CN102288693A - Method for detecting selenomethionine (SeMet) in selenium-enriched yeast - Google Patents
Method for detecting selenomethionine (SeMet) in selenium-enriched yeast Download PDFInfo
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Abstract
The invention discloses a method for detecting selenomethionine (SeMet) in selenium-enriched yeast and belongs to the technical field of food analysis. The method comprises the following main steps of: (1) performing enzymolysis on combined SeMet in the selenium-enriched yeast; (2) derivating the SeMet through dansyl chloride serving as a derivating agent; and (3) separating and measuring components of derivating liquid by a high performance liquid chromatography-fluorescence detection (HPLC-FLD) method, and calculating content of the SeMet in a sample by an external standard method. Enzymolysis conditions and parameters in the derivatization process are optimized, the technical problem of extracting and derivating the SeMet in the selenium-enriched yeast is solved, the HPLC-FLD method for detecting the SeMet in the selenium-enriched yeast is established, and an accurate, easy and economic effective method is provided for quality evaluation of the selenium-enriched yeast.
Description
Technical field
The invention belongs to the food analysis field, relate to a kind of high performance liquid chromatography (HPLC) method of measuring selenomethionine in the Se-enriched yeast.
Background technology
Functional yeast refers to screen suitable barms, by controlling its growing environment, makes the yeast class of certain in enriched medium nutrient and be converted into the sp act material that certain class crowd needs through the yeast internal metabolism in growth course.The most ripe domestic functional yeast product is a Se-enriched yeast at present, it selects saccharomyces cerevisiae (Saccharomyces cerevisiae) for use, and in nutrient culture media, adding inorganic selenium preparation such as selenite aborning, yeast obtains and is translated into the organic selenium that mainly exists with the selenomethionine form (organic selenium refer to combine or participate in biomacromolecule the selenium that biomacromolecule is synthesized) behind the inorganic selenium; Again because of organic selenium than the easier utilization that is absorbed by the body of inorganic selenium, spinoff still less, Se-enriched yeast therefore become contemporary selenium-rich nutritive replenishers produce in best raw material.
Selenomethionine is not only the abundantest selenide of content in the Se-enriched yeast, and selenium content accounts for the total Se content 60-80% of yeast, and it also is the highest selenide of biological effectiveness that studies confirm that simultaneously.Be converted into selenocystein through changeing the selenium approach after selenomethionine is absorbed by the body or earlier, be reduced to hydrogen selenide through β-lyases again, selenium hydride then or as selenoprotein in the active precursor participation body synthesizes, or is excreted after the biological methylation reaction generates monomethyl selenium, two methyl selenium and trimethyl selenium; Or when the selenomethionine excess intake, form active selenium intermediate methyl selenol (CH3SeH) through γ-lyases reduction; Or replace methionine randomly and participate in the synthetic of body protein, it replaces the ratio that frequency depends on selenomethionine and methionine in the food; Or selenium is discharged, and participate in the synthetic of selenoenzyme by changeing selenium approach or γ-cracking reaction as the storage form of selenium mode when body is taken in the selenium amount and reduced with protein degradation.Research thinks that because of the character of selenium element and element sulphur is close, yeast can be used for it biosynthesizing of methionine and then generate selenomethionine as the alternative of element sulphur absorb the selenium element from environment after, and the frequency of replacement depends on the concentration of selenium in the yeast body.The concentration of selenomethionine is an important reaction of its quality and nutritive value in the Se-enriched yeast, and this just need carry out compartment analysis and detection by quantitative to the selenomethionine in the Se-enriched yeast.
Because Se-enriched yeast matrix complexity and selenomethionine are oxidized easily, have increased wherein the extraction difficulty and the detection difficulty of selenomethionine.Generally adopt HPLC-ICP-MS method, HPLC-ESI-MS/HPLC-ESI-MS/MS method Se-enriched yeast to be carried out the morphological analysis of selenium in the research at present, harsh to the instrument and equipment conditional request, the experimental cost costliness is difficult to adapt to laboratory conventional sense requirement, and method is difficult for popularizing.Therefore, it is very necessary to study and set up the detection method of selenomethionine in a kind of accurate, easy, economic and Se-enriched yeast of being easy to promote.
