On May 13, national market supervisory management board releases chromium of the lead in tea to determine greenly law of the proved recipe that reach check, it is announcement full text below.
The market superintends total bureau about releasing " the art in tea is green (plumbic chromium is green) determine " the announcement of law of proved recipe of food complement check
(2019 the 21st)
According to " job of law of additional check proved recipe provides food " concerned requirement, " the art in tea is green (plumbic chromium is green) determine " law of proved recipe of food complement check already approval of total bureau of national market supervisory government, grant to release now.
Hereby announcement.
Accessory: The art in tea is green (plumbic chromium is green) determine.doc
The art in tea is green (plumbic chromium is green) determine
BJS 201910
1 limits
This standard provided content of acerbity lead of the chromium in tea the first piece determine method.
This standard applies to acerbity lead of the chromium in tea the first piece determine.
This standard provided the qualitative means with the green art in tea the 2nd piece.
This standard applies to the art in tea the 2nd piece green qualitative decide.
2 term and definition
Following term and definition apply to this standard.
2.1 art are green
Art is green renown lead chromium is green, with dye of chromic acerbity lead precipitation arrives Tiela is painty and dispersive body go up or use dye of chromic acerbity lead and Tiela dye to mix all can a kind of dye that preparation gives. The bases with green art is chromic acerbity lead and Tie La, and the scale of chromic acerbity lead not under 50% .
Of the first chromic acerbity lead determine
Of plumbic content determine use method of active and effective national level GB 5009.12, of CrO42- determine choose undermentioned method.
The first way is efficient fluid photograph color atlas - usage of couplet of mass spectra of inductance coupling plasma (HPLC-ICP/MS)
3 principles
After incinerate of tea sample classics, after among them CrO42- is extracted via alkalescent extraction fluid, undertake depart with fluid photograph color atlas, the target compound after depart is sent into ICP fire blaze by carrier gas through pulverization, via evaporating, solution leaves, the process such as atomization, ionization, major translate into takes positive electrical charge ionic, classics ion collects a system to enter mass spectrograph, mass spectrograph undertakes departing determining according to pledging carry on one's shoulder is compared. Compare in order to withhold time and qualitative carry on one's shoulder qualitative, ration of external standard method.
4 reagent and material
Unless have a specification additionally, this methodological place all is super grade with reagent pure, water is the one class water that GB/T 6682 provides.
4.1 reagent
4.1.1 nitric acid (HNO3) .
4.1.2 ammonia water (NH3 · H2O) .
4.1.3 oxyhydrogen change sodium (NaOH) : The analysis is simple.
4.1.4 anhydrous sodium carbonate (Na2CO3) .
4.2 reagent are made up
Fluid of 4.2.1 alkalescent extraction (0.1 Mol/L NaOH and 0.056 Mol/L Na2CO3) : Say to take 0.05 GNaOH of 4.0 ± (4.1.3) with 6 ± 0.05g Na2CO3 (4.1.4) dissolve and allow surely to 1 L, leave solution in 20-25 ℃ sealed in saving bottle of Yu Juyi Xi, the PH when using must achieve 11.5 above, period of efficacy a month.
Fluid of 4.2.2 alkalescent extraction (0.2 Mol/L NaOH and 0.112 Mol/L Na2CO3) : Say to take 0.05 GNaOH of 8.0 ± (4.1.3) with 12 ± 0.05gNa2CO3 (4.1.4) dissolve and allow surely to 1 L, leave solution in 20-25 ℃ sealed in saving bottle of Yu Juyi Xi, the PH when using must achieve 11.5 above, period of efficacy a month.
Solution of 4.2.3 nitric acid (5 Mol/L) : Take 357 ML nitric acid (4.1.1) use Shui Dingrong to 1000 ML, mix even stand-by. Solution avoids below 20-25 ℃ light is saved, if solution shows yellow,need to be made up afresh.
Solution of 4.2.4 nitric acid (1+9) : Take 10 ML nitric acid (4.1.1) mix with 90 ML water, shake up.
4.2.5 hartshorn (1+9) : ? ?0 ML ammonia water (4.1.2) mix with 90 ML water, shake up.
