GB2185572A

GB2185572A - Improvements in or relating to the chemical analysis of smoking related products

Info

Publication number: GB2185572A
Application number: GB08700697A
Authority: GB
Inventors: Terence Michael Long; Maurice Naylor; Susan Jane Alsop
Original assignee: IMP TOBACCO CO Ltd
Current assignee: IMP TOBACCO CO Ltd
Priority date: 1986-01-13
Filing date: 1987-01-13
Publication date: 1987-07-22
Also published as: GB8700697D0; GB8600682D0

Abstract

The glycerol triacetate content of a cellulose acetate cigarette filter rod is determined on a discrete analyzer by (a) preparing an extract solution of glycerol triacetate from a cellulose acetate filter, (b) reacting the extract solution with an alkaline solution of hydroxy ammonium chloride to provide a resultant reaction mixture of the two solutions, (c) reacting the resultant mixture of step (b) with an acid solution of ferric chloride, and, (d) measuring the concentration of ferric hydroxamate in the solution resulting from the reaction of step (c) at 500 nM, the concentration of ferric hydroxamate being proportional to the concentration of glycerol triacetate in the sample solution.

Description

SPECIFICATION Improvements in or relating to the chemical analysis of smoking related products This invention concerns improvements in or relating to the chemical analysis of smoking-related products, in particular cigarette filter rods made from cellulose acetate.

In the quality control of cigarettes orothersmoking articles it is customary to carry out chemical analyses of tobacco and other smoking-related products such as filter rod material and cigarette paper. These an- layses, include analyses for naturally occurring sugars and nicotine in tobacco, glycerol triacetate (triacetin) in cellulose acetate based filter rod material, and citrate salts, which are used as burn modifiers, in cigarette paper.

Hitherto, such analyses have been carried out by a number of laboratory personnel, each assigned to a separate analytical task. It is now proposed to carry out simultaneous chemical analyses of tobacco or tobacco-related products for a number of constituents by means of a discrete analyzer (one example of which being the Technicon RA-1000), such as is used in the clinical analysis of physiological samples, but adapted to carry out chemical analyses specific to the tobacco industry. The use of a discrete analyzer enables ana- lyres to be carried out simultaneously, more efficiently, more accurately, and more consistently, one one machine, than can be carried out by a number of separate analytical processes and operators.

There are restrictions imposed by the use of a discrete analyzer inherent in its nature, namely that itis unableto support heating, filtration, or dialysis procedures, the use of corrosive materials, or analysis cycles involving lengthy time delays. Although the discrete analyzer is designed to avoid cross-contamination, in practice this is difficult to achieve completely, and a consequence ofthis is that the chemical constitution of the reagents used must be such that interaction is minimal. Furthermore, discrete analysis is not a closed system and is open to airborne contamination.

Clearly, chemical analysis procedures hitherto used in the tobacco industry are generally unsuitablefor simultaneous use on a discrete analyzer and so must either be modified orcompletely changedto accommodate the new circumstances.

Triacetin is used as a plasticizer in the manufacture ofcellulose acetate filter rods, and is measured routinely as an aid to product development and quality control. The most common measurementtechnique is extraction by an alcohol, followed by gas chromatographic analysis. This technique is not possible onthe discrete analyzer, which demands a spectrophotometric analysis procedure.

According to the present invention there is provided a method of determining on a discrete analyzer the glycerol triacetate content of a cellulose acetate cigarette filter rod, the method comprising the steps of, (a) extracting the glycerol triacetate from a cellulose acetate filterto provide an extract solution, and, in the discrete analyzer, (b) reacting the extract solution with an alkylinesolution of hydroxy ammonium chloride to provide a resultant reaction mixture of the two solutions, (c) reacting the resultant mixture ofstep (b) with an acid solution offerricchloride, and, (d) measuring the concentration of ferric hydroxamate in the solution resulting from the reaction of step (c), the concentration of ferric hydroxamate being proportional to the concentration of glycerol triacetate in the sample solution.

The concentration of ferric hydroxamate may be measured spectrophotometrically at a wavelength of 500 nm.

The invention will now be described with reference to the following non-limiting example.

Three cellulose acetate ciga rette fi Iter tips were shaken for30 minutes in 25 ml of a 1:1 ethanol/water solution, and filtered to provide an extract solution A containing any glycerol triacetate that may have been presentinthefiltertips.

A reaction reagent B was prepared by dissolving 2.8 g hydroxy ammonium chloride (analytical reagent quality) and 1.8 g sodium hydroxide pellets (analytical reagentquality) in distilled water, making upto 250 ml with distilled water, and then adding 2 ml of a wetting agent (25% TRITON X-405, Trade Mark).

A reaction reagent Cwas prepared by dissolving 10 gferricchloride (analytical reagent quality) in 150 ml distilled water, transferring to a 200 ml graduated flaskwith 3 x 5 ml distilled waterwashings, adding 14ml concentrated sulphuric acid, making up to 200 ml with distilled water, and then adding 2 ml of a wetting agent (25%TRITON X-405,Trade Mark).

30 micro litres of extract solution Awere added to 275 microlitres of reagent B in a discrete analyzer. After3 minutes 45 seconds, 55 microlitres of reagent C were added to the reaction mixture of A and B. Afterthree minutes the formation of red ferric hydroxamate in the reaction mixture was monitored spectrophotometrically at a wavelength of 500 nm.

The same procedure was carried out on comparison glycerol triacetate solutions of known concentration.

The intensity of coloration of the red ferric hydroxamate complex is proportional to the concentrate of glycerol triacetate. Hence the concentration of glycerol triacetate in extract solution A is determined by comparison of the ferric hydroxamate readings with those of the comparison solutions.

Acomparison of the discrete analyzer method of the invention was made with a reference gaschromato graphy procedure on 6 cellulose acetate filter sample types. The results (mg triacetin/tip) were asfollows: Sample Type Gas Chromotography Discrete Analyzer 1 7.43 7.48 2 5.67 5.88 3 5.82 5.70 4 8.58 8.42 5 8.72 8.38 6 8.25 7.80 Statistical analysis showed a linear relationship: discrete analyzer = 0.97 x gas chromatography

Claims

1. A method of determining on a discrete analyzer the glycerol triacetate content of a cellulose acetate cigarette filter rod, the method comprising the steps of, (a) extracting the glycerol triacetate from a cellulose acetate filterto provide an extract solution, and, in the discrete analyzer, (b) reacting the extract solution with an alkaline solution of hydroxy ammonium chloride to provide a resultant reaction mixture of the two solutions, (c) reacting the resultant mixture of step (b) with an acid solution of ferric chloride, and, (d) measuring the concentration of ferric hydroxamate in the solution resulting from the reaction of step (c),the concentration of ferric hydroxamate being proportional to the concentration of glycerol triacetate in the sample solution.

2. The method as claimed in claim 1 wherein the concentration of ferric hydroxamate is measured spectrophotometrically at a wavelength of 500 nm.

3. A method of determining on a discrete analyzer the glycerol triacetate content of a cellulose acetate cigarette filter rod, substantially as hereinbefore described with reference to the example