CN115561389A - Method for detecting white granulated sugar whole water - Google Patents
Method for detecting white granulated sugar whole water Download PDFInfo
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- CN115561389A CN115561389A CN202110742869.3A CN202110742869A CN115561389A CN 115561389 A CN115561389 A CN 115561389A CN 202110742869 A CN202110742869 A CN 202110742869A CN 115561389 A CN115561389 A CN 115561389A
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- granulated sugar
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- G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
- G01N31/16—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using titration
- G01N31/168—Determining water content by using Karl Fischer reagent
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Abstract
The invention discloses a detection method of white granulated sugar whole water. According to the method for detecting the white granulated sugar total water, provided by the invention, the white granulated sugar is quickly dissolved in batches by using anhydrous formamide under a sealed condition, and then the Karl Fischer moisture detector is added for detecting the white granulated sugar total water, so that the white granulated sugar total water can be quickly detected in batches; the method overcomes the use difficulty of extremely strong water absorption of the anhydrous formamide by utilizing the characteristic that the white granulated sugar can be dissolved in the anhydrous formamide, and the anhydrous formamide and anhydrous methanol mixed solvent (the content of the anhydrous formamide is lower than 50 percent of the total amount of the mixed solvent) can be used as a working medium of the Karl Fischer moisture detector for the total moisture of the white granulated sugar, can realize the batch rapid detection of the total moisture of the white granulated sugar, and has accurate and reliable detection results.
Description
Technical Field
The invention relates to the technical field of sugar manufacturing, in particular to a detection method of white granulated sugar whole water.
Background
With the continuous progress of scientific research development, people gradually deepen the understanding of the moisture content in products, and more production practices and researches show that the moisture content can have an important influence on the quality of the products, so that the moisture content is listed as an important detection index of various substances, and the quantitative analysis of the moisture becomes one of the basic items of the physicochemical analysis of various substances. The commonly used method for measuring the moisture of the white granulated sugar in China is a constant-temperature drying method recommended by GB/T317, namely 105 ℃/2h or 130 ℃/18min, the moisture measured by the method is the surface moisture contained in the white granulated sugar, namely the drying weight loss, and the moisture in the white granulated sugar also contains the internal moisture besides the surface moisture as can be known from literature. The existence of the 2 kinds of water constitutes the total water in the white granulated sugar, namely the total water, so that the constant-temperature drying method cannot completely represent the total water of the white granulated sugar.
Research shows that the Karl Fischer titration method can detect the total moisture in the white granulated sugar, and the Honeyville provides a method for detecting the total moisture of the white granulated sugar by titration by using a mixed solution of anhydrous methanol and anhydrous formamide at 50 ℃ as a working medium (solvent) and adopting the Karl Fischer method. White granulated sugar is difficult to dissolve in methanol, so that the Karl Fischer titration method using methanol as a common working medium (solvent) cannot directly detect the total moisture of the white granulated sugar; the method provided by Honeyville still has the defects of slow dissolution of white granulated sugar in the titration cup, long detection time, poor stability of detection results, high price of the heatable titration cup and the like, and cannot meet the requirement of sugar manufacturing enterprises on detecting and monitoring the total moisture of the white granulated sugar, particularly large-particle white granulated sugar; the anhydrous formamide has strong water absorption, higher requirements on the humidity of the use environment and sealing operation, and higher use difficulty. Therefore, it is necessary to provide a method for detecting the white granulated sugar water to solve the above problems.
Disclosure of Invention
The invention aims to provide a method for detecting white granulated sugar whole water, which solves the problem that the existing method for detecting the white granulated sugar whole water cannot meet the requirement of sugar manufacturing enterprises on detecting and monitoring the white granulated sugar whole water.
