CN110514778B - Method for simultaneously detecting 22 kinds of sugar, sugar alcohol and alcohols in fruit juice - Google Patents

Abstract

The invention discloses a method for simultaneously detecting 22 sugars, sugar alcohols and alcohols in fruit juice, which belongs to the field of analytical chemistry, adopts integral pulse ampere-ion chromatography, researches experimental factors influencing component separation through an optimization pretreatment method, establishes a method for simultaneously detecting 22 sugars, sugar alcohols and alcohols (2, 3-butanediol, propylene glycol, methanol, glycerol, erythritol, xylitol, rhamnose, arabitol, sorbitol, trehalose, dulcitol, mannitol, 2-deoxy-D-glucose, arabinose, melibiose, glucose, galactose, fructose, ribose, sucrose, raffinose and maltose) in fruit juice at one time, solves the technical problem of accurately analyzing the multi-component of the sugars, sugar alcohols and alcohols in the fruit juice, and is rapid, accurate and sensitive, the simultaneous analysis of multiple classes and components is realized, and the important contribution is made to the detection of the juice components.

Description

Method for simultaneously detecting 22 kinds of sugar, sugar alcohol and alcohols in fruit juice

Technical Field

The invention belongs to the field of analytical chemistry, and particularly relates to a method for simultaneously detecting 22 kinds of sugar, sugar alcohol and alcohols in fruit juice.

Background

The fruit juice is an important beverage in daily life, and contains components such as protein, amino acid, saccharide, sugar alcohol and the like. Among them, sugar compounds are the main source of energy required for people to sustain life activities. Sugar alcohols are substances formed by reducing the aldehyde group or ketone group of saccharides to hydroxyl group, are sweeteners mainly generated by reaction of corresponding sugars, do not cause elevation of blood sugar, and thus have an effect of preventing diabetes and obesity. Alcohols are compounds whose molecules contain a hydroxyl group bonded to a carbon on a side chain of a hydrocarbon group or a benzene ring, and many alcohols are beneficial to human health, but some alcohols have certain toxicity. The detection of the components of sugar and sugar alcohols is a difficult point in the field of analytical chemistry and a research hotspot in the field of analytical testing, and the sugar content of food must be labeled on a food label according to the regulations of national food safety standard prepackaged food nutrition label general rules in China at present.

The content of sugar, sugar alcohol and alcohol in the fruit juice directly influences the quality of the fruit juice. Currently, the main detection methods for saccharides, sugar alcohols, and alcohols include gas chromatography, liquid chromatography, enzyme electrode method, ion chromatography, and the like. The gas chromatography has the advantages of rapidness and sensitivity, but the pretreatment steps are complex, and the quantification is not accurate enough. The liquid chromatography has the characteristics of accuracy and good selectivity, but has low sensitivity. The enzyme electrode method generally detects only one kind of saccharide, and has good specificity but low detection efficiency. The ion chromatography has the advantages of simplicity, convenience, rapidness, sensitivity, accuracy and the like, and is a novel ideal method for simultaneously detecting multiple components.

Although research is currently conducted on methods for simultaneously detecting various sugars, sugar alcohols and alcohols in fruit juice, the methods can only search for a certain component (such as simple sugars or alcohols) or a small number of components detected simultaneously (only about 10 sugars and sugar alcohols are analyzed simultaneously) in a database at present, and cannot meet the increasing detection requirements.

Disclosure of Invention

Aiming at the defects of the prior art, the invention adopts the integral pulse ampere-ion chromatography, optimizes the pretreatment detection method, and establishes a method for simultaneously detecting 22 kinds of saccharides, sugar alcohols and alcohols in the fruit juice at one time by researching the influence factors of component separation.

In order to achieve the purpose, the invention discloses a method for simultaneously detecting 22 kinds of sugar, sugar alcohol and alcohols in fruit juice, which comprises the following detection steps;

step one, preparation of a mixed standard solution:

preparing a mixed standard stock solution from standard solutions of 2,3-butanediol, propylene glycol, methanol, glycerol, erythritol, xylitol, rhamnose, arabitol, sorbitol, trehalose, galactitol, mannitol, 2-deoxy-D-glucose, arabinose, melibiose, glucose, galactose, fructose, ribose, sucrose, raffinose and maltose according to the requirements;

step two, pretreatment of a sample to be detected:

taking 0.100 g of a fruit juice sample to be detected, adding about 80 mL of ultrapure water into a 100 mL beaker, uniformly mixing and standing for 10 min, adjusting the pH value of a diluent to 6.5-8.6 by using 0.10 mol/L sodium hydroxide solution, transferring all the diluent to a 100 mL volumetric flask, fixing the volume to the scale by using the ultrapure water, shaking up, standing for 15 min, taking 10.0 mL of solution, firstly passing through a 0.22 mu m filter membrane, then passing through a pre-activated IC-RP10 column, discarding the first 3 mL, collecting the later-stage clear liquid, and detecting.

