CN102441003A - Accurate measurement method for adsorption rate and desorption rate of montmorillonite - Google Patents

Abstract

The invention discloses an accurate measurement method for the adsorption rate and the desorption rate of montmorillonite. In the invention, the absorption effect of the montmorillonite can be reflected by the mode that the montmorillonite absorbs methylene blue standard solution. In the invention, the preprocessing process of the montmorillonite is particularly pointed out, so that the special measurement method is improved, and the computing method of the adsorption rate and the desorption rate is determined. The method disclosed by the invention has the advantages that the sensitivity is high, the absorption effect of the modified montmorillonite under a physiological condition can be accurately reflected, and the quality of the montmorillonite can be more effectively controlled by accurately monitoring the desorption rate.

Description

A kind of Montmorillonitum adsorption rate is conciliate the accurate measuring method of adsorption rate

Technical field

The present invention relates to a kind of detection method of material medicine, particularly a kind of Montmorillonitum adsorption rate is conciliate the accurate measuring method of adsorption rate.

Background technology

Utilizing the detoxification of feedstuff adsorbent is the rather effectively means of mycotoxin molecule, minimizing toxin adverse effect of catching, a large amount of both at home and abroad reports, and interpolation hydrated aluminum silicate calcium can significantly alleviate the adverse effect of mycotoxin.Montmorillonitum is unique a kind of kind that is developed into feed additive by people's medicine.Montmorillonitum is under the jurisdiction of the dioctahedron subtribe in the smectite family, can be divided into calcium type, magnesium type, potassium type and sodium type according to its main electric charge and institute's containing metal, is the main constituent of bentonite and bleaching earth.According to the experiment in vitro of Jaynes in 2007 etc., Montmorillonitum is to mycotoxin, particularly AFB ₁Absorption affinity is relevant with its state of charge, and the Montmorillonitum of low state of charge is poorer than the Montmorillonitum absorption affinity of high state of charge.Absorption affinity is unique in a Montmorillonitum drug standard index of reacting the Montmorillonitum absorption property, and the height of absorption affinity is directly connected to the use curative effect of medicinal smectite.

The Montmorillonitum drug standard of China starts from 1999 (national drug standards .WS-407 of State Food and Drug Administration (X-351)-99); The back has carried out revising (the national drug standards .WS1-of State Food and Drug Administration (X-165)-2004Z) in 2004 to it; Two editions Montmorillonitum standards are stipulated with regard to four aspects of evaluation, composition, performance indications, sanitary index of Montmorillonitum respectively, see table 1 for details.

Table 11999 edition Montmorillonitum drug standard and 2004 editions Montmorillonitum drug standard contrast tables

Annotate: 1. the swelling degree method of testing is had any different.

Two editions Montmorillonitum drug standards of relative analysis; The majority parameters of Montmorillonitum drug standard is like solute, loss on drying, swelling degree, granularity, PH, heavy metal, arsenic salt etc. in evaluation, the water, and common bentonite raw ore also can meet through simple process.And the key index of the quality control of medicinal smectite, in 1999 editions Montmorillonitum drug standards mainly with Al ₂O ₃And SiO ₂Content, two indexs of absorption affinity realize; 2004 editions Montmorillonitum drug standards then are to have increased " impurity peaks intensity must not be higher than Montmorillonitum 0.45nm place characteristic peak in the smectite X-ray diffraction map " newly, through the regulation of impurity content is controlled the Montmorillonitum impurity content.But the leading indicator absorption affinity of reflection smectite content still has problems in the Montmorillonitum drug standard.

