CN101949877A - Method for measuring edible oleic acid value based on conductivity - Google Patents
Method for measuring edible oleic acid value based on conductivity Download PDFInfo
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Abstract
The invention discloses a method for measuring an edible oleic acid value based on conductivity, which utilizes a conductivity meter as a detection tool. The method comprises the following steps: when in measurement, fully mixing alkali liquor having a certain low concentration with an oil sample according to a certain mixing proportion; standing for delamination; and then measuring the conductivity of the alkali liquor layer, and predicting the edible oleic acid value through the change of the conductivity of the alkali liquor layer and by using a model. The measuring step is divided into modeling, model verifying, blind sample verifying, model predicting application and the like. The method has simple application without poisonous organic solvents. An oil-alkali mixing proportion can be regulated according to the practical detection requirements so as to meet different acid value measuring scopes and different precision requirements. The method is a novel method for measuring the edible oleic acid value.
Description
Technical field
The invention belongs to the chemical analysis detection range, be specifically related to a kind of assay method of the edible oil acid number based on conductivity.
Background technology
Acid number is an edible oil hygienic standard and in processing, an important indicator of mass change in the storage, also is the measuring of free content of fatty acid in the evaluation edible oil.
At present, the national standard method of China's edible oil acid value measuring is the acid base neutralization titration method, comprises GB/T 14489.3-1993, GB/T5009.37-2003 and GB/T5530-2005.Titrimetry is with behind the neutral ether-ethanol mixed solvent dissolving oil sample, uses the free fatty acid in the potassium hydroxide standard solution titration grease again, calculates acid value of oil and fat according to the amount that consumes potassium hydroxide and oil quality.
General the most frequently used animal and plant fat acid value measuring method is an acid base titration, but this method has following limitation.
1. by the indicator change color, judge that the reaction end error is bigger, in especially dark in color or the grease that emulsification is muddy, the endpoint error is bigger;
2. the oil sample consumption is big, the titration length that expends time in;
3. detect when hanging down the acid number grease, its sensitivity and degree of accuracy are lower;
4. the required chemical reagent of titrimetry is many, and the solution process for preparation is loaded down with trivial details, is difficult to satisfy the demand of field quick detection, and organic solvent easily causes the pollution of environment;
5. the potassium hydroxide standard solution more easily absorbs carbon dioxide in air, and the carbonate of generation can influence the concentration of potassium hydroxide standard solution and cause the error of measurement result.
Chinese scholars is updated the assay method of edible oil acid number.Except that titration method commonly used is improved, methods such as near infrared spectroscopy, chromatography, colourimetry, test paper method, potentiometric titration, voltammetry have been proposed also.Improvement on the titration method comprises adopts thymol blue to replace phenolphthalein indicator, changes ether into sherwood oil, reduces the mixed solvent consumption, methods such as saturated aqueous common salt breakdown of emulsion.Though the near infrared determination method has plurality of advantages, instrument costs an arm and a leg, and needs the utilization chemometrics method to set up the spectral signature of standard model and the mathematical model between the mensuration component content.Chromatography needs standard items to compare, and this method is more suitable for measuring the content and the fatty acid component of single fatty acid in the sample.Colourimetry is simple, and finding speed is fast, and precision is also better, does not need the instrument of complex and expensive, but the relative error of its measurement result is bigger.The test paper method poor stability, it is not high to measure precision, does not reach the GB requirement.Potential Titration Analysis speed is fast, and personal error is little, but this method is higher to the dependence of instrument self precision, needs a large amount of oil samples to do loaded down with trivial details titration and calibration procedure.Though voltammetry is easy, only need small amount of sample just can realize accurate measurement, need to select a kind ofly also need use flowing injecting analysis technology to acidity sensitivity and the adjuvant that is easy to measure, mensuration person's technical ability is had relatively high expectations.
Summary of the invention
Defective or deficiency at above-mentioned prior art existence, the objective of the invention is to, a kind of assay method of the edible oil acid number based on conductivity is provided, this method utilizes conductivity meter as testing tool, the acid number of edible oil can be accurately measured, the error that occurs in the titration experiments process can be significantly reduced.Method itself is not subjected to the influence of exhausted changes in environmental conditions, during practical application operator's technical ability is not had specific (special) requirements, and simple and easy to do, non-volatility, safety non-toxic can not cause environmental pollution.Can require to adjust oily alkali blending ratio to satisfy the requirement of different acid value measuring scopes and precision according to actual detected.
