Knowledge


2018.06.28
CIC development and validation; May 26-28, 2016 at Iwate AIINA
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33rd Joint Symposium
83rd Organic micro analysis research meeting, Japan Analytical Chemistry Association,
101st The Society of Instrument and Control Engineers (SICE),
Technology Committee on Mechanical Metrology
At Iwate Prefecture Citizen’s Cultural Exchange Center (AIINA), May 26 – 28, 2016

Abstract: O-16

Development and validation of multifunctional halogens and sulfur analytical system by the small and medium-sized enterprise new one-making business

Hisomu Nagashima*1

A multifunctional halogens and sulfur analytical system has been developed by coupled combustion/ion chromatography (CIC). The system is composed by combustion furnace, absorption unit, auto-sampler and ion chromatograph. In this study, we have established a simultaneous determination for organic halogens (F, Cl, Br, I) and sulfur (S), based upon conductivity detection after decomposition in this automatic system using clean air. The method can be applied to the determination of organic samples within wide range of 1.0mg to 500mg.

1. Introduction

While the spread to the environment of the toxic substances has been regarded as a concerning and attentive problem internationally, and environmental regulation/restriction directives have been carried out. So the interest of halogens and sulfur analysis becomes increasing, and the demand for developing analytical instrument is required, that enables to measure multi-elements easily and in high speed procedure. However, it is not possible to measure solid and liquid sample or organic and inorganic sample just as it is, hence it is necessary to lead to ionic species by some sort of combustion pre-treatment method. In conventional method, combustion tube is made from quartz, so only organic samples are targeted substances; therefore it sometimes cannot be applied to analysis of metallic compounds and mineral samples.
Accordingly during this decade duration, author and collaborators have developed 3 different systems of multi-functional halogens and sulfur analytical system, by coupled combustion/ion chromatography (CIC) method 1) 2).
 1) For organic elemental analysis
 2) For environmental samples conforming to JIS regulation
 3) High temperature combustion system for organic/inorganic compatible type
Nonetheless, in order to comply with various samples, it is necessary to utilize several systems for adequate and prompt analysis. Here, we had an opportunity to be adopted subsidy project promoted by the government. On this occasion, from July, 2014 to June, 2015, we had investigated and developed “Multi-functional halogens/sulfur automatic combustion analysis system”, that satisfy prescribed inquiry.
Automatic combustion analysis system had newly developed with focusing on problematic points in conventional technologies. The system enables to combust the sample arbitrarily from low to high temperature, so that the functions of above-mentioned 3 kinds systems are gathered as in one system. Organic/inorganic compatible type automatic combustion analysis system 3) of halogens/sulfur had realized, and it is attainable to measure the samples from organic micro elemental analysis to a steel sample.
Even still in the developing stage, effective validation data were obtained by this system, we would like to introduce our achievement here.

*1 NAC Techno Service Co., Ltd., Tokyo and Chiba, Japan

2. Experiment

Automatic combustion analysis system:
The system of halogens/sulfur analysis is composed of combustion furnace (HNS-18), absorption unit (HSU-45), auto-sampler (THA-10L), manufactured collaboratively by Yanaco LID Company, and ion chromatograph. Overall view of the system is illustrated in Fig. 1, while the measuring conditions are described in Table 1.

Fig.1

Table1

Carrier gas:
Clean air is used as the carrier gas in place of cylinder gases (Ar, O2). No expensive inert gas and oxygen gas are used, also no need to assure piping and the system can be installed anywhere suitable; drastic reduction of running cost is achievable.
As for clarifying the air, trace amount of halogens and sulfur-based gases are decomposed through low-temperature electric furnace, and is subsequently washed by alkali solution, so that reduction of concerned potential blank has realized. Still more, for the samples that prescribes carrier gas, such as ceramic sample,

Fig2

Combustion boat:
Commercially procurable No. 2 magnetic boat is baked beforehand, and sample is weighed on the boat and set it on the auto-sampler. Boats after combustion are all collected including residues on them. Total residue can be quantitatively analyzed by other instruments such as fluorescent X-ray analyzer.
Sample boats after combustion/collection process are shown in Fig. 2, confirming in an orderly alignment.

Sample amount and containing quantity:
The system enables to measure wide range of sample amount, and samples specifying significantly different containing quantity; sample amount 0.1 to 500mg (0.5g), containing quantity 1ppm to 50%.

Ion chromatograph (IC) and electronic balance:
Dionex ICS-1600 type is used for the IC, while Mettler ultra-micro-electronic balance is used for the sample weighing.

Combustion standard:
For the standard sample, standard sample for organic elemental analysis (Kishida Chemical) is used, as well as multi-element containing standard samples (NAC-st1, NAC-st2 and NAC-st4 4)) are used, that were collaboratively developed between “Tokyo Metropolitan Industrial Technology Research Institute (TMITRI)” and “NAC Techno Service”. As for the synthesis of NAC-st4, byproduct was produced during synthetic process and so was quite troublesome. However, selective synthesis method was succeeded at TMITRI, and high purity reagent could be obtained only by re-crystallization method. These 3 reagents are introducing into the market, with respective quality test and analysis data sheet (test report) has attached.

3. Experimental results and consideration

3-1. Ion chromatogram of combustion product

Ion chromatogram accompanying to the combustion of NAC-st4 is sown in Fig. 3, and obtained theoretical plate number of respective ion are summarized in Table 2.
Each of 5 species ion indicates sharp peak, and its theoretical plate number is equivalent to HPLC, quite high number that is more than 10,000 steps.

Fig.3

table2

3-2. Creation of calibration curve

In order to create calibration curve by organic calibration curve method, it is required several times of standard sample measurement complying with respective element, hence simultaneous multiple elements analysis takes long time and effort.
In NAC-st4, it contains totally 5 elements of 4 kinds of halogens and sulfur in one compound, so it enables to analyze simultaneously, eventual creation time of calibration curve as well as analysis time for respective element can be shortened drastically. As shown in Fig. 4, organic calibration curves of 5 kinds of elements accompanying with combustion of NAC-st4, have good correlation with correlation coefficient (r2) more than 0.999.

Fig.4

3-3. Br analysis in S-containing sample

In case of simultaneous analysis for sulfur and bromine, it is pointed out that bromine’s analysis value becomes at negative and for this reason leads a lack of accuracy.
Bromine analysis has implemented with NAC-st4, normal analyzed values were obtained shown in Table 3.

Table3

4. Conclusion

In this paper, organic samples only are targeted, so we would like to extend the application for inorganic samples, too. And then, separation column that is used at this time (IonPac AS22, Dionex, ThermoFisher), indicates adequate separation ability for 4 kinds of halogens, sulfur, furthermore carbonate ion in balance, and substantiates high theoretical plate numbers that is equivalent to HPLC. However, after using the column a few months, 2 unknown peaks are observed just after F-ion peak. This unknown peak is increasing in correlation with increasing of hydrogen peroxide concentration in the absorption solution, and it sometimes affects to analysis of F-ion. Hereafter, we would like to consider the effect of hydrogen peroxide concentration in the absorption solution, as well as the optimization of the column separation.

Bibliography

1) H. Nagashima, Patent, No. 5266440 (2013)
2) H. Nagashima, Y. Dewa, Patent, No. 5399795 (2014)
3) H. Nagashima, Patent, No. 129359 (2015)
4) H. Ueno, H. Nagashima, et. al., Patent, No. 5572459 (2014)