Solution of 4.2.6 ammonium nitrate (0.05 Mmol/L) : 3.4 ML nitric acid is added in measuring water certainly (4.1.1) with 3.7mL ammonia water (4.1.2) , use Shui Dingrong to 1 L, shake up; With nitric acid solution (4.2.4) or hartshorn (4.2.5) adjustment PH is inside 7.0-7.2 limits.
4.3 standard items
Chromic acerbity lead: Lead Chromate, CAS date: 7758-97-6, structural formula PbCrO4, the element is measured 323.18, purity ≥ 99% .
Of 4.4 standards solution make up
4.4.1CrO42- standard lays in fluid: Accurate say to take acerbity lead of 0.0279 G chromium reference materials, in 100 ML beaker, add juice of 50 ML alkalescent extraction (4.2.2) in boiler of bath of water of agitate of magnetic force of park constant temperature, in 90 ℃ - temperature of 95 ℃ issues uninterrupted agitate 30 Min, the refrigeration after be being taken out comes to the move after room temperature in bottle of 100 ML capacity, rinse beaker with water and move is measured to the look in bottle, use Shui Dingrong to scale. The chroma of the CrO42- in solution is 100 Mg/L. Or use solution of 6 price chromic level to undertake making up.
4.4.2Fluid of CrO42- standard job:
Take 1.0 MLCrO42- standard to lay in fluid (4.4.1) with ammonium nitrate solution (4.2.6) calm look comes 10 ML, make among the standard fluid, chroma is 10 Mg/L.
Absorb respectively 0.05, 0.1, 0.2, 0.5, 1, 2, fluid allows measuring flask at 100 ML among 5.0 ML standard in, with ammonium nitrate solution (4.2.6) be allowed surely and mix even, cross film of filter of water system small hole (M of 0.45 μ ) , stay machine determine. The chroma of CrO42- of fluid of this standard job is G/L of 5 μ respectively, g/L of 10 μ , g/L of 20 μ , g/L of 50 μ , g/L of 100 μ , g/L of 200 μ , g/L of 500 μ . Working fluid uses this standard to match now now.
5 instruments and equipment
Note: Glass service and crucible all need with nitric acid solution (1+4) immerse 2 H, rinse repeatedly with water, use ionic water to be rinsed clean finally.
Color atlas of photograph of 5.1 concentrated juice - couplet of mass spectra of inductance coupling plasma uses instrument (HPLC-ICP/MS) .
5.2 analysises balance: Feeling quantity is 0.1 Mg and 0.01 G.
5.3 adjustable type resistor furnace, power is 2000 W.
Boiler of bath of water of constant temperature of agitate of 5.4 magnetic force: Can be in 90 ℃ - constant temperature of 95 ℃ .
5.5 PH plan: Precision is 0.01.
5.6 sample smash device.
6 sample preparation and save
Tea sample goes miscellaneous hind, put into disintegrator to smash, sample crosses standard net to sift entirely (M of 425 μ ) , in Chu Yujie clean container, as to shady and cool and dry place sealed save, reserve.
7 analysises measure
7.1 sample are extracted
Accurate say to take smash even tea sample 1 G(arrives accurately 0.01 G) in 100 ML crucible, get on crucible park electric stove with most high-power calcination comes without Bai Yan. Refrigeration adds juice of 50 ML alkalescent extraction to room temperature hind (4.2.1) , in boiler of bath of water of constant temperature of agitate of park magnetic force, in 90 ℃ - temperature of 95 ℃ issues uninterrupted agitate 30 Min, the refrigeration after be being taken out comes room temperature, in deciding a look to allow measuring flask to 100mL, take 1.0 ML to use ammonium nitrate solution from which (4.2.6) calm look comes 50 ML (or according to actual chroma proper dilute) , cross film of filter of water system small hole (M of 0.45 μ ) , stay machine determine. Make blank test by same operation method.
7.2 instruments reference condition
Reference condition of color atlas of 7.2.1 fluid photograph
Chromatographic column: G3268-80001 chromatographic column, (Column grows 30 Mm, internal diameter 4.6 Mm) , or equivalent column.
Photograph of going from place to place: The ammonium nitrate solution of 0.05 Mmol/L (4.2.6) .
: of wash out means? Does discuss admit grant anthology?
Velocity of flow: 0.6 ML/min.
Take kind amount: L of 50 μ .