In order to realize above-mentioned task, the technical scheme that the present invention takes is:
A kind of method of the mensuration edible oil acid number based on conductivity, it is characterized in that, this method utilizes conductivity meter as testing tool, and by setting up the acid number of acid number and the model determination edible oil that mixes potassium hydroxide solution conductivity variations value relation, concrete operations comprise the following steps:
1) modelling:
A, compound concentration are the potassium hydroxide solution of 0.04～0.06mol/L and measure its conductivity;
B, 5～10 of the edible oil sample of getting known acid number, the weight of each edible oil sample is 5.000g, places the conical flask back stand-by respectively, if edible oil sample is a solid fat, then heating is transformed into liquid;
C, according to measuring acid number scope and accuracy requirement, in each edible oil sample, add potassium hydroxide solution, its addition is: the edible oil sample quality: the potassium hydroxide solution volume is=1:3～1:10,3～5s then vibrates, leave standstill 3～5min, directly the electrode with conductivity meter inserts in the alkali lye layer, measures alkali lye layer conductivity, calculates its conductivity variations value;
D, set up the funtcional relationship of edible oil acid number and conductivity variations value.
2) modelling verification:
It is known and be different from the edible oil of modeling oil sample kind to get acid number, dispose 3～5 oil samples, measure alkali lye layer conductivity variations value respectively by modeling method (control same oil alkali blending ratio), predict the oil sample acid number according to institute's established model, and compare with actual acid number.The prediction of checking oil sample acid number and measured value relative deviation≤10%, predicted value and actual value related coefficient 〉=0.95.
3) blind sample checking: get the blind sample of some, by the alkali lye layer conductivity variations value of modeling method (control same oil alkali blending ratio) mensuration oil sample, by the blind sample acid number of model prediction.Measure blind sample acid number with GB/T 14489.3-1993 National Standard Method, predicted value and measured value relative deviation≤10% in addition.
4) model is used:
Set by step 1) model of setting up, get oil sample 5.000g to be measured, set by step 1) C step control same oil alkali blending ratio, vibration 3～5s, leave standstill 3～5min, directly the electrode with conductivity meter inserts in the alkali lye layer, measures alkali lye layer conductivity variations value, model prediction oil sample acid number is set up in utilization, obtains the acid number of this edible oil.
Method of the present invention is easy and simple to handle, need not to use organic reagent, and the result is accurate, favorable reproducibility, provides a kind of new method for measuring the edible oil acid number.
Use the present invention and measure the edible oil acid number, the technique effect that brings is as follows:
(1) measures based on conductivity meter, can significantly reduce the test error in the titration process.
(2) method requires simply, operator's technical ability is not had specific (special) requirements, easy and simple to handle the instrument of measuring.The reagent use amount is little, non-volatility, safety non-toxic can not cause environmental pollution.
(3) method itself is not subjected to the influence of environmental change.Can require to adjust oily alkali blending ratio to satisfy the requirement of different acid value measuring scopes and precision according to actual detected.
Description of drawings
Fig. 1 is the influence of different K OH solution concentration to the conductivity value changing value;
Fig. 2 is the influences of different time of repose to alkali lye layer conductivity variations value;
Fig. 3 measures the influence of temperature to alkali lye layer conductivity variations value;
Fig. 4 is variety classes grease conductivity variations value and acid number regression relation figure, wherein, Fig. 4 (a) expression rapeseed oil conductivity variations value and acid number regression relation, Fig. 4 (b) expression corn oil, peanut oil, sunflower oil, soybean oil conductivity variations value and acid number regression relation;
Fig. 5 is the influences of different oily alkali mixing ratios to conductivity variations value and acid number regression relation; Wherein, Fig. 5 (a) is that oily alkali blending ratio (w/v) is 1:2; Fig. 5 (b) is that oily alkali blending ratio (w/v) is 1:3; Fig. 5 (c) is that oily alkali blending ratio (w/v) is 1:4; Fig. 5 (d) is that oily alkali blending ratio (w/v) is 1:5; Fig. 5 (e) is that oily alkali blending ratio (w/v) is 1:10.
Fig. 6 is the acid number model;
Fig. 7 is modelling verification;
The present invention is described in further detail below in conjunction with embodiment that the inventor provides.