Two editions Montmorillonitum drug standards stipulate that all the medicinal smectite absorption affinity should be at 0.30～0.50g/g; Detection method all is to detect the ability of Montmorillonitum absorption sulphuric acid strychnine, and this assay method is more accurate, but the sulphuric acid strychnine belongs to toxic articles; Buy, manage, use inconvenience, and price is high.Patent documentation " a kind of medicinal smectite and preparation absorption affinity assay method thereof ": CN101126708A; On February 20th, 2008 is open; Proposed to measure absorbability with methylene blue, and need not react and heating operation with tetrasodium pyrophosphate, this method stability is high; Practicality is fine in practice, but mainly there is the deficiency of following four aspects in this method:

One, do not consider of the influence of water-insoluble magnesium mineral impurity to absorption affinity.The water-insoluble magnesium class of non-Montmorillonitum dirt also has absorption affinity to methylene blue in the mineral; The deviation that causes the Montmorillonitum absorption affinity to measure; Magnesium quasi-mineral impurity is measured the result to " absorption affinity " of methylene blue and is seen the following form shown in 2, can find out that therefrom magnesium chloride is minimum to the absorption affinity of methylene blue.

The water-insoluble magnesium class of table 2 mineral " absorption affinity " are measured the result

Two, all use the method representation Montmorillonitum absorption property of g/g in this patent and the national standard.The scope of this method for expressing is between 0.23-0.48g/g; Even the methylene blue adsorbance there are differences in the mensuration process; Or with the naked eye can both observe the difference of absorption the time, but difference is little or can not show on the absorption affinity value, mainly is the absorption affinity computing formula

In, A ₂Amplitude of variation and absorption affinity amplitude of variation are seriously uneven, as shown in table 3 below, A ₂Value changed 67.7% o'clock, and the absorption affinity value only changes 2.3%.So the method for expressing of necessary change absorption affinity, the present invention substitutes with adsorption rate after the absorption affinity, and sensitivity that absorbability is measured and accuracy improve, and the variation of adsorptive value between 0.002 can embody on adsorption rate.

The corresponding relation of table 3 adsorption rate and absorption affinity method for expressing

Three, along with further investigation to the Montmorillonitum medicine; The too low exploitation that also restricts the higher Montmorillonitum of purity of absorption affinity scope bound in the standard, because Montmorillonitum is purified to more than 96%, absorption affinity can reach 0.50g/g; Absorption affinity when if Montmorillonitum purity is higher then can rise to greater than 0.50g/g; And do not meet standard-required, therefore have to take measures to reduce Montmorillonitum purity or absorption affinity, patent documentation " a kind of method for preparing of low adsorption force smectite "; Publication number: CN101664674A; On March 10th, 2010 is open, has proposed a kind ofly when making absorption affinity greater than 0.50g/g because of smectite content is too high, reduces the method for the absorption affinity of pharmaceutical Montmorillonitum through modes such as heat treatments.Scope for absorption affinity is formulated 2004 editions standards and 1999 editions conformances to standard; Past 1999 to 2010 11 years; The Montmorillonitum purification technique has obtained greatly developing; Smectite content is greater than the industrialization of the purifying technology more than 95%, medicinal smectite ought to adopt purity greater than more than 95%, high-purity montmorillonite that absorption affinity is strong is raw material, and the absorption affinity higher limit of 0.50g/g has hindered the development of high-purity Montmorillonitum.Use instead after adsorption rate representes, the adsorption rate excursion is equivalent to absorption affinity 0-0.55g/g at 0-100%.

Four, Montmorillonitum contacts the back adsorption time to be defined as 2h more reasonable with methylene blue.Test through a large amount of adsorption dynamics adsorption kinetics and saturated extent of adsorption, we confirm that adsorption time has considerable influence to adsorption rate, this and document " research of modified montmorillonite used absorption methylene blue "; Horse Yulong etc., " silicate journal ", the 32nd the 8th phase of volume; The 970-974 page or leaf, in August, 2004, in research be consistent; Adsorb behind each adsorbent 2h and tend to balance, it is bigger to adopt the method that contacts 1h to control punctual deviation ratio on the one hand, and the 2nd, equilibrium adsorption more can be represented the real adsorption rate of Montmorillonitum.The present invention also optimizes buffer system, and the stability of mensuration improves greatly.