Step three, ion chromatography conditions and multi-stage gradient leaching conditions

And (3) analyzing the column: CarboPac MA1 (4X 250 mm);

protection of the column: CarboPac MA1 (4X 50 mm);

a working electrode: gold;

reference electrode: an AgCl electrode;

mobile phase: a is 1000 mmol/L NaOH solution, B: ultrapure water;

flow rate: 0.40 mL/min;

column temperature: 30 ℃;

sample introduction amount: 10 mu L of the solution;

multi-stage gradient leaching conditions:

the multi-stage gradient elution procedure is as follows: when the time is 0.0-80.0 min, the concentration of the leacheate NaOH is 500.0 mmol/L; 80.0-85.0 min, and the concentration of the leacheate NaOH is 500.0-600.0 mmol/L; 85.0-105.0 min, wherein the concentration of the leacheate is 600.0 mmol/L; 105.0-110.0 min, and the concentration of the leacheate NaOH is 600.0-500.0 mmol/L; 110.0-120.0 min, and the concentration of the leacheate is 500.0 mmol/L; see table 1 for details.

TABLE 1 ion chromatography elution conditions

Step four, drawing a calibration curve:

detecting the mixed standard solution prepared in the step one by using an ion chromatograph according to the chromatographic analysis condition and the multi-stage gradient leaching condition given in the step three, drawing a calibration curve by taking the mass concentration of the component to be detected as a horizontal coordinate and the peak area of the component to be detected as a vertical coordinate, and quantifying by using an external standard method;

step five, detecting the sample solution:

detecting the clear liquid obtained in the step two by using an ion chromatograph according to the chromatographic analysis conditions and the multi-stage gradient leaching conditions given in the step three, and calculating a result;

step six, calculating a result:

and correcting the calculation result obtained in the step five by using the result obtained by mixing the standard solution in the step four, so as to calculate the content of each component in the measured fruit juice.

Preferably, the solutions are prepared using ultrapure water having a resistivity of 18.2 M.OMEGA.cm.

Has the advantages that:

1. the method for simultaneously detecting the sugar, the sugar alcohol and the alcohols in the fruit juice is always a technical difficulty in the field of analytical chemistry, and the method simultaneously detects 22 kinds of sugar, sugar alcohol and alcohols in the fruit juice at one time, solves the technical problem of low efficiency when various components are detected by adopting various standards, various instruments and various pretreatment methods at present, greatly improves the detection efficiency and reduces the detection cost.

2. The simultaneous separation and detection of 22 kinds of saccharide, sugar alcohol and alcohol components in fruit juice is a very difficult task. In order to improve the overall separation degree of the components, through experimental analysis and comparison, the method adopts an isocratic leaching method within the first 80 min, and adopts 600 mmol/L sodium hydroxide solution to strongly wash the chromatographic column after 85 min, so that interferents influencing the components to be detected are removed, and the detection accuracy can be greatly improved.

3. According to the invention, through multi-factor and multi-matrix investigation and analysis, experimental influence factors such as multi-level gradient elution conditions, initial elution concentration, chromatographic column temperature, pH value and the like are sequentially researched and analyzed, and the accuracy and the applicability of the method for simultaneously measuring multiple components are improved to the greatest extent.

4. Through in-depth research and analysis, the invention discovers the important influence of the pH value of the solution on the simultaneous detection of 22 components in the fruit juice, and the content of certain components is greatly fluctuated due to the change of the pH value. By adjusting the pH value of the solution to 6.5-8.6, the accuracy and precision of detection can be greatly improved.

5. The invention researches the important influence of the temperature of the chromatographic column on the detection, and the small change of the temperature of the chromatographic column can also cause component overlapping. At the column temperature of 30 ℃, the qualitative and quantitative requirements of 22 components can be met.

6. The detection method is simple, convenient and quick to operate and high in detection sensitivity, and can be used for on-machine detection through simple pretreatment operation.

7. The detection method does not use or generate solvents, reagents and byproducts which are harmful to human health and ecological environment, and accords with the concept of green analysis.