Embodiment
Mentality of designing of the present invention is, utilizes conductivity meter as testing tool, and conductivity is the ability of object conduction current.The measuring principle of conductance instrument is with two parallel pole plates, is put in the detected solution, adds certain electromotive force (being generally sine voltage) at the two ends of pole plate, the electric current that flows through between measuring pad then.In electrolytical solution, charged ion produces and moves and the transmission electronics under electric field effects, has electric action.The power of its conductive capability is called conductivity.It is the inverse of resistance that electricity is led, and measures the method that electricity is led size, and available two electrodes insert in the solution, to measure the resistance of two interpolars.According to Ohm law, temperature one timing, this resistance is directly proportional with the spacing of electrode, with the sectional area inverse ratio of electrode.
In order to determine conductivity meter mensuration edible oil acid number condition, the applicant verifies the conductance measurement condition.The applicant is a raw material with rapeseed oil, peanut oil, sunflower oil, cause that by measuring different acid number oil samples alkali lye conductivity variations value and acid number compare analysis, choosing concentration of potassium hydroxide, time of repose, fat type, oily alkali blending ratio (w/v) and temperature is factor, determine suitable condition determination, randomly drawing one-level rapeseed oil, level Four rapeseed oil, squeezing peanut oil, the edible four kinds of edible oils of wet goods of enzymolysis then, to make the acid number scope be that 0～10KOHmg/g tests, and sets up acid number and mix the model that potassium hydroxide solution conductivity variations value concerns.
After the modelling, randomly draw 10 different acid number oil samples, adopt national standard method to measure its acid number earlier, adopt conductance measurement then and calculate its acid number, carry out modelling verification.Measure testing sample alkali lye layer conductivity variations, can calculate acid number according to model.Checking oil sample acid number predicted value and measured value relative deviation≤10%, and related coefficient 〉=0.95 of the equation of linear regression of predicted value and actual value foundation.
Modelling verification: get the blind sample of some, measure alkali lye layer conductivity variations value and predict acid number by modeling method (control same oil alkali blending ratio).Measure its acid number with National Standard Method, predicted value and measured value relative deviation≤10%.
Blind sample checking: can carry out the acid value measuring (application) of oil sample, measure oil sample alkali lye layer conductivity variations value to be measured respectively, utilize and set up its acid number of model prediction by modeling method (control same oil alkali blending ratio).
Concrete experiment comprises:
(1) raw material
Rapeseed oil: commercially available; Peanut oil: commercially available; Sunflower oil: commercially available; Edible oil in bulk: commercially available; Waste oil and frying oil: be collected in Yangling District restaurant, Shaanxi Province.
(2) oil sample pre-service
Compound concentration is 0.04mol/LKOH solution and measures its conductivity.Get edible oil sample 5g, be accurate to 0.001g.Oil sample to be measured is placed the 50mL/150mL conical flask, add KOH solution 25mL～100mL according to measuring acid number scope and accuracy requirement, vibration 3～5s leaves standstill 3～5min.
(3) conductance measurement
Corrected conductivity rate instrument, and the conductivity of the initial KOH solution of survey record (needing to proofread and correct by temperature correction facotor) are treated that KOH solution and oil sample fully mix the conductivity of back, layering, mensuration alkali lye layer, and are calculated its conductivity variations value.
(4) acid value measuring
The acid value of oil and fat assay method is with reference to GB GB/T 14489.3-1993.
(5) testing conditions is determined
1) influence of potassium hydroxide solution concentration
Getting concentration in low strength range respectively is that 0.01mol/L～0.06mol/L potassium hydroxide solution mixes back mensuration alkali lye layer conductivity variations value with same oil sample, and its conductivity value result of variations is seen Fig. 1.
As seen from Figure 1, the KOH solution concentration is little to the conductivity variations value influence that extracts same oil sample alkali lye layer, so can require to select different concentration of lye according to different mensuration.
2) influence of time of repose
Alkali lye and two kinds of oil samples are fully mixed, leave standstill the conductivity of 5min～35min every 5min mensuration alkali lye layer solution, the conductivity value result of variations is seen Fig. 2.
As shown in Figure 2, the conductivity variations value and the time of repose of different oil sample alkali lye layers do not have obvious relation, and time of repose is to the not influence of alkali lye layer conductivity variations pH-value determination pH.
3) Temperature Influence
Temperature is one of key factor that influences conductivity, measures the variation of oil sample alkali lye layer conductivity under 15～35 ℃ of different temperatures, and it the results are shown in Figure 3.