The invention provides a method for detecting white granulated sugar whole water, which comprises the following steps:
step one, emptying a titration cup of a Karl Fischer moisture detector, and adding anhydrous methanol into a solvent bottle of the Karl Fischer moisture detector;
secondly, drifting is carried out in the titration cup, wherein the drifting comprises the step of reacting a titrant with water and absolute methanol in the titration cup to consume the water in the titration cup so as to achieve dynamic balance; calibrating the titrimeter of the titrant, wherein the calibrating comprises the steps of sampling 10 mu l of ultrapure water by using a micro-sampler, calibrating the titrimeter of the titrant, measuring for three times at intervals, and then taking the average value of the titrimeter and recording as T;
after drifting, taking 5ml of anhydrous formamide by using an injector, measuring the moisture content in the anhydrous formamide, measuring for 2 times, taking an average value, and recording as CV02;
weighing 1-2g of sugar sample, recording the weight of the sugar sample as C00, filling the sugar sample into a 30ml dry anhydrous penicillin bottle, covering a rubber stopper of the penicillin bottle, sealing, adding 5ml of anhydrous formamide into the penicillin bottle by using an injector, and heating and stirring at 45 ℃ until sugar particles are completely dissolved;
step five, extracting all the solution in the penicillin bottle at one time by using an injector, quickly injecting a sample into a titration cup with anhydrous methanol as a working medium after drifting, wherein the content of anhydrous formamide in the titration cup is lower than that of the anhydrous methanol, and recording the titration amount as EP1;
step six, calculating the total water content of the white granulated sugar sample
Further, prior to the step of emptying the titration cup of the karl fischer moisture detector, the method further comprises:
and (4) checking whether all pipelines of the Karl Fischer moisture detector are correctly connected or not and whether the molecular sieve drying agent is invalid or not, and ensuring that the liquid level of the waste liquid bottle is below 800 ml.
Further, prior to the step of emptying the titration cup of the karl fischer moisture detector, the method further comprises:
and (4) checking whether a power supply and a stirring switch are turned on, whether blank current is stable and whether the stirring speed is proper.
Further, prior to the step of emptying the titration cup of the karl fischer moisture detector, the method further comprises:
after the karl fischer moisture tester was tested on the same day, the karl fischer reagent was emptied and then rinsed with methanol before being used again.
Further, prior to the step of emptying the titration cup of the karl fischer moisture detector, the method further comprises:
the Karl Fischer moisture analyzer should be kept away from a strong magnetic field to avoid the phenomenon of electron jumping and abnormality during work.
Further, the method further comprises: and repeating the first step to the sixth step to obtain the total water content of a plurality of white granulated sugar samples, and calculating the average value of the total water content of the plurality of white granulated sugar samples to be used as the total water content of the final white granulated sugar sample.
Further, the method further comprises: and repeating the first step to the sixth step to obtain the total water content of a plurality of white granulated sugar samples, and taking the median of the total water content of the plurality of white granulated sugar samples as the final total water content of the white granulated sugar samples.
Further, in the step of emptying the titration cup of the Karl Fischer water content detector, the titration cup is emptied when the liquid level of the titration cup exceeds 120 ml.
Further, in the step of adding anhydrous methanol to the solvent bottle of the Karl Fischer moisture meter, 60ml or more of anhydrous methanol was added, the anhydrous methanol passing through the electrode.
Further, in the step of calibrating the titrant, the titrant is calibrated again at intervals or when the titrant is replaced.
The invention has the following beneficial effects: according to the method for detecting the white granulated sugar total water, provided by the invention, the white granulated sugar is quickly dissolved in batches by using anhydrous formamide under a sealed condition, and then the Karl Fischer moisture detector is added for detecting the white granulated sugar total water, so that the white granulated sugar total water can be quickly detected in batches; the method overcomes the use difficulty of extremely strong water absorption of the anhydrous formamide by utilizing the characteristic that the white granulated sugar can be dissolved in the anhydrous formamide, and the anhydrous formamide and anhydrous methanol mixed solvent (the content of the anhydrous formamide is lower than 50 percent of the total amount of the mixed solvent) can be used as a working medium of the Karl Fischer moisture detector for the total moisture of the white granulated sugar, can realize the batch rapid detection of the total moisture of the white granulated sugar, and has accurate and reliable detection results.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a schematic diagram of a detection method of white granulated sugar whole water provided by the invention.