Reference condition of mass spectrograph of plasma of 7.2.2 inductance coupling
Mode: Mode of collision reaction pool; RF incident power is 1600 W; Carrier gas is high pure argon is angry; Carrier gas velocity of flow is 1.0 L/min; Atomizer: Xuan sheds atomizer; Collision reaction is enraged (He) , velocity of flow is 3.5mL/min; Detect quality counts M/z=52(Cr) .
7.3 ration determine
Of 7.3.1 standards curve make
Absorb solution of series of standard (4.4.2) color atlas of photograph of fluid of infuse of L of 50 μ - mass spectrograph of inductance coupling plasma, by instrument reference condition (7.2) undertake determining, get corresponding chromatogram, in order to retain time qualitative. It is the abscissa with the chroma of compound of the target in solution of series of standard, it is ordinate with chromatographic peak area, scale standard curve.
Of 7.3.2 sample solution determine
Below same condition, absorb blank solution, sample solution (7.1) color atlas of photograph of fluid of infuse of L of 50 μ - couplet of mass spectra of inductance coupling plasma undertakes determining with appearance, get corresponding chromatogram (refer to appendix A) , in order to retain time qualitative. Get waiting for measuring the content of the constituent in fluid according to standard curve, parallel determines frequency not less than two.
8 analysises are stated as a result
Acerbity root of the chromium in 8.1 sample (CrO42- ) content presses type (1) computation:
... ... ... ... (1)
In type:
X -- the content of the CrO42- in sample, the unit is milligram every kilogram (Mg/kg) ;
C1 -- the chroma of the CrO42- in sample solution, the unit is microgramme every litres (μ G/L) ;
C0 -- the chroma of the CrO42- in solvent blank, the unit is microgramme every litres (μ G/L) ;
V -- sample solution holds bulk surely, the unit is milliliter (ML) ;
? -- ; of multiple of sample solution dilute
1000 -- reduction coefficient;
M -- sample quality, the unit is a gram (G) .
The computation of content of chromic acerbity lead in 8.2 sample:
When ≥ of content of CrO42- content Pb 0.5597 when, the Pb content that sample measures is multiplied with reduction coefficient 1.56, get chromic acerbity lead namely (with PbCrO4 plan) content; When CrO42- content / Pb content ＜ 0.5597 when, the CrO42- content that sample measures is multiplied with reduction coefficient 2.787, get chromic acerbity lead namely (with PbCrO4 plan) content.
Computation retains 3 significant numbers as a result.
9 detect methodological precision, sensitivity, accuracy
9.1 precision
In repeat two independence that gain below the condition to determine 10% what the absolutely difference value of the result must not exceed arithmetical average.
9.2 sensitivity
It is 1.0 G when quantity weighing appearance, the dilute after the bulk that decide a look is 100 ML 50 times when determining, pbCrO4 check goes out be restricted to be 10 Mg/kg, ration is restricted 30 Mg/kg.
9.3 accuracy
This methodological CrO42- adds chroma to be inside 30~300 Mg/kg limits, reclaim rate for 87.1%~105.9% .
Law of color atlas of ion of the 2nd law (IC law)
10 principles
After calcination of tea sample classics, among them CrO42- is extracted via alkalescent extraction fluid, fall in basic requirement (PH=9.0 ± 0.5) , use anion to exchange chromatographic column depart, ionic color atlas - conductance detector determines, ration of external standard method.
11 reagent and material
Unless have a specification additionally, this methodological place all is super grade with reagent pure, water is the one class water that GB/T 6682 provides.
11.1 reagent
11.1.1 thick vitriolic (H2SO4) .
11.1.2 nitric acid (HNO3) .
11.1.3 bicarbonate natrium (NaHCO3) .
Do 11.1.4 oxyhydrogen change sodium (NaOH) : ? Treat Ju handsome?
11.1.5 anhydrous sodium carbonate (Na2CO3) .
11.2 reagent are made up
Fluid of 11.2.1 alkalescent extraction: Make up with 4.2.1.
Solution of 11.2.2 nitric acid (5 Mol/L) : Make up with 4.2.3.
Fluid of 11.2.3 drip washing lays in fluid (40 Mmol/L sodium carbonate and 10 Mmol/L bicarbonate natrium mix solution) : Say to take sodium carbonate of 4.25 G anhydrous respectively (11.1.5) with 0.84 G bicarbonate natrium (11.1.3) , dissolve with water and allow surely to 1 L, mix even stand-by.