As seen from Figure 3, proofread and correct by conductivity temperature compensation between 15～35 ℃, it is little to the conductivity variations value influence of alkali lye layer to measure temperature, can consider temperature effect during mensuration.
4) influence of fat type
Various Edible fatty acid constituent difference, each components contents is also different, chosen rapeseed oil, corn oil, peanut oil, sunflower oil, the several frequently seen edible oil of soybean wet goods respectively and tested, and the conductivity variations value pair has been carried out regretional analysis with the oil sample acid number.It the results are shown in Figure 4.
As shown in Figure 4, slope and intercept are non-very approaching in the different fat type regression equations with other of rapeseed oil regression equation.This shows that fat type does not make significant difference to measurement result.
5) influence of oily alkali blending ratio
Oil alkali blending ratio (w/v) (hereinafter to be referred as oily alkali mixing ratio) has determined acid number scope and measuring accuracy that the model of setting up is measured, choose 1:2,1:3,1:4,1:5,1:10 tests, the regression relation of conductivity variations value and oil sample acid number is seen Fig. 5.
As shown in Figure 5, different oily alkali mixing ratios are to the recurrence coefficient of determination (R of conductivity variations value and acid number
2) all greater than 0.99, illustrate that different oily alkali mixing ratio institute established model all has measurable meaning.During mensuration, can select different oily alkali mixing ratios according to the acid number scope.From the slope of regression equation, along with the increase of oily alkali mixing ratio, its measurement range increases, and its accuracy of detection descends thereupon on the contrary.
(6) modelling
More than test shows that other factors does not all make significant difference to experimental result outside the oil removing alkali mixing ratio.Randomly draw one-level rapeseed oil, level Four rapeseed oil, squeezing peanut oil, four kinds of edible oils of enzymolysis edible oil mix acid number 0～10KOHmg/g scope and test, and set up the relation of acid number and conductivity variations value.Setting up Model Selection oil alkali mixing ratio is 1:10 (w/v), and the relation of acid number and conductivity variations value as shown in Figure 6.
As seen from Figure 6, alkali lye layer conductivity variations value and acid number linear relationship are good, R
2Be 0.9984 to approach 1, institute's established model is feasible.
(7) modelling verification
After the modelling, randomly draw the oil sample of 13 different acid numbers, adopt national standard method to measure its acid number earlier, adopt electrical conductivity method to measure and the calculating acid number then, carry out modelling verification, it the results are shown in Figure 7.
As seen from Figure 7, the regression relation slope of the measured value of acid number and predicted value is 0.949 to approach 1, R
2Approach 1, illustrate that measured value and predicted value are very approaching, it is feasible that electrical conductivity method is measured the edible oil acid number.
(8) the blind sample checking of model
Randomly draw 10 oil samples from market, adopt national standard method to measure acid number earlier, adopt conductance measurement alkali lye layer conductivity variations then and calculate its acid number, carry out blind sample checking, it the results are shown in Table 1.
Table 1: blind sample checking and relative deviation
As can be seen from Table 1,10 blind all product by the model prediction acid number with the relative error of national standard method measurement result all less than 10%, meet national standard to the acid value measuring relevant regulations, illustrate that it is complete feasible that electrical conductivity method is measured the acid number of edible oil.
The present invention utilizes conductivity meter to measure acid value of oil and fat, by setting up the correlation model of acid number and alkali lye layer conductivity variations value, according to alkali lye layer conductivity variations value prediction edible oil acid number.
It below is the specific embodiment that the inventor provides, need to prove that following example has provided the mensuration of the grease of high, medium and low acid number respectively, the invention is not restricted to these embodiment, according to method of the present invention, all can realize the mensuration of acid number to any edible oil.
Embodiment 1: rapeseed oil (interpolation vitamin E) acid value measuring
1) rapeseed oil (interpolation vitamin E) is commercially available, uniform sampling.
2) modelling: compound concentration is about the KOH solution of 0.06mol/L and measures its conductivity.Get the liquid edible oil samples 5g of 10 known acid numbers, be accurate to 0.001g.Oil sample to be measured is placed the 50mL conical flask, and controlling oily alkali blending ratio is 1:3 (w/v), promptly adds KOH solution 15mL, and vibration 5s leaves standstill 3min, directly electrode is passed oil reservoir and inserts the alkali lye layer, measures the extract conductivity variations.Set up the funtcional relationship of edible oil acid number and conductivity variations value: the acid number of y=0.0007x+0.1096(y-testing sample, the changing value of x-testing sample KOH water conductivity, down together).
