JP2770106B2 - Qualitative and quantitative analysis of organic matter in cement or hardened cement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for qualitatively and quantitatively analyzing organic substances contained in cement or hardened cement.

[0002]

2. Description of the Related Art Conventionally, various organic admixtures have been added to cement in order to improve the performance and function of structural concrete. Even a small amount of these organic admixtures (about 0.1 to 1 kg / m ³ ) greatly affects the fluidity of fresh concrete and various physical properties after hardening. In addition, the effect varies significantly depending on the type and amount of the organic component contained. Therefore, it is important to conduct a qualitative or quantitative analysis of the organic components contained in the hardened concrete in examining the difference in the fluidity of the fresh concrete and various physical properties of the hardened concrete. In particular, when problems such as abnormal setting or poor curing occur,
It is necessary to make sure that the appropriate admixture has been added in the appropriate amount.

[0003] On the other hand, various types of cement products for producing various functions during or after hardening by adding an organic compound to cement in advance have been manufactured. It is important to conduct qualitative and quantitative analysis of the organic components contained in these products in order to control the quality of the products and to investigate the causes of abnormalities in performance during use.

In general, products made by adding an organic compound to cement or a mixture of cement and other inorganic substances, or organic compounds used for structural concrete include formalin condensate of naphthalene sulfonate, melamine sulfonic acid Formalin condensate of salt, lignin sulfonate, citric acid or its salt, sodium gluconate,
Examples include celluloses and sugars. In addition, many organic compounds are used as organic admixtures, and there are not a few admixtures composed of a plurality of components. However, an effective qualitative method for these organic components in cement or hardened cement has not been established so far, and only a quantitative method for a specific component when the organic component to be contained is known exists. Was.

[0005] Examples of the quantitative methods reported include an iodometric method, a colorimetric method using sodium nitrite and a gas chromatographic method for ligninsulfonate, and a high performance liquid chromatograph for a formalin condensate of naphthalenesulfonate. There is a method based on a graph, and a method based on colorimetry has been known for citric acid, its salts and saccharides. These methods are less versatile due to the limited number of organic components of interest, and when combined with other admixtures or other admixtures, analysis is difficult due to interference with other coexisting components. Often cannot. Further, in order to elute organic substances from the cement or the cured cement, pretreatment such as dissolution of the cement or the cured cement with an acid and extraction of organic components from the cement or the cured cement with an alkali is required. Normal,
The pretreatment requires a complicated operation and requires a long analysis time, and in the hardened cement, the organic component is strongly adsorbed by the cement particles, and the recovery is low.

On the other hand, as a rapid analysis method requiring no pretreatment, a quantitative method by pyrolysis gas chromatography has been reported for a formalin condensate of ligninsulfonate or naphthalenesulfonate. This involves instantaneously heating cement or hardened cement to release contained organic components from the sample, separating the generated thermal decomposition products by gas chromatography, and obtaining peaks due to the contained organic components. This is a method for performing quantification from the area of the sample. In this method, the organic components are desorbed from the cement or hardened cement by heat, so that it does not require pretreatment such as extraction or acid decomposition, and is excellent in rapidity, and the pyrolysis products are isolated by gas chromatography. Therefore, there is an advantage that it is not affected by other coexisting components. Furthermore,
By using a detector having a qualitative ability such as an infrared spectrophotometer or a mass spectrometer, a qualitative analysis of the added organic component can also be performed.

[0007]

However, most of the organic components used as admixtures described above contain many hydroxyl groups and carboxyl groups in the molecule and are strongly bonded to calcium in cement particles. It is difficult to desorb, and the pyrolysis products are very polar, so there is a problem in sensitivity, resolution and reproducibility in gas chromatography analysis, and as a result, applicable analytes are very limited Met.

Accordingly, an object of the present invention is to provide a quick and versatile qualitative and quantitative analysis method by solving the above-mentioned problems of the pyrolysis gas chromatography method.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems in the pyrolysis gas chromatography method.
An alkyl derivatizing agent is added to a sample in advance, and the heat treatment is performed to reduce the adsorptive power to the cement particles, thereby improving the sensitivity and the degree of separation in gas chromatographic analysis.

A sample to be analyzed is ground and dried in advance. Drying can be carried out by heating or under reduced pressure, but drying under reduced pressure is desirable in order to prevent decomposition of organic components in the sample.

The alkyl derivatizing agents include tetramethylammonium hydroxide, trimethylselenium hydroxide, trimethylsulfonium hydroxide and trimethylanilium hydroxide as methylating agents, and tetraethylammonium hydroxide as ethylating agents. Side, triethylselenium hydroxide, triethylsulfonium hydroxide and the like can be used. Among them, tetramethylammonium hydroxide is particularly preferred, and the hydroxyl group and carboxyl group contained in the molecule of the organic component in the sample are methoxy group and methoxycarbonyl which are inactive with respect to calcium in cement or a column of gas chromatograph. Each substituted with a group.