Fluid of 11.2.4 drip washing uses liquid (4 Mmol/L sodium carbonate and 1 Mmol/L bicarbonate natrium mix solution) : Lay in drip washing fluid fluid (11.2.3) uses water dilute 10 times, mix even, film of filter of small hole of classics water system (M of 0.45 μ ) after smoking filter, use.
Fluid of 11.2.5 second birth: Absorb 2 ML thick vitriolic (11.1.1) use Shui Dingrong to 1L, shake up, film of filter of small hole of classics water system (M of 0.45 μ ) after smoking filter, use.
11.3 standard items
With 4.3.
Of 11.4 standards solution make up
Root of 11.4.1 chromic acid (CrO42- ) the standard lays in fluid: Make up with 4.4.1.
11.4.2Fluid of CrO42- standard job:
The CrO42- level that takes chroma to be 100 Mg/L lays in fluid (4.4.1) 10 ML uses Shui Dingrong to 100 ML, make among the standard fluid, chroma is 10 Mg/L.
Absorb respectively 0.2, 0.5, 1, 5, 10, fluid allows measuring flask at 100 ML among 20.0 ML standard in, mix even with Shui Dingrong, cross film of filter of water system small hole, stay machine determine. The chroma of CrO42- of solution of this standard job is G/mL of 0.02 μ respectively, g/mL of 0.05 μ , g/mL of 0.10 μ , g/mL of 0.50 μ , g/mL of 1.00 μ , g/mL of 2.00 μ . Working fluid uses this standard to match now now.
12 instruments and equipment
Appearance of 12.1 ionic color atlas, match conductance detector, system of carbonate drip washing. If use hydroxyl system, the condition sees appendix C.
12.2 analysises balance: Feeling quantity 0.1mg and 0.01 G.
12.3 adjustable type resistor furnace, power is 2000W.
Boiler of bath of water of constant temperature of agitate of 12.4 magnetic force: Can be in 90 ℃ - constant temperature of 95 ℃ .
12.5 PH plan: ? holds the post of?.01.
12.6 sample smash device.
13 sample preparation and save
With 6.
14 analysises measure
14.1 sample are extracted
Accurate say to take smash even tea sample 1 G(arrives accurately 0.01 G) in 100 ML crucible, get on crucible park electric stove with most high-power calcination comes without Bai Yan. Refrigeration adds juice of 50 ML alkalescent extraction to room temperature hind (4.2.1) , in boiler of bath of water of agitate of magnetic force of park constant temperature, in 90 ℃ - temperature of 95 ℃ issues uninterrupted agitate 30 Min, the refrigeration after be being taken out comes room temperature, move comes in 100mL beaker, with nitric acid solution (4.2.3) moves PH to 9 ± 0.5 hind move comes in bottle of 500 ML capacity, mix even with Shui Dingrong. Cross film of filter of water system small hole (M) of 0.45 μ , stay machine determine. Make blank test by same operation method.
Condition of 14.2 ionic color atlas
Chromatographic column: MetrosepA Supp 5-150 or the anion chromatographic column that comparative.
Detector: Conductance detector.
Restrain implement: MSM ∥ chemistry is restrained implement.
Column is lukewarm: 30 ℃ .
Velocity of flow: 0.7mL/min.
Take kind amount: 20 μ L.
14.3 ration determine
Of 14.3.1 standards curve make
Absorb solution of series of standard (11.4.2) appearance of color atlas of ion of infuse of L of 20 μ , by instrument reference condition (14.2) undertake determining, get corresponding chromatogram, in order to retain time qualitative. It is the abscissa with the chroma of compound of the target in solution of series of standard, it is ordinate with the peak area of chromatographic peak, scale standard curve.
14.3.2 sample determine
Below same condition, absorb blank solution, sample solution respectively (14.1) L of 20 μ , by instrument reference condition (14.2) undertake determining, get corresponding chromatogram (refer to appendix B) , in order to retain time qualitative. Get waiting for measuring the concentration of the constituent in fluid according to standard curve, parallel determines frequency not less than two.