Detailed Description
It should be noted that, in the present application, the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments. It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
For ease of description, spatially relative terms such as "over 8230 \ 8230;,"' over 8230;, \8230; upper surface "," above ", etc. may be used herein to describe the spatial relationship of one device or feature to another device or feature as shown in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary terms "at 8230; \8230; 'above" may include both orientations "at 8230; \8230;' above 8230; 'at 8230;' below 8230;" above ". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
Exemplary embodiments according to the present application will now be described in more detail with reference to the accompanying drawings. These exemplary embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. It is to be understood that these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art, and in the drawings, the thicknesses of layers and regions are exaggerated for clarity and the same devices are denoted by the same reference numerals, and thus the description thereof will be omitted.
Referring to fig. 1, an embodiment of the present invention provides a method for detecting white granulated sugar in whole water, including the following steps:
step one, emptying a titration cup of the Karl Fischer moisture detector, and adding anhydrous methanol into a solvent bottle of the Karl Fischer moisture detector.
Secondly, drifting is carried out in the titration cup, wherein the drifting comprises the step of reacting a titrant with water and absolute methanol in the titration cup to consume the water in the titration cup so as to achieve dynamic balance; and calibrating the titrimeter of the titrant, wherein the calibrating comprises the steps of sampling 10 mu l of ultrapure water by using a micro-sampler, calibrating the titrimeter of the titrant, measuring for three times at intervals, and then taking the average value of the titrimeter, and recording the average value as T.
And step three, after drifting, taking 5ml of anhydrous formamide by using an injector, measuring the moisture content in the anhydrous formamide, measuring for 2 times, taking an average value, and recording as CV02.
Weighing 1-2g of sugar sample, recording the weight of the sugar sample as C00, filling the sugar sample into a 30ml dry anhydrous penicillin bottle, covering a rubber stopper of the penicillin bottle, sealing, adding 5ml of anhydrous formamide into the penicillin bottle by using an injector, and heating and stirring at 45 ℃ until sugar particles are completely dissolved.
And step five, extracting all the solution in the penicillin bottle at one time by using an injector, quickly injecting the solution into a titration cup with anhydrous methanol as a working medium after drifting, wherein the content of anhydrous formamide in the titration cup is lower than that of the anhydrous methanol, and recording the titration amount as EP1.
Sixthly, calculating the total water content of the white granulated sugar sample
The detection method of the white granulated sugar whole water is described in detail with reference to specific embodiments.
Firstly, whether all pipelines of the Karl Fischer moisture detector are correctly connected and whether the molecular sieve drying agent is invalid (discolored) are checked, the liquid level of a waste liquid bottle is ensured to be below 800ml, and suck-back is prevented. And then, preparing, emptying a titration cup of the Karl Fischer moisture detector when the Karl Fischer moisture detector is not used for a long time or the liquid level of the titration cup exceeds 120ml, and adding more than 60ml of anhydrous methanol into a solvent bottle of the Karl Fischer moisture detector, wherein the anhydrous methanol needs to pass through an electrode.
Then, a calibration operation is performed. And (3) drifting is carried out before calibration, drifting is carried out in the titration cup, and the drifting comprises the step of reacting the titrant with water and anhydrous methanol in the titration cup, consuming the water in the titration cup and achieving dynamic balance so as to keep the anhydrous state in the titration cup, wherein the operation exists in the calibration, blank and sample measurement processes. And calibrating the titre of the titrant. The titrimetry is equivalent to how many mg of water can be consumed by 1ml of titrant, the water content in the sample can be converted only by knowing the titrimetry of the titrimeter, and the titrimetry can absorb water in the air over time, so that the titrimetry changes, therefore, the calibration comprises taking 10 mu l of ultrapure water by using a micro-sampler, calibrating the titrimetry of the titrimeter, and taking the average value of the titrimetry after measuring three times at intervals, which is recorded as T. Specifically, the calibration may be re-calibrated at intervals or when titrant is replaced.