Cited literature 2:
1.Aleksandra?Polatajko，Magdalena?Sliwka-Kaszynska，Mihaly?Dernovics，Rafal?Ruzik，Jorge?Ruiz?Encinar?and?Joanna?Szpunar.A?systematic?approach?to?selenium?speciation?in?selenized?yeast[J].Journal?of?Analytical?Atomic?Spectrometry，2004，19(1)：114-120.
2.H.Chassaigne，C.C.Chéry，G.Bordin，A.R.Rodriguez.Development?of?new?analytical?methods?for?selenium?speciation?in?selenium-enriched?yeast?material[J].Journal?of?Chromatography?A，976(2002)，409-422.
3.Susan?M.bird，Peter?C?Uden，Jullan?F.Tyson，Eric?Block，Eric?Denoyer.Speciation?of?Selenoamino?Acids?and?Organoselenium?Compounds?in?Selenium-enriched?Yeast?Using?High-performance?Liquid?Chromatography-Inductively?Coupled?Plasma?Mass?Spectrometry[J].Journal?of?Analytical?Atomic?Spectrometry，July?1997，Vol.12(785-788).
4.Laura?Hinojosa?Reyes，Jorge?Ruiz?Encinar，Juan?Manuel?Marchante-Gayón，JoséIgnacio?García?Alonso，Alfredo?Sanz-Medel.Selenium?bioaccessibility?assessment?in?selenized?yeast?after“in?vitro”gastrointestinal?digestion?using?two-dimensional?chromatography?and?mass?spectrometry[J].Journal?of?Chromatography?A，1110(2006)108-116.
5.Zoyne?Pedrero，Yolanda?Madrid.Novel?approaches?for?selenium?speciation?in?foodstuffs?and?biological?specimens：A?review[J].Analytica?Chimica?Acta?634(2009)135-152.
6.Johann?Far，Hugues?Preud’homme，Ryszard?Lobinski.Detection?and?identification?of?hydrophilic?selenium?compounds?in?selenium-rich?yeast?by?size?exclusion-microbore?normal-phase?HPLC?with?the?on-line?ICP-MS?and?electrospray?Q-TOF-MS?detection[J].Analytica?Chimica?Acta?657(2010)175-190.
7.Peter?C.Uden，Harriet?Totoe?Boakye，Chethaka?Kahakachchi，Julian?F.Tyson.Selective?detection?and?identification?of?Se?containing?compounds-review?and?recent?developments[J].Journal?of?Chromatography?A，1050(2004)85-93.
8.Erik?H.Larsen，Marianne?Hansen，Teresa?Fan，Martin?Vahl.Speciation?of?selenoamino?acids，selenonium?ions?and?inorganic?selenium?by?ion?exchange?HPLC?with?mass?spectrometric?detection?and?its?application?to?yeast?and?algae[J].J.Anal.At.Spectrom.，2001，16，1403-1408.
9.L.Hinojosa.Reyes，F.MorenoSanz，P.HerreroEspílez，J.M.Marchante-Gayón，J.I.García?Alonso，A.Sanz-Medel.Biosynthesis?of?isotopically?enriched?selenomethionine：application?to?its?accurate?determination?in?selenium-enriched?yeast?by?isotope?dilution?analysis?HPLC-ICP-MS[J].J.Anal.At.Spectrom.，2004，19，1230-1235.
10.Corinne?Casiot，Veronique?Vacchina，Hubert?Chassaigne，Joanna?Szpunar，Martine?Potin-Gautier，Ryszard
.An?approach?to?the?identification?of?selenium?species?in?yeast?extracts?using?pneumatically-assisted?electrospray?tandem?mass?spectrometry[J].Anal.Commun.，1999，36，77-80.
11.Corinne?Casiot，Joanna?Szpunar，Ryszard
，Martine?Potin-Gautier.Sample?preparation?and?HPLC?separation?approaches?to?speciation?analysis?of?selenium?in?yeast?by?ICP-MS[J].J.Anal.At.Spectrom.，1999，14，645-650.
12.Erik?H.Larsen，Jens?Sloth，Marianne?Hansena，Sven?Moesgaard.Selenium?speciation?and?isotope?composition?in?
77Se-enriched?yeast?using?gradient?elution?HPLC?separation?and?ICP-dynamic?reaction?cell-MS[J].J.Anal.At.Spectrom.，2003，18，310-316.
