Analysis of potassium citrate thermal cracking products under different pH conditions
At present, the research on cigarette paper additives mainly focus on reducing tar CO and improve the burning cigarette appearance, such as Zheng new  by high pressure ion chromatography (HPIC) determination of combustion several domestic and imported cigarette paper, found that several kinds of accelerant in cigarette paper samples are potassium citrate sodium. Liu Zhihua  studied the effect of citric acid sodium potassium mixed salt accelerant on mainstream smoke, that potassium citrate was significantly lower than the amount of sodium citrate in mainstream smoke effect, by adjusting the proportion of the two, can reduce CO. When smoking, cigarette paper additives and burned with cigarettes, will generate pyrolysis combustion process, cracking state will not only change the cigarette paper and the surrounding tobacco, while its pyrolysis products will flue gas composition on cigarette has certain influence on . The research on the pyrolysis products of cigarette paper additives has important significance for reducing the harm of cigarettes and improving the flavor. The domestic and foreign tobacco chemists have adopted technology of tobacco, tobacco flavor pyrolysis products conducted a lot of research by  Py2GC/MS. In recent years, the application of Py2GC/MS technology in cigarette paper pyrolysis of  fiber, cigarette paper additives in some reports, and the environmental impact of a pH of a cigarette paper additives of pyrolysis products are rarely reported. Therefore, the effect of acid and alkali environment on the pyrolysis products of potassium citrate was studied in order to provide reference for the development of cigarette paper additives.
1 materials and methods 1.1 materials of potassium citrate and potassium hydroxide (AR, Tianjin kwangfu Fine Chemical Industry Research Institute); 85% phosphate (food grade, Tianjin Rong Hong Chemical Co. Ltd.); deionized water. HP6890N/5972 type gas chromatography / mass spectrometry (Agilent); Pyroprobe2000 pyrolyzer (American CDS company); 75LmCAR/PDMS SPME head (American SUPEL2CO company); HR2200 electronic balance (0.0001g, Japan AND company). 1.2 samples of cracking and analysis of 50mL10% (mass fraction, the same below) of potassium citrate solution (pH8.36) 3, among them, one with a small amount of phosphoric acid 85% pH adjusted to 3.15, another pH adjusted to 12.14 with potassium hydroxide. The water solution of potassium citrate is absorbed by a micro syringe and placed in a special quartz tube for cracking, and the quartz tube is arranged in the heating wire of the thermal cracking apparatus, and the 10LL is subjected to thermal cracking in the atmosphere. Pyrolysis temperature: 300600900e. Pyrolysis is completed, remove the special cracking quartz tube, the solid phase microextraction (SPME) is inserted into the bottle head cracking of pyrolysis products were collected, after 70E, extraction 30min, remove the SPME head, high temperature gasification chamber and quickly into the GC/MS instrument, 2min 260e desorption time, desorption of pyrolysis products into GC/MS system for separation and identification using NIST, WI2LEY, standard library search area normalization method quantitative qualitative. The isolation and identification conditions were as follows: column: HP25MS ([email protected]@0.25mmd..F) capillary column; inlet temperature: 240e; carrier gas: 1mL/min, He; heating program: 50E (1m)
2e/min (in) 100e (1mi)
8e/min (n) 260e (5min); split ratio: 10B1. Interface temperature: 250E; ion (EI) source temperature: 230E; ionization energy: 70eV; quadrupole temperature: 150e; solvent delay time: 1.5min; mass scan range: 35~455amu. 2 results and Discussion on the effect of pyrolysis temperature on the pyrolysis products of potassium citrate pH3.15,8.36,12.14 potassium citrate aqueous solution under 300600 and 900e pyrolysis products see table 1~ table 3. For comparison, table 1~ Table 3 in the statistical classification of compounds.
(1) under 300E, pH3.15 potassium citrate aqueous solution to produce 17 kinds of substances. Among them, 9 aldehydes and ketones, 1 kinds of alcohol, lactone (Furaneol) class 1, benzene 3, 3 phenols, indicating the occurrence of the degradation of samples; 600E, pH3.15 of potassium citrate solution pyrolysis of 81 substances. Among them, 18 aldehydes and ketones, furans 3, 1 alcohol, 1 aromatic benzene, 10 species, 11 kinds of phenols, indene 13 kinds, 24 kinds of polycyclic aromatic hydrocarbons. Under pH3.15, 900e potassium citrate aqueous solution to produce 98 kinds of substances. Among them, 24 aldehydes and ketones, furans 5, 1 class 2 class furfuryl alcohol, aromatic hydrocarbons, benzene 12, 12 phenols, 16 indene, 26 kinds of polycyclic aromatic hydrocarbons. The result showed that the potassium citrate cracking was more complete and the product was more abundant. 600E cracking produces large amounts of ketones, benzene, phenol, indene and polycyclic aromatic hydrocarbons. The main pyrolysis products of 900e and 600E is similar, but the 900e of ketones, indene, polycyclic aromatic hydrocarbons 600E rich. (2) 300E, pH8.36 potassium citrate solution cleavage generates 2 aldehydes, 6 ketones, 1 kinds of fatty acids, so that the sample partial cracking; 600E, cracking to produce 20 aldehydes and ketones, 1 kinds of furan, aromatic benzene 2, 12, 8 kinds of phenols. Indene 14 kinds of polycyclic aromatic hydrocarbons in 27, a total of 84. 900e, there were 92 kinds of pyrolysis products, compared with 600E, an increase of 1 in benzene, 1 phenols, 4 indene, 2 kinds of polycyclic aromatic hydrocarbons, samples in 600E basic cracking completely, pyrolysis products more abundant 900e. (3) 300E, pH12.14 potassium citrate solution cleavage generates 2 aldehydes, 10 ketones, samples that partial cracking; 81 compounds were detected in 600e. Among them, 13 aldehydes and ketones, 1 kinds of furan, 1 aromatic benzene, 14 species, 6 kinds of phenols, indene 17 kinds, 29 kinds of polycyclic aromatic hydrocarbons. 86 compounds were detected under 900e. Among them, 16 aldehydes and ketones, 1 kinds of furan, 1 aromatic benzene, 14 species, 7 kinds of phenols, indene 18 kinds, 29 kinds of polycyclic aromatic hydrocarbons. The pyrolysis temperature increased from 300E to 600E, benzene, phenol, indene, polycyclic aromatic hydrocarbons increased dramatically in the pyrolysis products; while 900e compared with 600E, the pyrolysis products are basically the same type, so that the sample in 600E has been completely cracked. PH3.15,8.36,12.14 potassium citrate solution cracking, pyrolysis products of 300E were mainly aldehydes and ketones, indene and polycyclic aromatic hydrocarbons, the emergence of a large number of 600E at the same time, benzene and phenols increased dramatically, 900e type and 600E cleavage products base