Drawings

FIG. 1 shows an ion chromatogram of a mixed standard solution of 22 kinds of sugars, sugar alcohols and alcohols.

FIG. 2 is an ion chromatogram of a mixed standard solution at different initial leacheate concentrations.

FIG. 3 is an ion chromatogram of a mixed standard solution at different column temperatures.

FIG. 4 is a graph showing the effect of pH on the detection of 6 components.

FIG. 5 is an ion chromatogram of 6 juice samples.

1, 2,3-Butanediol (2, 3-Butanediol); 2. propylene glycol (Propanediol); 3. methanol (Methanol); 4. glycerol (Glycerol); 5. erythritol (Erythritol); 6. xylitol (Xylitol); 7. rhamnose (L-rhamnose); 8. arabinitol (Arabinitol); 9. sorbitol (Sorbitol); 10. trehalose (trehalase); 11. galactitol (Galactitol); 12. mannitol (Mannitol); 2-Deoxy-D-glucose (2-Deoxy-D-glucose); 14. arabinose (arabinosine); 15. melibiose (Melibiose); 16. glucose (Glucose); 17. galactose (Galactose); 18. fructose (Fructose); 19. ribose (Ribose); 20. sucrose (Sucrose); 21. raffinose (Raffinose); 22. maltose (Maltose).

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

The first embodiment is as follows: method for simultaneously detecting 22 kinds of sugar, sugar alcohol and alcohols in fruit juice

1. Instruments and reagents

An ICS5000+ ion chromatography system equipped with an electrochemical detector and an autosampler (Thermo Scientific, USA); Milli-Q ultra pure water instruments (Millipore, USA); electronic balance (Mettler ML 802/02); water for experiment: ultrapure water (resistivity 18.2M Ω. cm); sugar, sugar alcohol, alcohol standards or standard reagents (purity > 98%); sodium hydroxide solution (50% w/w, Fisher Chemical); hydrochloric acid (guaranteed purity); IC-RP10 column (Agela Technologies).

2. Ion chromatography conditions

CarboPac MA1 (4X 250 mm) analytical column, CarboPac MA1 (4X 50 mm) guard column; a working electrode: gold (au); reference electrode: an AgCl electrode; mobile phase: NaOH leacheate (nitrogen blanket); flow rate: 0.40 mL/min; column temperature: 30 ℃; sample introduction amount: 10 μ L. Initial leaching concentration: 500 mmol/L NaOH solution.

3. Multi-stage gradient leaching conditions:

the multi-stage gradient elution procedure is as follows: when the time is 0.0-80.0 min, the concentration of the leacheate NaOH is 500.0 mmol/L; 80.0-85.0 min, and the concentration of the leacheate NaOH is 500.0-600.0 mmol/L; 85.0-105.0 min, wherein the concentration of the leacheate is 600.0 mmol/L; 105.0-110.0 min, and the concentration of the leacheate NaOH is 600.0-500.0 mmol/L; 110.0-120.0 min, and the concentration of the leacheate is 500.0 mmol/L.

4. Preparation of mixed standard solution:

preparing a mixed standard solution with a certain concentration according to a standard product or standard solution of 2,3-butanediol, propylene glycol, methanol, glycerol, erythritol, xylitol, rhamnose, arabitol, sorbitol, trehalose, galactitol, mannitol, 2-deoxy-D-glucose, arabinose, melibiose, glucose, galactose, fructose, ribose, sucrose, raffinose and maltose, and adjusting the pH value of the solution to 6.5-8.6 in the process of preparing the mixed standard solution.

5. Pretreatment of a sample to be detected:

taking 0.100 g of a fruit juice sample to be detected, adding about 80 mL of ultrapure water into a 100 mL beaker, uniformly mixing and standing for 10 min, adjusting the pH value of a diluent to 6.5-8.6 by using 0.10 mol/L sodium hydroxide solution, transferring all the diluent to a 100 mL volumetric flask, fixing the volume to the scale by using the ultrapure water, shaking up, standing for 15 min, taking 10.0 mL of solution, firstly passing through a 0.22 mu m filter membrane, then passing through a pre-activated IC-RP10 column, discarding the first 3 mL, collecting the later-stage clear liquid, and detecting.

The 22 kinds of sugars, sugar alcohols and alcohols in the mixed standard solution were detected under the conditions of the above experimental analysis, and the results of the detection are shown in FIG. 1.