Summary of the invention

A kind of Montmorillonitum adsorption rate of the present invention is conciliate the accurate measuring method of adsorption rate, and main determination step is:

(1) (GB/T12496.10-1999) preparing mass fraction by State Standard of the People's Republic of China's " mensuration of wood activated charcoal test method methylene blue adsorption value " is 0.2% methylene blue titer; And demarcate by its said method, the demarcation concentration records is C%;

(2) it is an amount of to get 0.2% methylene blue titer, adds the solution that phosphate buffer (pH6.8) is processed 2 μ g/mL, according to two appendix IV of Chinese Pharmacopoeia version in 2010 spectrophotography A method, under 665nm, writes down this solution absorbency A ₁

(3) by " People's Republic of China's veterinary drug allusion quotation " appendix preparation phosphate buffer (pH6.8): get 0.2mol/L potassium dihydrogen phosphate 250ml, add 0.2mol/L sodium hydroxide solution 118ml and be diluted with water to 1000ml;

(4) accurately take by weighing the 0.1000g Montmorillonitum that is dried to constant weight, put in the tool plug conical flask, add 1mol/L hydrochloric acid solution 5ml washing; Centrifugal and abandoning supernatant, after adding distil water is washed 2 times, accurate phosphate buffer (pH6.8) 10mL that adds in deposition; Jolting 1h carries out next step behind the placement 24h;

(5) the accurate methylene blue solution 25ml that adds 0.2% (W/V) in above-mentioned solution puts 37 ℃, carries out next step behind the jolting 2h;

(6) filter above-mentioned mixed solution with exsiccant middling speed filter paper, filter paper and the safe placement of deposition, pending desorption power is measured;

(7) precision is measured subsequent filtrate 10mL, puts in the 250mL measuring bottle, adds phosphate buffer (pH6.8) and is diluted to scale; Shake up, observe the color of solution, as consistent with 2 μ g/mL methylene blue solution colors; Stop dilution,, measure absorbance A at the 665nm place according to above-mentioned spectrophotography ₂, as bigger with 2 μ g/mL methylene blue solution color distortions, the scalable extension rate makes absorbance A ₂Value and A ₁Close;

(8) adsorption rate of various Montmorillonitum absorption methylene blues is to calculate by following formula:

$A_{\mathrm{\τ}}=\frac{({\mathrm{\ρ}}_o-{\mathrm{\ρ}}_e)*0.1}{{\mathrm{\ρ}}_o*M}\×100\%$

In the formula: A _τBe the adsorption rate of Montmorillonitum,

ρ _eThe methylene blue mass concentration (mg/L) that supernatant is not adsorbed when being adsorption equilibrium equals 2 μ g/mL*C%,

ρ _oBe the mass concentration (mg/L) that does not add the methylene blue of Montmorillonitum adsorbent, if measure A ₂Before, it has diluted N doubly, then

M is actual sample weighting amount.

Described Montmorillonitum absorption affinity is carried out the acidification of Montmorillonitum earlier with 1mol/L hydrochloric acid before measuring.

Described Montmorillonitum is to put 37 ℃ to Montmorillonitum and the methylene blue handled well jointly, jolting 2h when the absorption methylene blue.

Described a kind of Montmorillonitum adsorption rate is conciliate in the accurate measuring method of adsorption rate, representes the absorbability of Montmorillonitum to the absorption methylene blue with adsorption rate.

Described a kind of Montmorillonitum adsorption rate is conciliate in the accurate measuring method of adsorption rate; Desorption rate determination step is: the deposition after filtering during absorption affinity is measured is put into phosphate buffer (pH6.8) together with filter paper; Put 37 ℃; Jolting 2h with the centrifugal 5min of 4000rpm, gets supernatant and measures absorbance A at the 665nm place ₃, calculate adsorption rate by following formula:

$D_{\mathrm{\τ}}=\frac{{\mathrm{\ρ}}_{\mathrm{\φ}}*0.1}{{\mathrm{\ρ}}_l*M}\×100\%$

In the formula: D _τBe the desorption rate of Montmorillonitum,

ρ _φThe methylene blue mass concentration (mg/L) that discharges in the supernatant when being dissociation equilibrium, here according to the contrast solution light absorption value, the blue mass concentration of the supernatant subunit after the computational solution adsorption equilibrium: 2 μ g/mL*C%*A ₃/ A ₁

ρ _lBe the mass concentration (mg/L) of Montmorillonitum adsorbent methylene blue, equal ρ _o-ρ _e,

M is actual sample weighting amount.