3) modelling verification: it is known and be different from the edible oil of modeling oil sample kind to get acid number, dispose 10 oil samples, its acid number evenly covers the modeling curve, measure oil sample conductivity variations value respectively by modeling method (control same oil alkali mixing ratio), according to its acid number of pattern function Relationship Prediction, and with the comparison of actual acid number.
4) blind sample checking: get the blind sample of some, measure oil sample conductivity variations value and predict acid number, measure its actual acid number with National Standard Method by modeling method (control same oil alkali mixing ratio).
5) rapeseed oil acid value measuring: measure rapeseed oil alkali lye layer conductivity variations value by modeling method (control same oil alkali mixing ratio).Utilize model y=0.0007x+0.1096 to predict its acid number, and measure with National Standard Method, every kind of method is all done three replicate determinations, and the measurement result comparative analysis sees Table 2.
Table 2: rapeseed oil acid value measuring and relative deviation are relatively
As can be seen from Table 2, the mean value that method of the present invention is measured edible oil acid number and GB determination of acid-basetitration is respectively 0.52KOHmg/g and 0.51KOHmg/g, and two kinds of method measurement result relative deviations are 0.95%, do not have the significance difference opposite sex.From using on the reagent type, use the ethanol ether mixed solution to have strong volatility and certain toxicity in the national standard method.Use the equal non-volatility of reagent based on conductivity method, safety non-toxic can not cause environmental pollution.From the operator is required, no matter the National Standard Method acid base titration all requires the reviewer to have certain operating experience from titration process or on endpoint.And conductivity method mensuration acid number does not have specific (special) requirements to operator's technical ability, and is simple and easy to do.This shows that it is fully feasible that conductivity method is measured the rapeseed oil acid number, environmental pollution and little to the harm of operating personnel's health.
Embodiment 2: market frying oil acid value measuring
1) frying oil is that uniform sampling after the filtration treatment is gathered in Yangling District restaurant, Shaanxi.
2) modelling: compound concentration is the KOH solution of 0.05mol/L and measures its conductivity.Get the liquid edible oil samples 5g of 10 known acid numbers, be accurate to 0.001g.Oil sample to be measured is placed the 50mL conical flask, and controlling oily alkali blending ratio is 1:5 (w/v), promptly adds KOH solution 25mL, and vibration 5s leaves standstill 3min, directly electrode is passed oil reservoir and inserts the alkali lye layer, measures alkali lye layer conductivity variations.Set up the funtcional relationship of edible oil acid number and conductivity variations value: y=0.001x+0.017.
3) modelling verification: it is known and be different from the edible oil of modeling oil sample kind to get acid number, dispose 10 oil samples, its acid number evenly covers the modeling curve, measure oil sample conductivity variations value respectively by modeling method (control same oil alkali mixing ratio), according to its acid number of pattern function Relationship Prediction, and compare with measured value.
4) blind sample checking: get the blind sample of some, measure oil sample conductivity variations value and predict acid number, measure its actual acid number with National Standard Method by modeling method (control same oil alkali mixing ratio).
5) market frying oil acid value measuring: measure market frying oil conductivity variations value by modeling method (control same oil alkali mixing ratio).Utilize " y=0.001x+0.017 " to calculate its acid number.And measure with National Standard Method, every kind of method is all done three replicate determinations, and the measurement result comparative analysis sees Table 3.
Table 3: market frying oil acid value measuring and relative deviation are relatively
As can be seen from Table 3, the mean value that method of the present invention is measured edible oil acid number and GB determination of acid-basetitration is respectively 1.26KOHmg/g and 1.26KOHmg/g, and two kinds of method measurement result relative deviations are 0.57%, do not have the significance difference opposite sex.From using on the reagent type, use the ethanol ether mixed solution to have strong volatility and certain toxicity in the National Standard Method.Use the equal non-volatility of reagent based on electrical conductivity method, safety non-toxic can not cause environmental pollution yet.From the operator is required, no matter the National Standard Method acid base titration all requires the reviewer to have certain operating experience from titration process or on endpoint.And measure acid number operator's technical ability there is not specific (special) requirements based on conductivity method, simple and easy to do.This shows, be fully feasible based on the acid number of conductance measurement market frying oil, environmental pollution and little to the harm of operating personnel's health.