Example two: effect of flow velocity on detection

According to the conditions of the experimental analysis in the first embodiment, the separation of the components of the mixed standard solution was tested under the conditions of the flow rates of 0.30 mL/min, 0.40 mL/min, 0.50 mL/min and 0.60 mL/min of the leacheate, and the relationship between the flow rate of the leacheate and the system pressure is shown in Table 2.

TABLE 2 relationship of flow rate of rinsing liquid to system pressure

From Table 2, it can be seen that the system pressure was 885 psi at 0.30 mL/min for the eluent flow rate, because the flow rate was lower, the pressure was lower, the peak width increased, the peak sensitivity decreased, and the overall resolution was not high. At a flow rate of 0.50 mL/min, the system pressure reached 1430 psi, and although the component sensitivity was improved, the degree of separation between individual components was not ideal. At a flow rate of 0.60 mL/min, the system pressure reaches 1705 psi, the system pressure is higher, approaching the upper recommended pressure limit of the column of 2000 psi, the overall analysis time of the components is shortened, but the overall separation of the components is reduced, and the higher pressure will affect the service life of the column to some extent. The initial pressure of 1155 psi at the flow rate of 0.40 mL/min, the pressure is moderate, and the sensitivity and the separation degree of the components can meet the detection requirements. Therefore, the present invention chooses to perform the experiment at a flow rate of 0.40 mL/min, in view of system stability, resolution, and sensitivity.

Example three: effect of Multi-stage gradient elution conditions on detection

According to the conditions of the experimental analysis in the first example, the separation of the components of the mixed standard solution under the conditions of 420, 450, 480, 500, 520 and 550 mmol/L of the initial leacheate is tested sequentially under the condition that other conditions are not changed, and the influence of the initial concentration on the separation degree of the three components 20, 21 and 22 is small, so that the influence of the initial concentration on the first 19 components is mainly discussed, and the separation of the components of the mixed standard solution is shown in FIG. 2.

As can be seen from FIG. 2, when the initial elution concentrations were 420 and 450 mmol/L, respectively, neither of components 7 and 8 nor of components 10 and 11 was separated; when the initial leaching concentration is 480 mmol/L, the separation degrees of the components 10 and 11 are not high; when the initial leaching concentrations are 520 mmol/L and 550 mmol/L respectively, the components 14 and 15 are not completely separated; the overall resolution and sensitivity of these 19 components was ideal at an initial elution concentration of 500 mmol/L. Therefore, the initial leaching concentration is 500 mmol/L for experimental detection.

Example four: effect of column temperature on detection

According to the conditions of the experimental analysis in the first example, the separation effect of 22 kinds of saccharides, sugar alcohols and alcohols was successively tested under the conditions of 25 ℃, 27.5 ℃, 30 ℃, 32.5 ℃ and 35 ℃ of column temperature without changing other conditions, and the test results are shown in FIG. 3.

As can be seen from FIG. 3, the lower column temperature was found at 25 ℃ and 27.5 ℃ and the separation of most of the components was good, but the components 10 trehalose and 11 galactitol were completely overlapped and no separation was achieved. When the temperature of the chromatographic column is 32.5 ℃, the ion exchange rate is increased, the column efficiency is improved, the analysis time is shortened, particularly, the retention time of the components 20, 21 and 22 is shortened, but the column selectivity is reduced, and the component 14 arabinose and the component 15 melibiose are almost overlapped together, so that the quantitative accuracy cannot be ensured. At 35 c column temperature, a total of 3 pairs of fractions co-eluted, fractions 7 and 8, fractions 9 and 10, and fractions 14 and 15, respectively, were present, and it was seen that the degree of separation between fractions decreased significantly with increasing temperature. In addition, it was found that the sensitivity of fraction 18 fructose and fraction 22 maltose became smaller with increasing temperature and both were detected at column temperature of 35 ℃, from which it was seen that the column temperature had a similarly large effect on the sensitivity of the fractions. At the column temperature of 30 ℃, the analysis rate is moderate, the separation degree is good, and the overall separation effect of 22 components is good, so that the temperature has obvious influence on the simultaneous detection of the 22 components, and the experimental analysis is carried out at the column temperature of 30 ℃ in the invention from the aspects of improving the separation degree, sensitivity and selectivity of the method.

Example five: effect of pH on detection

According to the conditions of the experimental analysis in the first embodiment, under the condition that other conditions are not changed, mixed standard solutions with different pH values (2.0-12.0) and the same theoretical concentration are sequentially prepared for the on-machine detection, and the experimental result shows that the detected content of 6 components of glucose, glycerol, galactose, ribose, melibiose and maltose is greatly influenced by the pH value of the solution, the other components are slightly influenced by the pH value, and the influence of 6 components of glucose, glycerol, galactose, ribose, melibiose and maltose on the detection by different pH values is shown in fig. 4.