Summary of the invention
The present invention has developed the detection method of selenomethionine in a kind of Se-enriched yeast, this method adopts dansyl Cl column front derivation high performance liquid chromatography-fluorescence method (HPLC-FLD) to detect selenomethionine in Se-enriched yeast, thereby provides a kind of facility, effective means with quality assessment for the nutrition of Se-enriched yeast.Characteristics such as this method has accurately, economic, easy, highly sensitive, good reproducibility, precision height.
The invention provides the detection method of selenomethionine in a kind of Se-enriched yeast, comprising:
(1) adopt physical method to destroy the cell membrane of Se-enriched yeast, take by weighing 0.1g Se-enriched yeast powder in vial, add 5mL 0.05-1.0%DTT (w/v) 0.05mol/L phosphate buffer (pH7.4), the 40mg pronase, in 37 ℃ of shaking table jolting reaction 24h, treat that enzymolysis liquid is cooled to room temperature, in enzymolysis liquid, add protein precipitant, in the centrifugal 10min of 3000rpm, get the supernatant analysis behind the abundant mixing;
(2) get 200 μ L supernatants, add the 1.80mL sodium carbonate buffer, 1mL 6000mg/L dansyl Cl solution in 60 ℃ of water-baths 2h that derives, adds 0.1mL 20mg/mL methylamine hydrochloride solution and finishes derivatization reaction, and 15min is left standstill at the place in lucifuge;
(3) high performance liquid chromatography carries out the component separation to the liquid of deriving, and fluorescence detector detects, and adopts external standard method to calculate the content of selenomethionine:
Se-enriched yeast enzymolysis liquid after deriving sample introduction behind filtering with microporous membrane is measured.Described high performance liquid chromatograph adopts C18 post (250mm * 4.6mm, particle diameter 5 μ m), 30 ℃ of column temperature; Sample size 10 μ L; Gradient elution, elution program such as table 1:
Table 1 gradient elution program
Annotate: A be the 10mM phosphate buffer (4%N, dinethylformamide, pH6.55); B is an acetonitrile, and the moving phase ratio is percent by volume in the table;
Selenomethionine appearance time: 29～31min.
In the step (1), mortar ground wall-breaking method after described cell physical wall breaking method was meant liquid nitrogen frozen;
In the step (1), the concentration of DDT is 0.05-1.0% in the described phosphate buffer, and optium concentration is 0.1%.
In the step (1), described protein precipitant is 0.1mL 1.5g/mL potassium ferrocyanide and 0.1mL 3g/mL zinc acetate.
In the step (2), described derivatization conditions is for adding the 1mL sodium carbonate buffer, and 1mL 6000mg/L dansyl Cl derivative solution is in 60 ℃ of water-baths 2h that derives.
Particularly, the detection method of selenomethionine in a kind of Se-enriched yeast provided by the present invention, performing step is as follows:
(1) enzymolysis and extraction of rich selenium propylhomoserin in the yeast: adopt mortar grinds behind the first liquid nitrogen frozen mode to destroy the cell membrane of Se-enriched yeast, take by weighing 0.1g Se-enriched yeast powder in vial, add 5mL 0.1%DTT (w/v) 0.05mol/L phosphate buffer (pH7.4), the 40mg pronase, in 37 ℃ of shaking table jolting reaction 24h, treat that enzymolysis liquid is cooled to room temperature, in enzymolysis liquid, add 0.1mL 1.5g/mL potassium ferrocyanide, 0.1mL 3g/mL zinc acetate, in the centrifugal 10min of 3000rpm, get supernatant and continue to analyze behind the abundant mixing;
(2) enzymolysis liquid is derived: get 200 μ L supernatants, add the 1.8mL sodium carbonate buffer, 1mL 6000mg/L dansyl Cl derivative solution in 60 ℃ of water-baths 2h that derives, adds 0.1mL 20mg/mL methylamine hydrochloride solution and finishes derivatization reaction, and 15min is left standstill at the place in lucifuge;
Though selenomethionine does not have fluorescent characteristic, can generate derivative products with the dansyl Cl reaction with fluorescent characteristic.The dansyl Cl selenomethionine reaction equation of deriving:
(3) chromatographic resolution and mensuration: the liquid sample introduction behind filtering with microporous membrane of deriving is measured, and external standard method is calculated selenomethionine and contained.High performance liquid chromatograph adopts C
18Post (250mm * 4.6mm, particle diameter 5 μ m), column temperature: 30 ℃; Sample size 10 μ L; The gradient elution program sees Table 1 amount.
