create a calibration curve between metal concentrations (mg / mL) as the X-axis and absorbance as the Y axis;
(o) Plot the readings solution is an example of the calibration curve (C);
(p) Perform Duplo construction; and
(q) Calculate the Hg content in the sample.
(2) using a microwave digester destruction or the destruction of the closed system
(a) Weigh 1 g sample (m) to the destruction tube and add 5 ml HNO3, 1 mL of H2O2 and then close tightly;
(b) Put it in the microwave digester and working according to the user manual tools;
(c) Move the destruction of the sample solution into a 50 mL volumetric flask quantitatively and dilute with distilled water to mark the line (V);
(d) Prepare a blank solution by the addition of reagents and the same treatment as an example;
(e) Add the solution to reducing the working standard solution, the sample solution and reference solution at HVG tool;
(f) Read the absorbance of the working standard solution, the sample solution and reference solution uses no flame AAS at a wavelength of 253.7 nm;
(g) Create a calibration curve between metal concentrations (mg / mL) as the X-axis and absorbance as the Y axis;
(h) Plot the readings solution is an example of the calibration curve (C);
(i) Perform Duplo construction; and
(j) Calculate the Hg content in the sample.
m) contaminants arsenic (As)
Principle:
Examples didestruksi with acid into a solution of arsenic. AS5 + solution is reduced by KI into AS3 + and reacted with NaBH4 or SnCl2 forming AsH3 are then read by Atomic Absorption Spectrophotometer (AAS) at a wavelength of 193.7 nm maximum.
Equipment:
(1) Atomic Absorption Spectrophotometer (AAS) equipped with lights and a cathode As hydride vapor generator (HVG) calibrated;
(2) The furnace is calibrated with a precision of 1 ° C;
(3) Microwave digester;
(4) Balance analytical calibrated to the nearest 0.1 mg;
(5) electric heaters;
(6) or Bunsen Burner;
(7) Kjeldahl flask of 250 ml;
(8) A flask made of round 50 mL borosiklat unfounded.
(9) flask 1000 mL, 500 mL, 100 mL, and 50 mL, calibrated;
(10) glass measuring 25 mL;
(11) Pipette 25 mL volumetric calibrated;
(12) Pipette 0.05 mL measuring scale or micro burette calibrated;
(13) porcelain cup capacity of 50 ml; and
(14) Glass cup of 200 mL.
Reagent:
(1) Nitric acid, HNO3;
(2) sulfuric acid, concentrated H2SO4;
(3) perchloric acid, HClO4 concentrated;
(4) Ammonium oxalate, (NH4) 2C2O4 saturated;
(5) Hydrogen peroxide, H2O2 concentrated;
(6) A solution of sodium borohydride, NaBH4; 3 g NaBH4 dissolved and 3 g NaOH with distilled water up to the line mark in 500 mL volumetric flask.
(7) A solution of hydrochloric acid, HCl 8 M; Dilute 66 mL of concentrated HCl into 100 mL volumetric flask with distilled water up to the mark line.
(8) A solution of tin (II) chloride, SnCl2.2H2O 10%; Weigh 50 g SnCl2.2H2O into a 200 ml beaker and add 100 ml of concentrated HCl. Heat until a clear solution and let cool then pour into a 500 mL volumetric flask and dilute with distilled water to mark the line.
(9) A solution of potassium iodide, KI 20%; Weigh 20 g KI in 100 mL volumetric flask and dilute with distilled water to mark the line (the solution should be prepared immediately before use).
(10) A solution of Mg (NO3) 275 mg / mL; dissolve 3.75 g of MgO with 30 mL H2O carefully, add 10 ml of HNO3, cool and dilute to 50 ml with distilled water;
(11) standard solution 1000 mg / mL As; dissolve 3 g As2O3 1,320 dry with little NaOH 20% and neutralize with HCl or HNO3 1: 1 (1 part acid: 1 part water). Enter into a 1 L volumetric flask and dilute with distilled water to mark the line.
