Development Of Headspace Gas Chromatographic Methods For The Determination Of Microbial And Toxic Substances’ Content In Paper Products

With the development of China’s paper making industry，the consumption of paperproducts is rising. Paper and paper products is widely used in our daily life. But generallyspeaking, the quality of our country’s paper products varies widely. Whther in large andmedium-sized or small enterprises, there are still many problems in areas of productionmanagement and quality control. For ensuring safety of consumers, the relevant department ofour state strengthened the supervision of the everyday consumer goods. The commonproblems of paper products are the bacteriological index, toxic or harmful substances(fluorescent whitening agent or formaldehyde) and physical properties. Therefore, establishthe convenient and fast methods for determination of paper products have great significancefor strengthening the supervision of the products，improving product quality and ensuringsafety of consumers.Firstly, this paper reports on a headspace gas chromatographic technique method forrapid determination of total bacterial counts and coliforms in paper products. In the presentmethod, the bacterial counts and coliforms in paper products can be determined within8hours and18hours. The present method is simple, accurate and much efficient compared withthe traditional method.Secondly, this paper reports on two headspace gas chromatographic methods for thedetermination of formaldehyde in paper products and formaldehyde related polymer latexes.These methods are based on the reaction of formaldehyde and sodium borohydride in alkalinesolution (a concentrated potassium carbonate solution (824g/L) or a sodium hydroxidesolution (1mol/L)), in which formaldehyde is quantitatively converted to methanol. Therepeatability of the method for paper products had a relative standard deviation of less than4.5%; the limit of quantification (LOQ) was7.7mg/kg, and the recovery ranged from96.8%–106%. The repeatability of the method for polymer latexes had a relative standard deviation ofless than5.0%; the limit of quantification (LOQ) was5.7mg/L, and the recovery ranged from96.2%–102%. The present method is simple, rapid, and accurate.Based on the hydrolysis of the pulp or paper matrix, we established a method fordetermination of methanol in paper products by headspace gas chromatography (HS-GC). Inthis method, ideal conditions is use a phosphoric acid solution(42.5%) as the medium at120°C in5h (excluding air contact) in order to release matrix-entrapped methanol, which isthen determined by HS-GC. Data show that, Reproducibility tests of the method generated a relative standard deviation of <3.5%, with recovery in the range of93.4%102%.Finally， this paper reports on a headspace gas chromatographic technique fordetermination of PEO in paper products. The PEO were converted to iodoethane inhydroiodic acid medium in a closed vial after sample extraction and concentration. Theiodoethane was then detected by headspace gas chromatography. The present method issimple, safety and high sensitivity compared with the traditional method.