Embodiment 3: market chafing dish oleic acid pH-value determination pH
1) chafing dish oil is that gather in Yangling District chafing dish restaurant, Shaanxi Province, the back uniform sampling of filtering, decolour.
2) modelling: compound concentration is the KOH solution of 0.04mol/L and measures its conductivity.Get the liquid edible oil samples 5g of 10 known acid numbers, be accurate to 0.001g, solid need be heated into liquid.Oil sample to be measured is placed the 50mL conical flask, and controlling oily alkali blending ratio is 1:10 (w/v), promptly adds KOH solution 50mL, and vibration 5s leaves standstill 3min, directly electrode is passed oil reservoir and inserts water, measures the extract conductivity variations.Set up the funtcional relationship of edible oil acid number and conductivity variations value: y=0.0024x-0.01571.
3) modelling verification: it is known and be different from the edible oil of modeling oil sample purposes/kind to get acid number, dispose 12 oil samples, its acid number evenly covers the modeling curve, measure oil sample conductivity variations value respectively by modeling method (control same oil alkali mixing ratio), according to its acid number of pattern function Relationship Prediction, and compare with measured value.
4) blind sample checking: get the blind sample of some, measure oil sample conductivity variations value and predict acid number, measure its actual acid number with National Standard Method by modeling method (control same oil alkali mixing ratio).
5) chafing dish oil oleic acid pH-value determination pH: measure chafing dish oil conductivity variations value by modeling method (control same oil alkali mixing ratio).Utilize
"Y=0.0024x-0.01571 " predict its acid number, and measure with National Standard Method, every kind of method is all done three replicate determinations, and the measurement result comparative analysis sees Table 4.
Table 4: chafing dish oleic acid pH-value determination pH and relative error are relatively
As can be seen from Table 4, the mean value that method of the present invention is measured edible oil acid number and GB determination of acid-basetitration is respectively 4.31KOHmg/g and 4.35KOHmg/g, and two kinds of method measurement result deviations are 0.81%, do not have the significance difference opposite sex.From using on the reagent type, use the ethanol ether mixed solution to have strong volatility and certain toxicity in the national standard method.Method based on conductivity is used the equal non-volatility of reagent, and safety non-toxic can not cause environmental pollution.From operating personnel's operant level is required, no matter the GB acid base titration all requires the reviewer to have certain operating experience from titration process or on endpoint.And operator's technical ability is not had specific (special) requirements based on the conductance measurement acid number, simple and easy to do.This shows that it is fully feasible measuring chafing dish oleic acid value based on the method for conductivity, environmental pollution and little to the harm of operating personnel's health.
More than by three kinds of specific embodiments, having chosen three kinds of edible oils that belong to high, medium and low acid number, different potassium hydroxide solution concentration and different oily alkali blending ratio respectively is analyzed, as can be seen, edible oil acid value measuring method of the present invention, its result of edible oil who measures different acid numbers compares there was no significant difference with National Standard Method, illustrate that mensuration edible oil acid number of the present invention is feasible fully, method itself is not subjected to the influence of environmental baseline.During practical application operator's operative skill there is not specific (special) requirements, simple and easy to do.Little, the non-volatility of reagent use amount, safety non-toxic can not cause environmental pollution.Can require adjust oily alkali blending ratio ratio according to actual detected, select bigger oily alkali blending ratio as the edible oil acid number of being measured is smaller; On the contrary, when mensuration acid number is big, should select less oily alkali blending ratio to satisfy the requirement of different acid value measuring scopes and precision, be a kind of new method that detects the edible oil acid number.