The invention has the beneficial effects as follows: the assay method that Montmorillonitum adsorption rate of the present invention is conciliate adsorption rate carries out acid treatment to raw material earlier, removes the influence of magnesium to absorption affinity; Use the buffer environment of phosphate buffer (pH6.8) as reaction then, behind Montmorillonitum to be measured and the methylene blue reaction 2h, with spectrophotometry absorption methylene blue ratio, computational methods method accuracy, sensitivity than before improve greatly; And set up the assay method of understanding adsorption rate simultaneously, reflected the absorbability of Montmorillonitum accurately.

The specific embodiment

Following examples are that ability technical staff should be appreciated that following description shall not be applied to restriction protection scope of the present invention in order to the explanation preferred embodiment of the invention.

Embodiment 1: the Montmorillonitum adsorption rate is conciliate the mensuration of adsorption rate

The mensuration of 1 contrast solution light absorption value:

Get 0.2% methylene blue titer 10ml and add phosphate buffer (pH6.8) 10L, obtain the solution of 2 μ g/mL,, under 665nm, write down this solution absorbency A according to two appendix IV of Chinese Pharmacopoeia version in 2010 spectrophotography A method ₁This time get A ₁Be 0.317, methylene blue is through demarcating, and concentration is 0.2%*68%=1.36%, and the solution actual concentrations of the 2 μ g/mL that obtain after the process dilution is 1.36 μ g/mL.

2 reduce the interferential acidification of magnesium ion:

Accurately take by weighing the 0.1003g Montmorillonitum that is dried to constant weight, put in the tool plug conical flask, added 1mol/L hydrochloric acid 5ml washing, centrifugal and abandoning supernatant, adding distil water is washed 2 times.

The mensuration of 3 Montmorillonitum adsorption rates and absorption affinity:

In the deposition after acidification, accurate phosphate buffer (pH6.8) 10mL that adds, jolting 1h, the accurate methylene blue solution 25ml that adds 0.2% (W/V) puts 37 ℃, jolting 2h behind the placement 24h; Filter above-mentioned mixed solution with exsiccant middling speed filter paper, filter paper and the safe placement of deposition, pending desorption power is measured; Precision is measured subsequent filtrate 10mL according to above-mentioned spectrophotography, measures absorbance A at the 665nm place ₂, record A here ₂Be 0.102, calculate the adsorption rate of various Montmorillonitum absorption methylene blues by following formula:

$A_{\mathrm{\τ}}=\frac{({\mathrm{\ρ}}_o-{\mathrm{\ρ}}_e)*0.1}{{\mathrm{\ρ}}_o*M}\×100\%$

In the formula: A _τBe the adsorption rate of Montmorillonitum,

ρ _eThe methylene blue mass concentration (mg/L) that supernatant is not adsorbed when being adsorption equilibrium, here according to the contrast solution light absorption value, the supernatant methylene blue mass concentration after the calculating adsorption equilibrium is 1.36*0.102/0.317=0.438mg/L.

ρ _oBe the mass concentration (mg/L) that does not add the methylene blue of Montmorillonitum adsorbent, be 1.36mg/L here.

M is actual sample weighting amount, is 0.1003g here;

Calculate A _τ=(1.36-0.438) * 0.1/0.1003/1.36*100%=67.59%

Assay method by absorption affinity is measured, and measures the result to be:

4, the mensuration of Montmorillonitum desorption rate

The Montmorillonitum of absorption methylene blue filters the filter paper of usefulness, puts into phosphate buffer (pH6.8) together, puts 37 ℃, and jolting 2h with the centrifugal 5min of 4000rpm, gets supernatant and measures absorbance A at the 665nm place ₃, record absorbance A here ₃Be 0.015, calculate adsorption rate by following formula:

$D_{\mathrm{\τ}}=\frac{{\mathrm{\ρ}}_{\mathrm{\φ}}*0.1}{{\mathrm{\ρ}}_l*M}\×100\%$

In the formula: D _τBe the desorption rate of Montmorillonitum,

ρ _φThe methylene blue mass concentration (mg/L) that discharges in the supernatant when being dissociation equilibrium, here according to the contrast solution light absorption value, the blue mass concentration of the supernatant subunit after the computational solution adsorption equilibrium is 2 μ g/mL*C%*A ₃/ A ₁=1.36*0.015/0.317=0.064mg/L,

ρ _lBe the mass concentration (mg/L) of Montmorillonitum adsorbent methylene blue, equal ρ _o-ρ _e=1.36-0.438=0.922, M are actual sample weighting amount.