As can be seen from FIG. 4, when the pH is less than 8.6, the detected content of 5 sugars, glucose, galactose, ribose, melibiose and maltose is almost unchanged, while when the pH is greater than 10.5, the glucose content is greatly increased, and the detected content of the other 4 sugars is decreased, because disaccharides or polysaccharides, such as maltose and melibiose, can be hydrolyzed under alkaline conditions to generate a certain amount of glucose. When the pH value of the glycerol is less than 6.5 and the pH value of the glycerol is more than 8.6, the detection content is increased to a certain extent, because the glycerol is a trihydric alcohol and is greatly influenced by the acidity and alkalinity, and under the condition of strong acid or strong alkali, the ionization degree of the glycerol in the solution is higher, and the detection content is higher. The invention comprehensively considers the influence factors of physicochemical characteristics, dissociation degree, sensitivity and the like of 22 components, and the pH value is selected to be 6.5-8.6 for analysis and detection.

Example six: linear range and detection limit

Mixed standard solutions of different concentrations were prepared and a calibration curve fit was performed using the chromatographic conditions in example one. The detection limit of the component to be measured was calculated from the chromatographic peak signal-to-noise ratio (S/N = 3), and detection and linear fitting were performed for 8 concentration levels (0.10, 0.20, 0.40, 1.0, 2.0, 4.0, 10.0, 20.0 mg/L) of the mixed standard solution in the concentration range of 0.10 mg/L to 20.0 mg/L, and the results are shown in table 3.

Table 3 linear range, linear equation, correlation coefficient and detection limit of detection components (S/N = 3)

Y: peak area (nc. min), X: mass concentration (mg/L)

As can be seen from Table 3, the linear correlation coefficients of the 22 components are all greater than 0.999, which indicates that the components are detected simultaneously under the experimental conditions with good linearity. The detection limit of other 21 components except methanol is between 0.0059 and 0.2059 mg/L.

Example seven: recovery and precision

3 samples of pear juice, peach juice and mixed juice are respectively selected, mixed standard solutions with concentration levels of 0.50 mg/L, 1.00 mg/L and 5.00 mg/L are sequentially added into the 3 samples, each concentration level is subjected to 6 times of parallel determination experiments to verify the recovery rate and the precision of different juice matrix detection methods, and the recovery rate is calculated according to the matrix concentration, the added concentration and the detection concentration after addition. Table 4 lists the three concentration levels, the average recovery of six tests and RSD data.

TABLE 4 recovery and precision (RSD) of assay components: (n=6）

As can be seen from Table 4, except that the recovery rates for 2,3-butanediol and methanol were not high, at the 0.50 mg/L addition level, 71.71% and 73.34%, respectively; at the addition concentration level of 1.00 mg/L, the recovery rate of only 2,3-butanediol is lower than 80 percent, because the two alcohols have strong volatility and are lost in the pretreatment process; the recovery rate of other 20 components is 81.42-106.17%, all recovery rate data meet the technical requirements of food physicochemical inspection (the detection content is less than 0.10 mg/L, and the recovery rate is 60-120%), which fully indicates that the recovery rates of 22 saccharides, sugar alcohols and alcohols are good. At three concentration levels, the RSD of 22 components is in the range of 1.03-11.12%. In general, the recovery rate data results of three matrixes and six parallel detections meet the physicochemical detection requirements of foods, and the detection method is high in accuracy and good in precision.

Example eight: detection of actual samples

The content of 22 kinds of saccharides, sugar alcohols and alcohols in the actual sample was analyzed by extracting 6 kinds of common fruit juice beverages (apple juice, grape juice, pear juice, mango juice, peach juice and mixed juice) and performing ion chromatography conditions and pretreatment steps in the first embodiment, table 5 shows the results of the data of the detection components, and fig. 5 shows the ion chromatogram of the detection of the actual sample.