This method adopts specific separation condition to realize the effective separation and the assay of selenomethionine in the Se-enriched yeast, utilizes external standard method gained typical curve, the peak area of selenomethionine and the coefficient R between concentration when adopting this method quantitative
2＞0.999
Beneficial effect of the present invention: this method can effectively extract and accurately measure selenomethionine in the Se-enriched yeast.Consistent with external laboratory detection result, used experimental facilities is general, and cost of determination significantly reduces, and can satisfy testing agency and enterprise's laboratory conventional sense requirement, and method is easy to promote.
Description of drawings:
The high-efficient liquid phase chromatogram of Fig. 1 selenomethionine standard items.
The high-efficient liquid phase chromatogram of Fig. 2 embodiment 1 Se-enriched yeast sample.
Fig. 3 selenomethionine chromatographic peak area and concentration correction curve map.
Embodiment:
For a better understanding of the present invention, further set forth the present invention below in conjunction with example.
Adopt high performance liquid chromatograph and fluorescence detector: Waters2695 high performance liquid chromatograph, Waters 2475 fluorescence detectors (U.S. Waters company)
Chromatographic condition: C
18Reversed-phase column (250mm * 4.6mm, particle diameter 5 μ m), 30 ℃ of column temperatures; Fluorescence detector: λ ex=320nm, λ em=523nm, gain is 1; Sample size 10 μ L; The gradient elution program sees Table 1.
The related reagent that adopts:
Selenomethionine (〉=98%, J﹠amp; K, Scientific LTD); Dansyl Cl (〉=98%, Acros Organics); Hydrochloric acid (top grade is pure); Natrium carbonicum calcinatum (analyzing pure); NaOH (analyzing pure); Methylamine hydrochloride (analyzing pure); N, dinethylformamide (analyzing pure); Sodium dihydrogen phosphate (analyzing pure); Acetonitrile (chromatographic grade, Fisher Scientific); Experimental water is a Milli-Q water.
Solution is formulated as follows:
The preparation of standard inventory solution takes by weighing an amount of selenomethionine standard items, makes the selenomethionine standard reserving solution of 1.0mg/L with Milli-Q water.
The preparation of dansyl Cl solution takes by weighing an amount of dansyl Cl, makes the storing solution of 6000mg/L with acetonitrile.
The mensuration of selenomethionine in embodiment 1 Se-enriched yeast
The Se-enriched yeast sample that sample 1 provides for domestic certain yeast manufacturing enterprise, adopt mortar grinds behind the first liquid nitrogen frozen mode to destroy the cell membrane of Se-enriched yeast, take by weighing 0.1g Se-enriched yeast powder in vial, add 5mL 0.1%DTT (w/v) 0.05mol/L phosphate buffer (pH7.4), the 40mg pronase, in 37 ℃ of shaking table jolting reaction 24h, treat that enzymolysis liquid is cooled to room temperature, in enzymolysis liquid, add 0.1mL 1.5g/mL potassium ferrocyanide, 0.1mL 3g/mL zinc acetate, fully behind the mixing in the centrifugal 10min of 3000rpm.
Get the supernatant of the centrifugal back of 200 μ L enzymolysis liquids gained, add the 1.8mL sodium carbonate buffer, 1mL 6000mg/L dansyl Cl derivative solution is in 60 ℃ of water-baths 2h that derives, add 0.1mL 20mg/mL methylamine hydrochloride solution and finish derivatization reaction, 15min is left standstill at the place in lucifuge.
Enzymolysis liquid after deriving sample introduction behind filtering with microporous membrane is measured, and adopts external standard method to calculate the content of selenomethionine.High performance liquid chromatograph adopts C
18Post (250mm * 4.6mm, particle diameter 5 μ m), 30 ℃ of test column temperature; The fluorescence detector gain is 1; Sample size 10 μ L; The gradient elution program sees Table 1.
Selenomethionine appearance time: 29-31min.
The content of selenomethionine is 3760mg/kg in the Se-enriched yeast sample.
Among the above embodiment, carried out method validation:
Preparation series concentration selenomethionine standard operation liquid, the peak face response y of tested component and the relation between the mass concentration x are measured in the sample introduction analysis, get selenomethionine equation of linear regression y=122459x-48813, regression coefficient R
2Be 0.9996, method detects and is limited to 20 μ g/L, quantitatively is limited to 50 μ g/L.