(12) standard solution 100 mg / mL As; pipette 10 ml of standard solution As 1000 ug / mL in 100 mL volumetric flask and dilute with distilled water to mark the line. The second standard solution has a concentration of 100 ug / mL As.
(13) the raw solution 1 mg / mL As; and pipette 1 mL of arsenic standard of 100 mg / L in a 100 mL volumetric flask and dilute with distilled water to mark the line. The third standard solution has a concentration of 1 mg / mL As.
(14) As working standard solution; pipette 1.0 mL respectively; 2.0 mL; 3.0 mL; 4.0 mL and 5.0 mL of standard solution of 1 mg / mL As to the separate 100 mL volumetric flask and dilute with distilled water to mark the line and shake the working standard solution has a concentration of 0.01 mg / mL; 0.02 mg / mL; 0.03 mg / mL; 0.04 g / mLdan 0.05 ug / mL As.
Ways of working:
(1) Wet ashing
(a) Weigh 5 g to 10 g sample (m) into a 250-ml Kjeldahl flask, add 5 ml to 10 ml of concentrated HNO 3 and 4 mL to 8 mL of concentrated H2SO4 with caution;
(b) After the reaction is finished, reheat and add HNO3 little by little so that the sample is brown or blackish;
(c) Add 2 mL HClO4 70% piecemeal and heat again so the solution becomes clear or yellow (in case authoring after addition of HClO4, HNO3 add another bit);
(d) Cool, add 15 mL H2O and 5 mL (NH4) 2C2O4 saturated;
(e) Heat causing steam SO3 neck flask;
(f) Cool, transfer quantitatively into a 50 mL volumetric flask and dilute with distilled water to mark the line (V);
(g) Pipette 25 mL of the above and add 2 ml of HCl 8 M, 0.1 mL of KI 20% then shake and allow at least 2 minutes;
(h) Prepare a blank solution by the addition of reagents and the same treatment as an example;
(i) Add a solution of reducing agent (NaBH4) into the working standard solution As, the sample solution and reference solution at HVG tool;
(j) Read the absorbance of the working standard solution, the sample solution and reference solution uses no flame AAS at a wavelength of 193.7 nm;
(k) Create a calibration curve between metal concentrations (mg / mL) as the X-axis and absorbance as the Y axis;
(l) Plot the readings solution is an example of the calibration curve (C);
(m) Perform Duplo construction; and
(n) Calculate the content of As in the example.
(2) using a microwave digester destruction or the destruction of the closed system
(a) Weigh 1 g sample (m) to the destruction tube and add 5 ml HNO3, 1 mL of H2O2 and then close tightly;
(b) put in the microwave digester and working according to the user manual tools;
(c) after cooling, transfer the solution into the destruction of 25 mL volumetric flask quantitatively and dilute with distilled water to mark the line (V);
(d) pipette 10 mL of destruction into the flask of borosilicate based round of 50 mL, add 1 mL solution of Mg (NO3) 2, uapkan above the electric heater to dry and arangkan. Abukan in a furnace at a temperature of 450 ° C (± 1 hour);
(e) cooled, diluted with 2.0 mL of 8 M HCl, 0.1 mL of KI 20% and leave at least 2 minutes. Pour the solution into the sample tube on the tool;
(f) prepare NaBH4 and HCl in place as determined by the tool;
(g) As working standard solution pour 0.01 mg / mL; 0.02 mg / mL; 0.03 mg / mL; 0.04 mg / mL; 0.05 mg / mL and blanks into the sample tube 6 others. Turn on or Bunsen burner and a key regulator of the flow of reagents and sample flow;
(h) read the absorbance value of the highest standard solution and a sample of work As with blanks as a correction;
(i) create a calibration curve between As concentrations (mg / mL) as the X-axis and absorbance as the Y axis;
(j) plot the results of reading the sample solution for calibration curve (C);
(k) to do the work Duplo; and
(l) calculate the content of As in the example.