Alkyl derivatization can be carried out simultaneously with thermal decomposition, but since the derivatization reaction may occur unevenly or reduce the thermal decomposition efficiency,
After the derivatization treatment is performed in advance, it is desirable to perform analysis by pyrolysis gas chromatography. The amount of the derivatizing agent, the heating temperature, and the heat treatment time are not particularly limited as long as the derivatization is efficient and stable, but the heating temperature is determined by the organic component contained in the sample. Below the decomposition temperature. Further, excessive addition of the derivatizing agent is not preferable because the peak of the residue may overlap with the peak caused by the thermal decomposition product of the organic component contained in the sample. Furthermore, the thermal decomposition temperature and thermal decomposition time of the derivatized sample are not particularly limited as long as the temperature and time are such that the efficiency of desorption of the organic component from the sample is as high as possible and stable.

An apparatus used for thermally decomposing an organic component in a sample is configured such that when a pyrolysis product is sent to a gas chromatograph, it is converted into a gas having a vapor pressure exceeding a certain limit at a set column temperature. There is no particular limitation as far as possible. Also,
Gas chromatography is not particularly limited as long as these pyrolysis products can be sufficiently separated. F as a detector
Although an ID, an infrared spectrophotometer, a mass spectrometer, or the like can be used, a mass spectrometer is preferable when qualitative and quantitative measurements are performed simultaneously.

A qualitative method using the above mass spectrometer is to detect mass ions over a wide mass range,
The compound is specified from the obtained mass spectrum. In the pyrolysis gas chromatograph method, the mass spectrum of the obtained peak is attributable to the pyrolysis product, and a method of estimating the original compound is used therefrom.
In addition, when the methyl derivatization is performed, the hydroxyl group and the carboxyl group in the molecule are substituted, and this must be taken into consideration.

On the other hand, in the quantitative operation, among the obtained peaks, the area of at least one peak whose area is directly proportional to the amount of the organic component in the sample is determined by a calibration curve prepared in advance. This is done by plotting
At that time, if the concentration of organic substances in the sample is low, it is disadvantageous in terms of sensitivity to detect mass ions over a wide mass range, and therefore, the quantitative To detect peaks. In addition, in the qualitative analysis at a low concentration of the organic component contained, only the mass ions unique to the organic substance expected to be added are monitored, and the determination is made based on the presence or absence of the peak. Hereinafter, examples of the present invention will be described.

[0016]

EXAMPLES The following conditions were common to all samples. (Sample) All samples to be analyzed are coarsely crushed in advance,
Further, after finely pulverized in a stainless steel mortar, vacuum-dried a 150 μm sieve through a sieve for 24 hours to obtain 10 ± 0.
1 mg was used. (Apparatus) Pyrolyzer JHP-2 type Curie Point Pyrolyzer (Nippon Kagaku Kogyo) Gas chroma HP5890A (Hewlett-Packard) Detector HP5870B (Huered Packard) Column DB1701 (J & W) 30m × 0.2
5 mm i. d 0.25 μm f. d Carrier gas Helium (alkyl derivatization treatment) Derivatizing agent 10% methanol solution of tetramethylammonium hydroxide (Tokyo Kasei) Addition amount 20 μL Heating temperature 120 ° C Heating time 30 seconds (Measurement conditions) Thermal decomposition temperature 764 ° C Monitor ion (m / e) 33-300

Example 1 Determination of Sodium Gluconate in Hardened Cement FIG. 1 shows a pyrogram of a hardened cement to which 1 wt% of sodium gluconate was added, which was monitored with mass ions of 33 to 300. No peak was detected from the untreated sample that was not subjected to methyl derivatization, but a peak due to sodium gluconate was detected by derivatization. The mass spectra of peak 1 and peak 2 shown in FIG. 1 are shown in FIGS. 2 and 3, respectively. FIG. 4 shows that the additive amounts are 0.1%, 0.2% and 0.3%.
2 shows a calibration curve created from the peak area obtained by monitoring only the mass ion of m / e = 159 present in the mass spectrum for the cement hardened material of Example 1. As is clear from this figure, it is understood that linearity is obtained in the calibration curve, and that sodium gluconate in the cured product can be quantified by methyl derivatization.