D _τ＝0.064*0.1/0.922/0.1003*100％＝6.9％

Embodiment 2: the comparison that Montmorillonitum adsorption rate and absorption affinity are measured

1 Montmorillonitum adsorption rate, desorption rate test method

1.1 the mensuration of contrast solution light absorption value

It is an amount of to get 0.2% methylene blue titer, adds the solution that phosphate buffer (pH6.8) is processed 2 μ g/mL, according to two appendix IV of Chinese Pharmacopoeia version in 2010 spectrophotography A method, under 665nm, writes down this solution absorbency A ₁

1.2 reduce the interferential acidification of magnesium ion

Accurately take by weighing 0.1000g Montmorillonitum that is dried to constant weight or the sample that contains 0.1000g Montmorillonitum preparation; Put in the tool plug conical flask; Add 1mol/L hydrochloric acid (it is that concentration is 1mol/L that the 86.9ml concentrated hydrochloric acid is made into 1000ml) 5ml washing, centrifugal and abandoning supernatant, adding distil water is washed 2 times.

1.3 the mensuration of Montmorillonitum absorption affinity

In the deposition after acidification, accurate phosphate buffer (pH6.8) 10mL that adds, jolting 1h, the accurate methylene blue solution 25ml that adds 0.2% (W/V) puts 37 ℃, jolting 2h behind the placement 24h; Filter above-mentioned mixed solution with exsiccant middling speed filter paper, filter paper and the safe placement of deposition, pending desorption power is measured; Precision is measured subsequent filtrate 10mL, puts in the 250mL measuring bottle, adds phosphate buffer (pH6.8) and is diluted to scale; Shake up, observe the color of solution, as consistent with 2 μ g/mL methylene blue solution colors; Stop dilution,, measure absorbance A at the 665nm place according to above-mentioned spectrophotography ₂, as bigger with 2 μ g/mL methylene blue solution color distortions, the scalable extension rate makes absorbance A ₂Value and A ₁Close; Calculate the adsorption rate of various Montmorillonitum absorption methylene blues by following formula:

$A_{\mathrm{\τ}}=\frac{({\mathrm{\ρ}}_o-{\mathrm{\ρ}}_e)*0.1}{{\mathrm{\ρ}}_o*M}\×100\%$

In the formula: A _τBe the adsorption rate of Montmorillonitum,

ρ _eThe methylene blue mass concentration (mg/L) that supernatant is not adsorbed when being adsorption equilibrium equals 2 μ g/mL*C%,

ρ _oBe the mass concentration (mg/L) that does not add the methylene blue of Montmorillonitum adsorbent, if measure A ₂Before, it has diluted N doubly, then

M is actual sample weighting amount;

2 Montmorillonitum desorption are conciliate adsorption rate and are measured instance

Get each 0.1000g of Montmorillonitum raw material of 6 parts of separate sources, the accurate title, decide, and carries out the mensuration that adsorption rate is conciliate adsorption rate according to above-mentioned " 1 Montmorillonitum adsorption rate experimental technique " and " mensuration of 2 Montmorillonitum desorption power ", and the result sees the following form 5.Carried out the aflatoxin absorption affinity of same sample simultaneously and measured, measurement result sees Table 5.

The mensuration result of table 5 Montmorillonitum sample absorption affinity, adsorption rate, desorption rate

Can find out from table 5, the adsorption rate of Montmorillonitum and better to the absorbability dependency of aflatoxin, absorption affinity can not demonstrate fully the absorbability of Montmorillonitum to mycotoxin.