Then, a blank operation is performed. The anhydrous formamide absorbs moisture in the air during use, and the calculation process needs to remove the moisture attached to the anhydrous formamide. After the drift, the equilibrium was normal (below 20. Mu.l/min). 5ml of anhydrous formamide is taken by a syringe, the moisture content in the anhydrous formamide is measured, and the average value is taken after 2 times of measurement and is recorded as CV02.
Then, sample preparation is performed. 1-2g of sugar sample (accurate to 0.1 mg) is quickly and precisely weighed, the weight of the sugar sample is recorded as C00, the sugar sample is filled into a 30ml dry anhydrous penicillin bottle (containing a rotor), a rubber plug of the penicillin bottle is quickly covered and sealed, 5ml of anhydrous formamide is taken by an injector and added into the penicillin bottle, and the mixture is heated and stirred at the temperature of 45 ℃ until sugar particles are completely dissolved.
Then, the sample measurement operation is performed. And (3) extracting all the solution in the penicillin bottle at one time by using a syringe, drifting, and then quickly injecting the sample into a titration cup with anhydrous methanol serving as a working medium. The content of anhydrous formamide in the titration cup is lower than that of anhydrous methanol, and if the content of anhydrous formamide in the titration cup is higher than that of the anhydrous methanol, side reaction can occur. The titration amount was recorded as EP1.
And finally calculating the total water content of the white granulated sugar sample. Total water content of white sugar sample
In this embodiment, prior to the step of emptying the titration cup of the karl fischer moisture detector, the method further comprises: and (4) checking whether a power supply and a stirring switch are turned on, whether blank current is stable and whether the stirring speed is proper. After the karl fischer moisture tester was tested on the same day, the karl fischer reagent was emptied and then rinsed with methanol before being used again. The Karl Fischer moisture analyzer should be kept away from a strong magnetic field to avoid the phenomenon of electron jumping and abnormality during work.
In an optional embodiment, the method further comprises: and repeating the first step to the sixth step to obtain the total water content of a plurality of white granulated sugar samples, and calculating the average value of the total water content of the plurality of white granulated sugar samples to be used as the final total water content of the white granulated sugar samples.
In another optional embodiment, the method further comprises: and repeating the first step to the sixth step to obtain the total water content of a plurality of white granulated sugar samples, and taking the median of the total water content of the plurality of white granulated sugar samples as the final total water content of the white granulated sugar samples.
According to the embodiment, the method for detecting the white granulated sugar total water provided by the invention has the advantages that the anhydrous formamide is utilized to realize batch quick dissolution of the white granulated sugar under a sealed condition, and the Karl Fischer moisture detector is added to detect the white granulated sugar total water, so that the batch quick detection of the white granulated sugar total water can be realized; the method overcomes the use difficulty of extremely strong water absorption of the anhydrous formamide by utilizing the characteristic that the white granulated sugar can be dissolved in the anhydrous formamide, and the anhydrous formamide and anhydrous methanol mixed solvent (the content of the anhydrous formamide is lower than 50 percent of the total amount of the mixed solvent) can be used as a working medium of the Karl Fischer moisture detector for the total moisture of the white granulated sugar, can realize the batch rapid detection of the total moisture of the white granulated sugar, and has accurate and reliable detection results.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A method for detecting white granulated sugar full water is characterized by comprising the following steps:
step one, emptying a titration cup of a Karl Fischer moisture detector, and adding anhydrous methanol into a solvent bottle of the Karl Fischer moisture detector;
secondly, drifting is carried out in the titration cup, wherein the drifting comprises the step of reacting a titrant with water and absolute methanol in the titration cup to consume the water in the titration cup so as to achieve dynamic balance; calibrating the titrimeter of the titrant, wherein the calibrating comprises the steps of sampling 10 mu l of ultrapure water by using a micro-sampler, calibrating the titrimeter of the titrant, measuring for three times at intervals, and then taking the average value of the titrimeter and recording as T;