15 results are calculated
Acerbity root of the chromium in 15.1 sample (CrO42- ) content presses type (2) computation:
... ... ... (2)
In type:
X -- the content of the CrO42- in sample, the unit is milligram every kilogram (Mg/kg) ;
C1 -- the chroma of the CrO42- in sample solution, the unit is microgramme every milliliter (μ G/mL) ;
C0 -- the chroma of the CrO42- in sample blank fluid, the unit is microgramme every milliliter (μ G/mL) ;
V -- sample solution holds bulk surely, the unit is milliliter (ML) ;
1000 -- reduction coefficient;
M -- sample quality, the unit is a gram (G) .
The computation of content of chromic acerbity lead in 15.2 sample:
With 8.2.
Computation retains 3 significant numbers as a result.
The precision of 16 methods, sensitivity, accuracy
16.1 precision
In repeat two independence that gain below the condition to determine 10% what the absolutely difference value of the result must not exceed arithmetical average.
16.2 sensitivity
It is 1.0 G when quantity weighing appearance, when the bulk that decide a look is 500 ML, pbCrO4 check goes out be restricted to be 10 Mg/kg, ration is restricted 30mg/kg.
16.3 accuracy
This methodological CrO42- adds chroma to be inside 30~300 Mg/kg limits, reclaim rate for 85.17~107.59% .
The 2nd Tie La decides sexual test and verify
17 principles
Root of bases ferrous cyanogen issues distillation to decompose a prussiate in acidity condition, with reaction of chloric amine T, generate chloridize cyanogen, generate blue dye with color developing agent, prismatic photometry determines.
18 reagent and material
Unless have a specification additionally, this methodological place all is an analysis with reagent pure, water is the 3 class water that GB/T 6682 provides.
18.1 reagent
18.1.1 oxyhydrogen change sodium (NaOH) .
Hydrogen of 18.1.2 anhydrous phosphoric acid 2 natrium (Na2HPO4) .
18.1.3 anhydrous phosphoric acid 2 hydrogen Potassium (KH2PO4) .
T of 18.1.4 chloric amine (C7H7ClNNaO2S · 3H2O) .
18.1.5 tartaric acid (C4H6O6) .
18.1.6 phenolphthalein (C20H14O4) .
18.1.7 1- phenyl - 3- is methylic - ketone of Lin of 5- Bi Zun (C10H10N2O) .
18.1.8 ice second is acerbity (CH3COOH) .
18.1.9 anhydrous alcohol (CH3CH2OH) .
18.1.10 pyridine (C5H5N) .
18.1.11 methylic orange (C14H14N3SO3Na) .
18.2 reagent are made up
18.2.1NaOH solution (0.1 Mol/L) : Accurate say to take 1.0 G NaOH(18.1.1) , use Shui Dingrong to 250 ML, shake up is stand-by.
18.2.2NaOH solution (0.5 Mol/L) : Accurate say to take 5.0 G NaOH(18.1.1) , use Shui Dingrong to 250 ML, shake up is stand-by.
Solution of 18.2.3 phosphate amortize (PH=7.0) : Accurate say to take hydrogen of 42.6 G anhydrous phosphoric acid 2 natrium (18.1.2) and 13.6 G anhydrous phosphoric acid 2 hydrogen Potassium (18.1.3) , add Shui Rong to solve, calm look comes 1L, shake up is stand-by.
Solution of T of 18.2.4 chloric amine (10 G/ L) : Accurate say to take T(18.1.4) of 1.0 G chloric amine, use Shui Dingrong to 100 ML, shake up is stand-by, use now match now.
18.2.5 phenolphthalein indicate fluid: Accurate say to take 1.0g phenolphthalein (18.1.6) at 60 ML anhydrous alcohol (in 18.1.9) , add water 40mL, shake up is stand-by.
18.2.6 pyridine - solution of ketone of Bi Zun Lin (5 G/L) : Accurate say to take phenyl of 1.0 G 1- - 3- is methylic - ketone of Lin of 5- Bi Zun (18.1.7) , dissolve at 200 ML anhydrous alcohol (in 18.1.9) , add 1.2 ML pyridine (18.1.10) , mix even stand-by, use now match now.
18.2.7 second acerbity solution (0.1mol/ L) : Accurate absorb 1.15 ML to put second acid on the ice (18.1.8) , use Shui Dingrong to 200 ML, shake up is stand-by.
Indicator of 18.2.8 methylic orange (0.5 G/L) : Accurate say to take 50 Mg methylic orange (18.1.11) , in dissolve Yushui, calm look comes 100 ML, shake up is stand-by.