Claims (1)
1. assay method based on the edible oil acid number of conductivity, it is characterized in that, this method utilizes conductivity meter as testing tool, and by setting up the acid number of acid number and the model determination edible oil that mixes potassium hydroxide solution conductivity variations value relation, concrete operations comprise the following steps:
1) modelling:
A, compound concentration are the potassium hydroxide solution of 0.04～0.06mol/L and measure its conductivity;
B, 5～10 of the edible oil sample of getting known acid number, the weight of each edible oil sample is 5.000g, places the conical flask back stand-by respectively, if edible oil sample is a solid fat, then heating is transformed into liquid;
C, according to measuring acid number scope and accuracy requirement, in each edible oil sample, add potassium hydroxide solution, its addition is: the edible oil sample quality: the potassium hydroxide solution volume is=1:3～1:10, vibration 3～5s, leave standstill 3～5min, directly the electrode with conductivity meter inserts in the alkali lye layer, measures alkali lye layer conductivity, calculates its conductivity variations value;
D, set up the funtcional relationship of edible oil acid number and conductivity variations value;
2) modelling verification:
It is known and be different from the edible oil of modeling oil sample kind and grade to get acid number, set by step 1) B step disposes 3～10 oil samples respectively, set by step 1) C step control same oil alkali blending ratio, measure alkali lye layer conductivity variations value respectively, predict the oil sample acid number according to institute's established model, and compare with actual acid number.The prediction of checking oil sample acid number and measured value relative deviation≤10%, predicted value and actual value related coefficient 〉=0.95;
3) blind sample checking:
Get the blind sample of some, set by step 1) B step disposes oil sample respectively, set by step 1) C step control same oil alkali blending ratio, vibration 3～5s, leave standstill 3～5min, directly the electrode with conductivity meter inserts in the alkali lye layer, measures the conductivity variations value of each alkali lye layer, the acid number of the blind sample of setting up by step 1) of model prediction; Other adopts GB/T 14489.3-1993 National Standard Method to measure the acid number of blind sample, predicted value and measured value relative deviation≤10%;
4) model is used:
Set by step 1) model of setting up, get oil sample 5.000g to be measured, set by step 1) C step control same oil alkali blending ratio, vibration 3～5s, leave standstill 3～5min, directly the electrode with conductivity meter inserts in the alkali lye layer, measures alkali lye layer conductivity variations value, model prediction oil sample acid number is set up in utilization, obtains the acid number of this edible oil.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1791796A (en) * | 2003-01-20 | 2006-06-21 | 洛桑生态综合技术联合公司 | Device for measuring the quality and/or degradation of a fluid, particularly a food oil |
| CN101387612A (en) * | 2008-07-23 | 2009-03-18 | 昆明理工大学 | Method for detecting waste oil in qualified edible oil |
-
2010
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1791796A (en) * | 2003-01-20 | 2006-06-21 | 洛桑生态综合技术联合公司 | Device for measuring the quality and/or degradation of a fluid, particularly a food oil |
| CN101387612A (en) * | 2008-07-23 | 2009-03-18 | 昆明理工大学 | Method for detecting waste oil in qualified edible oil |
Non-Patent Citations (1)
| Title |
|---|
| 《中国油脂》 20091231 吉礼等 《电导率法快速甄别泔水油的研究》 第34卷, 第3期 * |
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| CN102830087A (en) * | 2011-09-26 | 2012-12-19 | 武汉工业学院 | Method for quickly identifying food waste oils based on near infrared spectroscopy |
| CN102507379A (en) * | 2011-11-16 | 2012-06-20 | 张峰 | Detection method for checking whether edible oil contains illegal cooking oil |
| CN102507379B (en) * | 2011-11-16 | 2016-09-28 | 深圳市先波科技有限公司 | A kind of check the detection method whether having waste oil in edible oil |
| CN102854228A (en) * | 2012-09-04 | 2013-01-02 | 西北农林科技大学 | Edible oil peroxidation value determination method based on conductivity |
| CN102854228B (en) * | 2012-09-04 | 2014-06-11 | 西北农林科技大学 | Edible oil peroxidation value determination method based on conductivity |
| CN104076069A (en) * | 2013-12-04 | 2014-10-01 | 浙江工商大学 | Pork storage time detection method |
| CN106716118A (en) * | 2015-05-15 | 2017-05-24 | 株式会社爱宕 | Oil degradation meter and method for evaluating oil degradation |
| US10429332B2 (en) | 2015-05-15 | 2019-10-01 | Atago Co., Ltd | Oil degradation meter and method for evaluating oil degradation |
| CN106716118B (en) * | 2015-05-15 | 2020-03-24 | 株式会社爱宕 | Grease aging meter and grease aging degree evaluation method |
| CN113125513A (en) * | 2019-12-31 | 2021-07-16 | 石河子大学 | Method for measuring and calculating osmotic potential and conductivity of saline-alkali soil |
| CN111474294A (en) * | 2020-04-28 | 2020-07-31 | 广东博创佳禾科技有限公司 | Ralstonia solanacearum solution titration system |
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