TABLE 5 detection results (mg/L) of fruit juice samples

"-": not detected out

Comparing 6 fruit juice chromatograms, wherein 10 components are detected from 6 fruit juices, the main saccharides contained in the fruit juice are glucose, fructose and sucrose, the glucose content in the grape juice is high, and a small amount of arabinose is detected; the main sugar alcohols contained in the fruit juice are glycerol and sorbitol, and a small amount of xylitol and mannitol are detected in the apple juice; of particular note is the detection of the toxic 2,3-butanediol in grape juice, indicating that quality control of this batch of juice is problematic during production or packaging. From the aspect of detecting the component quantity, the apple juice, the peach juice and the mixed fruit juice are detected in sequence, the mixed fruit juice belongs to a novel nutritional dietary beverage, various kinds of saccharide components are contained, the component content is uniformly distributed, and the balanced nutrition of a human body is facilitated by frequent drinking.

According to the invention, through deep research on various experimental influence factors such as initial leaching concentration, flow rate, column temperature, solution pH value and the like, chromatographic separation conditions for simultaneously detecting 22 sugars, sugar alcohols and alcohols in the fruit juice are explored, and an analysis method for simultaneously detecting 22 sugars, sugar alcohols and alcohols in the fruit juice by using an integral pulse ampere-ion chromatography is established. The method is simple, rapid, sensitive and accurate, and is completely suitable for rapid analysis of 22 kinds of sugar, sugar alcohol and alcohol in the fruit juice.

The present invention is not limited to the above embodiments, and variations and advantages that can be realized by those skilled in the art are included in the present invention without departing from the spirit and scope of the inventive concept, and the scope of the present invention is defined by the appended claims.

Claims (2)

1. A method for simultaneously detecting 22 kinds of sugar, sugar alcohol and alcohol in fruit juice is characterized by comprising the following steps:

step one, preparation of a mixed standard solution:

preparing a mixed standard solution from standard solutions of 2,3-butanediol, propylene glycol, methanol, glycerol, erythritol, xylitol, rhamnose, arabitol, sorbitol, trehalose, galactitol, mannitol, 2-deoxy-D-glucose, arabinose, melibiose, glucose, galactose, fructose, ribose, sucrose, raffinose and maltose according to the requirements;

step two, pretreatment of a sample to be detected:

taking 0.100 g of a fruit juice sample to be detected into a 100 mL beaker, adding about 80 mL of ultrapure water, uniformly mixing and standing for 10 min, adjusting the pH value of a diluent to 6.5-8.6 by adopting 0.10 mol/L sodium hydroxide solution, transferring all the diluent into a 100 mL volumetric flask, fixing the volume to a scale by adopting the ultrapure water, shaking up, standing for 15 min, taking 10.0 mL of solution, firstly passing through a 0.22 mu m filter membrane, then passing through a pre-activated IC-RP10 column, discarding the front 3 mL, collecting the later-stage clear liquid, and detecting;

step three, ion chromatography conditions and multi-stage gradient leaching conditions

And (3) analyzing the column: CarboPac MA 14X 250 mm;

protection of the column: CarboPac MA 14X 50 mm;

a working electrode: gold;

reference electrode: an AgCl electrode;

mobile phase: a is 1000 mmol/L NaOH solution, B: ultrapure water;

flow rate: 0.40 mL/min;

column temperature: 30 ℃;

sample introduction amount: 10 mu L of the solution;

multi-stage gradient leaching conditions:

the multi-stage gradient elution procedure is as follows: when the time is 0.0-80.0 min, the concentration of the leacheate NaOH is 500.0 mmol/L; 80.0-85.0 min, and the concentration of the leacheate NaOH is 500.0-600.0 mmol/L; 85.0-105.0 min, wherein the concentration of the leacheate is 600.0 mmol/L; 105.0-110.0 min, and the concentration of the leacheate NaOH is 600.0-500.0 mmol/L; 110.0-120.0 min, and the concentration of the leacheate is 500.0 mmol/L;

step four, drawing a calibration curve:

detecting the mixed standard solution prepared in the step one by using an ion chromatograph according to the chromatographic analysis condition and the multi-stage gradient leaching condition given in the step three, drawing a calibration curve by taking the mass concentration of the component to be detected as a horizontal coordinate and the peak area of the component to be detected as a vertical coordinate, and quantifying by using an external standard method;

step five, detecting the sample solution:

detecting the clear liquid obtained in the step two by using an ion chromatograph according to the chromatographic analysis conditions and the multi-stage gradient leaching conditions given in the step three, and calculating a result;

step six, calculating a result:

and correcting the calculation result obtained in the step five by using the result obtained by mixing the standard solution in the step four, so as to calculate the content of each component in the measured fruit juice.

2. The method according to claim 1, wherein the solutions are prepared using ultrapure water having a resistivity of 18.2M Ω -cm.

Images