after drifting, taking 5ml of anhydrous formamide by using an injector, measuring the moisture content in the anhydrous formamide, measuring for 2 times, taking an average value, and recording as CV02;
weighing 1-2g of sugar sample, recording the weight of the sugar sample as C00, filling the sugar sample into a 30ml dry anhydrous penicillin bottle, covering a rubber stopper of the penicillin bottle, sealing, adding 5ml of anhydrous formamide into the penicillin bottle by using an injector, and heating and stirring at 45 ℃ until sugar particles are completely dissolved;
step five, extracting all the solution in the penicillin bottle at one time by using an injector, quickly injecting a sample into a titration cup with anhydrous methanol as a working medium after drifting, wherein the content of anhydrous formamide in the titration cup is lower than that of the anhydrous methanol, and recording the titration amount as EP1;
sixthly, calculating the total water content of the white granulated sugar sample
2. The method for detecting the whole water of the white granulated sugar according to claim 1, wherein before the step of emptying the titration cup of the Karl Fischer water content detector, the method further comprises the following steps:
and (3) checking whether all pipelines of the Karl Fischer moisture detector are correctly connected or not and whether the molecular sieve drying agent is invalid or not, and ensuring that the liquid level of the waste liquid bottle is below 800 ml.
3. The method for detecting the whole water of the white granulated sugar according to claim 1, wherein before the step of emptying the titration cup of the Karl Fischer water content detector, the method further comprises the following steps:
and (4) checking whether a power supply and a stirring switch are turned on, whether blank current is stable and whether the stirring speed is proper.
4. The method for detecting the whole sugar water according to claim 1, wherein before the step of emptying the titration cup of the Karl Fischer water content detector, the method further comprises the following steps:
after the karl fischer moisture tester was tested on the same day, the karl fischer reagent was emptied and then rinsed with methanol before being used again.
5. The method for detecting the whole sugar water according to claim 1, wherein before the step of emptying the titration cup of the Karl Fischer water content detector, the method further comprises the following steps:
the Karl Fischer moisture analyzer should be kept away from a strong magnetic field to avoid the phenomenon of electron jumping and abnormality during work.
6. The method for detecting the white granulated sugar whole water as claimed in claim 1, wherein the method further comprises: and repeating the first step to the sixth step to obtain the total water content of a plurality of white granulated sugar samples, and calculating the average value of the total water content of the plurality of white granulated sugar samples to be used as the final total water content of the white granulated sugar samples.
7. The method for detecting the whole water of the white granulated sugar as claimed in claim 1, wherein the method further comprises: and repeating the first step to the sixth step to obtain the total water content of a plurality of white granulated sugar samples, and taking the median of the total water content of the plurality of white granulated sugar samples as the final total water content of the white granulated sugar samples.
8. The method for detecting the whole water of the white granulated sugar according to claim 1, wherein in the step of emptying the titration cup of the Karl Fischer water content detector, the titration cup is emptied when the liquid level of the titration cup exceeds 120 ml.
9. The method for detecting the whole water of the white granulated sugar according to claim 1, wherein in the step of adding the anhydrous methanol into the solvent bottle of the Karl Fischer water content detector, more than 60ml of the anhydrous methanol is added, and the anhydrous methanol passes through an electrode.
10. The method for detecting the white granulated sugar total water as claimed in claim 1, wherein in the step of calibrating the titrant, the titrant is calibrated again at intervals or when the titrant is replaced.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110742869.3A CN115561389A (en) | 2021-07-01 | 2021-07-01 | Method for detecting white granulated sugar whole water |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110742869.3A CN115561389A (en) | 2021-07-01 | 2021-07-01 | Method for detecting white granulated sugar whole water |
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