18.3 standard items
Tie La: PrussionBlue, CAS date: 14038-43-8, structural formula Fe4[Fe(CN)6]3, the element is measured 859.23, purity ≥ 99% .
18.4 ginseng are made up than solution
Accurate say to take reference materials of 0.0150 G Tie La at 250 ML tall model in beaker, accurate add solution of 100 ML NaOH (18.2.1) , after 30 Min of the concussion below room temperature, take 10.0 ML to be allowed surely to 100 ML, take diluent 1.0 ML in flask of 500 ML distill, add water to liquid gross to be 150mL about, join 1~2 to drip methylic orange indicator (18.2.8) , tartaric acid of rejoin 2 G (18.1.5) , solution turns into by orange yellow orange is gules, device of rapid join good distill, condensation tubal lower end is inserted fill have solution of 10 ML NaOH (18.2.2) in bottle of 100 ML capacity, collect distillation fluid, adjust temperature is in distillation speed control 2 ML/min~3mL/min, when distillation fluid is close to 100 ML, stop to heat, get off capacity bottle, use Shui Dingrong to scale, shake up. The chroma of the Tie La in this standard solution is 0.15 Mg/L.
19 instruments and equipment
19.1 spectrophotometer: Distribute poll of 1 Cm colorimetric.
19.2 analysises balance: Feeling quantity 0.01 Mg and 0.01 G.
Device of distill of 19.3 500 ML: Match condenser and polyethylene capillary.
19.4 oscillators.
19.5 centrifugal.
20 analysises measure
20.1 sample preparation
Accurate say to take come accurately without the tea sample 10g(that smash 0.01 G) , accurate add solution of 100 ML NaOH (18.2.1) at 250 ML tall model in beaker, after 30 Min of the concussion below room temperature, go with funnel filter tea, filtrate at 3000 R/min centrifugal 5 Min, accurate move take clear liquid 50 ML in flask of 500 ML distill, add water to liquid gross to be 150 ML about, join 1~2 to drip methylic orange indicator (18.2.8) , tartaric acid of rejoin 2 G (18.1.5) , solution turns into by orange yellow orange is gules, device of rapid join good distill, condensation tubal lower end is inserted fill have solution of 10 ML NaOH (18.2.2) in bottle of 100 ML capacity, collect distillation fluid, adjust temperature is in distillation speed control 2 ML/min~3 ML/min, when distillation fluid is close to 100 ML, stop to heat, get off capacity bottle, use Shui Dingrong to scale, shake up, wait for measure. Make blank test at the same time, blank solution is divided do not add lye (18.2.1) with tartaric acid (18.1.5) outside, all press (20.1) operation.
20.2 determine
Accurate move take ginseng comparing solution (18.4) , appearance fluid (20.1) , blank solution (20.1) reach water (the instrument is corrective at 0 o'clock fluid) in canal of colorimetric of 25 ML of park of each 5.0 ML, join a phenolphthalein to indicate fluid (18.2.5) , solution of the acid that use second (18.2.7) slow shift comes colorless, add solution of amortize of 4.0 ML phosphoric acid (18.2.3) with solution of T of 0.3 ML chloric amine (18.2.4) , shake up, quiet place 3 Min, add 5.0 ML pyridine - solution of ketone of Bi Zun Lin (18.2.6) , shake up, quiet place 20 Min, add water to scale, shake up. Spectrophotometer is in at 620 Nm, with pool of 1 Cm colorimetric, determine after absorbance is worth, compare.
21 qualitative decide
When the absorbance that should deduct absorbance of blank appearance fluid to be worth ≥ ginseng to compare solution is worth, namely Tie La has check to go out, conversely, la Wei check gives iron.
The ration of 22 methods is restricted
It is 10.0 G when quantity weighing appearance, distillation flask moves take a quantity to be 50 ML, when the bulk that decide a look is 100 ML, tie La's ration is restricted to be 3 Mg/kg.
23 art are green decide integratedly
This method through determining the lead in tea is mixed chromic acerbity root, decide whether is chromic acerbity lead contained in tea. When check of chromic acerbity lead goes out, need is qualitative determine the Tie La in tea, when Tie La check goes out, decide painting is contained in tea green. The art in tea is green express with the content of chromic acerbity lead, according to the content of acerbity lead of 8.2 computation chromium, show the content with the green art in tea thereby.
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