Select the test sample of a kind of Se-enriched yeast as selenomethionine assay method replica test, repeat 6 times and detect, RSD sees Table 2 less than 3.0%.
Carry out the recovery of standard addition test according to 50%, 100%, 150% of selenomethionine content in the Se-enriched yeast.Test findings shows that the method recovery is good, and the average recovery of standard addition of selenomethionine sees Table 3 between 87.91-108.49.
Table 2 selenomethionine precision
Table 3 selenomethionine recovery of standard addition (n=3)
As seen, method of the present invention has the higher precision and the recovery, is fit to the detection of selenomethionine in the Se-enriched yeast.
Claims (5)
1. the detection method of selenomethionine in the Se-enriched yeast is characterized in that:
(1) adopt physical method to destroy the cell membrane of Se-enriched yeast, take by weighing 0.1g Se-enriched yeast powder in vial, add 5mL 0.05mol/L phosphate buffer (pH7.4) and contain 0.05-1.0%DTT (w/v), the 40mg pronase, in 37 ℃ of shaking table jolting 24h, treat that enzymolysis liquid is cooled to room temperature, in enzymolysis liquid, add protein precipitant, in the centrifugal 10min of 3000rpm, get the supernatant analysis behind the abundant mixing;
(2) get 200 μ L supernatants, add the 1.8mL sodium carbonate buffer, 1mL 6000mg/L dansyl Cl derivative solution in 60 ℃ of water-baths 2h that derives, adds 0.1mL 20mg/mL methylamine hydrochloride solution and finishes derivatization reaction, and 15min is left standstill at the place in lucifuge;
(3) high performance liquid chromatography carries out the component separation to the liquid of deriving, and fluorescence detector detects, and adopts external standard method to calculate the content of selenomethionine:
Se-enriched yeast enzymolysis liquid after deriving sample introduction behind filtering with microporous membrane is measured.Described high performance liquid chromatograph adopts C
18Post (250mm * 4.6mm, particle diameter 5 μ m), 30 ℃ of column temperature; Sample size 10 μ L; Gradient elution, elution program such as table 1:
Table 1 gradient elution program
Annotate: A be the 10mM phosphate buffer (4%N, dinethylformamide, pH6.55); B is an acetonitrile, and the moving phase ratio is percent by volume in the table;
Selenomethionine appearance time: 29～31min.
2. method according to claim 1, it is characterized in that: in the step (1), mortar ground wall-breaking method after described cell physical wall breaking method was meant liquid nitrogen frozen;
3. method according to claim 1, it is characterized in that: in the step (1), the concentration of DDT is 0.05-1.0% in the described phosphate buffer, and optium concentration is 0.1%.
4. method according to claim 1, it is characterized in that: in the step (1), described protein precipitant is 0.1mL 1.5g/mL potassium ferrocyanide and 0.1mL 3g/mL zinc acetate.
5. method according to claim 1 is characterized in that: in the step (2), described derivatization conditions is for adding the 1mL sodium carbonate buffer, and 1mL 6000mg/L dansyl Cl derivative solution is in 60 ℃ of water-baths 2h that derives.
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| CN101793642A (en) * | 2009-12-17 | 2010-08-04 | 东北农业大学 | Separation and liquid chromatography column pre-column derivatization method of biogenic amine in soybean paste |
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| CN101793642A (en) * | 2009-12-17 | 2010-08-04 | 东北农业大学 | Separation and liquid chromatography column pre-column derivatization method of biogenic amine in soybean paste |
Non-Patent Citations (3)
| Title |
|---|
| JORGE RULZ ENCLNAR ET AL.: "Determination of Selenomethionine and Selenocysteine in Human Serum Using Speciated Isotope Dilution-Capillary HPLC-Inductively Coupled Plasma Collision Cell Mass Spectrometry", 《ANALYTICAL CHEMISTRY》, vol. 76, no. 22, 15 November 2004 (2004-11-15), pages 6635 - 6642 * |
| 潘红阳等: "反相高效液相色谱法测定富硒脱水菜心中的硒代氨基酸", 《食品与发酵工业》, vol. 34, no. 10, 31 October 2008 (2008-10-31) * |
| 章军等: "反相高效液相色谱法测定深层培养含硒构菌菌丝体中的硒蛋氨酸", 《分析化学》, vol. 23, no. 1, 31 December 1995 (1995-12-31), pages 49 - 51 * |
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