Example 2 Determination of Sodium Citrate in Hardened Cement FIG. 5 shows sodium citrate (1 mg /
10 shows a pyrogram when no treatment and methyl derivatization treatment were performed. In addition, FIG. 6 shows the mass spectrum of the peak indicated by ★ in the figure. Further, by using the characteristic ions 68 and 126 in the respective mass spectra, in the cured product (0.3 wt%)
Fig. 7 shows the results of detection of sodium citrate in
Shown in No peak was detected without treatment, but the derivatization enabled detection of a peak due to sodium citrate. When a calibration curve was prepared by changing the concentration of sodium citrate, the results shown in FIG. 8 were obtained. This indicates that methyl derivatization is effective for the determination of sodium citrate in the cured product in this order.

Example 3 Determination of Saccharose in Hardened Cement FIG. 9 shows saccharose (1 mg / 10 μm) in an aqueous solution.
1 shows a pyrogram when no treatment and methyl derivatization treatment of l) were performed. In addition, FIG. 10 shows the mass spectrum of the peak indicated by ★ in the figure. FIG. 11 shows the results of detection of saccharose in the cured product (0.3 wt%) using the ions 95 and 118 in the respective mass spectra. No peak was detected without treatment, but the peak derived from saccharose became possible by methyl derivatization. FIG. 12 shows a calibration curve created by changing the concentration of saccharose.
The result as shown in FIG. This indicates that the amount of saccharose added in the above order has sufficient quantitativeness.

Example 4 Qualitative Analysis of Retarding Components in a Mixture of Multiple Organic Substances and Cement By comparing a product obtained by mixing an AE agent and a water reducing agent with cement and a product obtained by further adding a retarder thereto,
A model experiment was conducted to determine the qualitative properties of the delay component added to the latter by methyl derivatization. The amount of the organic substance added was 0.1 wt% with respect to the cement. FIG. 13 shows a pyrogram obtained by measuring both without treatment. No change was observed in the retention time and relative intensity of each peak. On the other hand, FIG. 14 shows the result when the methyl derivatization treatment was performed. According to this, in the system to which the retarder was added, a peak not observed in the system without the retarder was observed. Next, the mass spectrum of this peak is shown in FIG. This mass spectrum is in good agreement with the mass spectrum of the methyl-derivatized sodium citrate shown in FIG. 6 and also corresponds to the retention time.
This indicates that the added delay component is sodium citrate.

[0021]

As described above, according to the qualitative and quantitative analysis methods for organic substances in the cement or hardened cement according to the present invention, even for compounds which were difficult to analyze by conventional pyrolysis gas chromatography, Methyl derivatization enables qualitative and quantitative determinations, and also has the effect of not impairing the advantages of conventional pyrolysis gas chromatography, such as rapidity and the effect of not being affected by other components.

[Brief description of the drawings]

FIG. 1 is a pyrogram of a hardened cement to which sodium gluconate has been added.

FIG. 2 is a mass spectrum diagram of peak 1 shown in FIG.

FIG. 3 is a mass spectrum diagram of a peak 2 shown in FIG.

FIG. 4 is a mass ion calibration curve of m / e = 159 present in a mass spectrum.

FIG. 5 is a pyrogram of a hardened cement to which sodium citrate has been added.

FIG. 6 is a mass spectrum diagram of a peak indicated by ★ in FIG.

FIG. 7 is a detection diagram of sodium citrate in a cured product using ions 68 and 126.

FIG. 8 is a calibration curve diagram when the concentration of sodium citrate is changed.

FIG. 9 is a pyrogram of a hardened cement to which saccharose has been added.

FIG. 10 is a mass spectrum diagram of a peak indicated by ★ in FIG.

FIG. 11 is a diagram showing detection of saccharose in a cured product using ions 95 and 118.

FIG. 12 is a calibration curve diagram when the concentration of saccharose is changed.

FIG. 13 shows a cement to which an AE agent and a water reducing agent have been added;
Pyrogram comparing cement with a retarder added.

FIG. 14 is a pyrogram obtained when a methyl derivatization treatment is performed on the sample.

FIG. 15 is a mass spectrum diagram of a peak indicated by ★ in FIG.

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-5-322865 (JP, A) JP-A-3-262963 (JP, A) (58) Fields investigated (Int.Cl. ⁶ , DB name) G01N 30/06 G01N 30/72 G01N 30/74 G01N 30/86 G01N 33/38

Claims (1)

(57) [Claims] 1. A sample consisting of a mixture of an organic admixture and cement or a cement hardened material to which an organic admixture is added, after adding an alkyl derivatizing agent, heat-treating the sample to form a sample in the sample. After performing alkyl derivatization of the contained organic admixture component, the sample is thermally decomposed,
The resulting pyrolysis products were separated by gas chromatography, retention time of the peak of each component on the pyrograms, or infrared spectrum in the case of using an infrared spectrophotometer detector, mass spectrometer to the detector A method for qualitatively and quantitatively analyzing organic substances in cement or hardened cement to which an organic admixture is added, wherein qualitative analysis is carried out by mass spectrum and peak areas are quantified when is used.