Annotate: the solution preparation

0.2% methylene blue titer: be taken at 93 ℃ ± 2 ℃ oven dry 4h methylene blue 1.00g, the water solution transfer is to the brown volumetric flask of 500ml, and thin up shakes up to scale, uses behind the placement 24h.

Phosphate buffer (pH6.8): get 0.2mol/L potassium dihydrogen phosphate 250ml, add 0.2mol/L sodium hydroxide solution 118ml and be diluted with water to 1000ml.

Claims (2)

1. a Montmorillonitum adsorption rate is conciliate the accurate measuring method of adsorption rate, it is characterized in that determination step comprises:

(1) (GB/T12496.10-1999) preparing mass fraction by State Standard of the People's Republic of China's " mensuration of wood activated charcoal test method methylene blue adsorption value " is 0.2% methylene blue titer; And demarcate by its said method, the demarcation concentration records is C%;

(2) it is an amount of to get 0.2% methylene blue titer, adds the solution that phosphate buffer (pH6.8) is processed 2 μ g/mL, according to two appendix IV of Chinese Pharmacopoeia version in 2010 spectrophotography A method, under 665nm, writes down this solution absorbency A ₁

(3) by " People's Republic of China's veterinary drug allusion quotation " appendix preparation phosphate buffer (pH6.8): get 0.2mol/L potassium dihydrogen phosphate 250ml, add 0.2mol/L sodium hydroxide solution 118ml and be diluted with water to 1000ml;

(4) accurately take by weighing the 0.1000g Montmorillonitum that is dried to constant weight, put in the tool plug conical flask, add 1mol/L hydrochloric acid solution 5ml washing; Centrifugal and abandoning supernatant, after adding distil water is washed 2 times, accurate phosphate buffer (pH6.8) 10mL that adds in deposition; Jolting 1h carries out next step behind the placement 24h;

(5) the accurate methylene blue solution 25ml that adds 0.2% (W/V) in above-mentioned solution puts 37 ℃, carries out next step behind the jolting 2h;

(6) filter above-mentioned mixed solution with exsiccant middling speed filter paper, filter paper and the safe placement of deposition, pending desorption power is measured;

(7) precision is measured subsequent filtrate 10mL, puts in the 250mL measuring bottle, adds phosphate buffer (pH6.8) and is diluted to scale; Shake up, observe the color of solution, as consistent with 2 μ g/mL methylene blue solution colors; Stop dilution,, measure absorbance A at the 665nm place according to above-mentioned spectrophotography ₂, as bigger with 2 μ g/mL methylene blue solution color distortions, the scalable extension rate makes absorbance A ₂Value and A ₁Close;

(8) adsorption rate of various Montmorillonitum absorption methylene blues is to calculate by following formula:

In the formula: A _τBe the adsorption rate of Montmorillonitum,

ρ _eThe methylene blue mass concentration (mg/L) that supernatant is not adsorbed when being adsorption equilibrium equals 2 μ g/mL*C%,

ρ _oBe the mass concentration (mg/L) that does not add the methylene blue of Montmorillonitum adsorbent, if measure A ₂Before, it has diluted N doubly, then

M is actual sample weighting amount.

2. a Montmorillonitum adsorption rate is conciliate the accurate measuring method of adsorption rate; It is characterized in that said desorption rate determination step is: the deposition after filtering during adsorption rate is measured is put into phosphate buffer (pH6.8) together with filter paper; Put 37 ℃; Jolting 2h with the centrifugal 5min of 4000rpm, gets supernatant and measures absorbance A at the 665nm place ₃, calculate adsorption rate by following formula:

In the formula: D _τBe the desorption rate of Montmorillonitum,

ρ _φThe methylene blue mass concentration (mg/L) that discharges in the supernatant when being dissociation equilibrium, here according to the contrast solution light absorption value, the blue mass concentration of the supernatant subunit after the computational solution adsorption equilibrium is 2 μ g/mL*C%*A ₃/ A ₁=1.36*0.015/0.317=0.064mg/L,

ρ _lBe the mass concentration (mg/L) of Montmorillonitum adsorbent methylene blue, equal ρ _o-ρ _e,

M is actual sample weighting amount.