Taking into consideration of such circumstances, in s, by combining sample decomposition device that was used in CHN automatic analysis, and auto-sampler as well as suppressor type IC device, fundamental investigation for the automatization had reported 8 in the purpose of achieving improvement of analysis efficiency and labor saving. In the wake of retirement from the company, a small company had founded and started reinvestigation of development for automatic combustion analysis system of halogens and sulfur.
In this decade duration, 3 different types of systems were introduced into the market 9 In these types, organic trace elemental analysis system 11 that was initially-staged developed in has added several modifications up to now. In this report, background and achievement for organic trace elemental analysis system are described in. In conjunction with, 5-element simultaneous analysis method has established by creating organic calibration curve utilizing newly-developed standard reagent that contains 4 kinds of halogens and sulfur. Subsequently, by pinpointing the cause of carry-over as the blank, its reduction has achieved and consequently accompanying high sensitivity measurement is possible, so that it is applied both for micro analysis sample amount: 1 to 10mg and for ultra-micro analysis sample amount: 0.
By rapidity for combustion and chromatogram development, analysis time is significantly shortened, and as our target, rapid analysis of 5 or 6 samples per an hour is realized. By introducing clarified air from the outlet side of the combustion tube, combustion residue materials are not attached on the tip part of the combustion tube. This contriving way enables to achieve reduction of carry-over conspicuously. Measuring condition of IC and combustion system is indicated in.
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Reagents Sodium carbonate and sodium hydrogen carbonate for resolving solution JIS special grade, Wako Chemical are respectively solved into pure water, then prepared as 3. Absorption solution is newly prepared on daily basis. In order to create calibration curve, organic calibration curve method stipulated in ion chromatography general rule JIS K is applied for. 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. Organic sample, that solely or plurally contains halogens and sulfur, is weighed on the boat made from platinum or ceramic, and set the boat on the auto-sampler.
Sample is introduced automatically into the flush heater part and combustion time is estimated for 3 to 5 minutes. The sequential processes, exchange of the absorption solution, introduction to the analytical column, washing for the absorption bottle and filling of absorption solution for subsequent sample, are automatically implemented. Meanwhile, chromatogram is developed in parallel, and 4 kinds of halogens ions and sulfur ion produced from organic compound are consecutively eluted within 9 minutes. By combustion, halogens F, Cl, Br, I and sulfur S in the sample are transformed to halides and halogen gas, while sulfur becomes to sulfuric acid and sulfurous acid gas.
Thus far, simultaneous analysis of reduction-required bromine and iodine, and oxidation-required sulfur, is regarded as in difficult way, and analysis was implemented respectively.
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For the absorption solution, aqueous solution adding a few amount of hydrogen peroxide and hydrazine hydrate, such as in , or 2mM sodium carbonate solution, is appropriately used according to the purpose. As described later in , 2mM sodium carbonate solution is desirable for the sample containing bromine and sulfur simultaneously. Therefore effect of column temperature, that affects separation of anion ion species, has considered.
As a result, retention time fluctuation accompanying with temperature rising is insignificant for divalent anions, while for monovalent iodide ion, its retention time is drastically decreased by endothermic reaction accompanying with temperature rising.
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All ion species are eluted within 9 minutes, and rapid separation was achievable even in addition of combustion supportive agent WO 3. Reduction of carry-over The point taking into consideration most in implementing speeding-up and ultra-micronization of CIC method, is contamination in the carrier gas and the influence by carry-over previous sample is remained in the phase as residue. At upstream side, impurity in the carrier gas is absorbed and removed by washing with 2 washing bottles. Also combustion product is adhered at the tube path close to exhaustion outlet of the combustion furnace at downstream side, and it may cause conspicuous disordering of the baseline and its reason is specifically determined.
Thus, in order to prevent adsorption to the combustion part, the method is adopted that considerable amount of clean air is introduced from the outside of the needle tube 15 , too. Standard reagent, NAC-st4, is used for simultaneous test for the carry-over. This method enables to obtain the carry-over values for total 5 elements of F, Cl, Br, I and S at just one measurement. Chromatograms of NAC-st4 and its carry-over measurement are illustrated in , and test results are shown in , respectively.
In any respective element, carry-over quantity just after NAC-st4 measurement is less than 0.
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Either method is used along with measuring purpose and calibration curve is created and quantitative calculation is executed. However 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 total 5 elements of 4 kinds of halogens and sulfur in one compound, and it enables to analyze simultaneously, creation time of calibration curve as well as analysis time for respective element can be shortened drastically. As in , organic calibration curves of 5 kinds of elements accompanying with combustion of NAC-st4, have good correlation with correlation coefficient r 2 more than 0.
In this method, even 3 compounds contain sulfur, normal bromine contents are confirmed.
Reasons that good result was not obtained with the method that pointed out the problem 16 are assumed that most bromines exist as Br 2 in acidic combustion gas accompanying with sulfur combustion, also since Br 2 is not absorbed into water and sufficient reduction is not performed in the absorption solution, a part of Br 2 is volatilized to out of phase. Organic Elemental Analysis: Ultramicro, Micro, and Trace Methods is a chapter text that presents the methods for ultramicro, micro, and trace organic elemental analysis for commercial routine analysis.
Each chapter of this book describes the important features of the methods evaluated, such as gas chromatography, wet absorption, spectrophotometry, diffusion, extraction, flame photometry, and dead-stop titration.
These methods are classified into dynamic, multielement, and automatic determination methods. The advantages and limitations, as well as the speed, accuracy, reliability and economic aspects of these methods are examined. Considerable chapters are devoted to the analysis of various elements, including carbon, hydrogen, nitrogen, oxygen, sulfur, chlorine, bromine, iodine, fluorine, and phosphorus.
Organic and analytical chemists, as well as chemistry teachers and students will find this work invaluable. This action might not be possible to undo.
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