Title of Invention

"A PROCESS FOR THE DETERMENATION OF VOLATILE SUBSTANCES IN EDIBLES".

Abstract

This invention relates to a process for the estimation of volatile substance. According to the process the distilled water is heated in a flask to a first temperature. The sample to be tested is added into the heated water and the flask is closed. The flask containing the sample is maintained at a second temperature lower than the first temperature. The flask is purged with air and the volatile vapours are drawn and subjected to the steps of analysis.

Full Text

FIELD OF INVENTION This invention relates to an improved process for estimation of volatile substance as herein before described. Such volatile substances can, for example, be flavors and volatile pollutants in edible matter. BACKGROUND OF THE INVENTION. There is fixed permissible limit for bacterial/microbial count in the food stuff. To keep microbial count below the limit, food material is treated with bleaching powder/chlorine water, which leads to the generation of chloroform residues. Since chloroform is a carcinogen, European countries have fixed its Maximum Residue Limit (MRL) 100 ppb in the food stuff. There are two major techniques, which have been described in the literature for the determination of chloroform residues in the food stuff. Purge and trap method in which chloroform residues from food were trapped in resin, from which it was later eluted and estimated. Such a process requires high cost resin and ultra pure solvents in addition to costly apparatus. Another method known in the art, is the headspace method and in which vapours are drawn from the headspace of a septum-sealed vial containing a sample to be analysed. The vial was then heated to drive out dissolved organics out of solution and into the vapour headspace (Ward; Clydie, US Patent Application no. 301385 dated April 27, 1999; US patent: 6,286,375). In another method, the vial containing volatile sample was heated by Green et al 2000 and agitated to enhance a transport rate of the volatile sample from material to the headspace of the vial (United States patent 6,146,895, November 14, 2000). For extraction Ray, et al., 1997 proposed extractor having sample chamber pressurizable either by gas or mechanical means. The sample chamber was construed with removable liner of poly tetrafluorethylene (United States Patent 5,607,234 March 4, 1997). Augenblick et al. 1994 describes yet another method and apparatus for collecting gases from the sample headspace of sealed container. Gas sample from the headspace to instrument was carried by carrier gas (United State Patent no. 5,363,707 dated November 15, 1994). Vibration used to promote the formation of sample gas. Main drawbacks of these aforesaid processes:- 1. Heating of vessel containing sample cause development of high pressure inside which can cause explosion and injuries. 2. Additional carrier gas is required, which increase the cost of analysis. 3. Additional instruments like vibrator required, which increase the cost of analysis. 4. Small size vials were used, which are unable to accommodate large size sample. 5. Bags were used which can break at high temperature and pressure. 6. High cost of analysis per sample. 7. High capital cost. 8. Danger of breakdown of labile compounds at prolonged high temperature and therefore lower estimation. OBJECT OF THE INVENTION An object of this invention is to propose a process for the estimation of volatile substances. Another object of this invention is to propose a process for the estimation of volatile substances, which obviates the disadvantages associated with those of the prior art. Yet another object of this invention is to propose a process for the estimation of volatile substances and wherein chloroform residues are released from the sample into headspace under partial vacuum or at low pressure whereby reducing risk of leakage of volatile substances. Still another object of this invention is to propose a process for the estimation of volatile substances and wherein no additional carrier gas is required. A further object of this invention is to propose a process for the estimation of volatile substances and wherein prolonged high temperature is not required. A still further object of this invention is to propose a process for the estimation of volatile substances, which involves low cost of apparatus. DESCRIPTION OF INVENTION According to this invention there is provided an improved process for estimation of volatile substance as herein before described comprises in the steps of: i) heating distilled water in a flask at 100° C at a atmospheric pressure, ii) adding the sample of any edible to be tested into said heated water, iii) closing the flask, iv) maintaining the flask containing the sample at a second temperature of 45°C to create low pressure or vacuum, v) purging with air, vi) drawing the volatile vapours and subjecting it to analysis for qualitative and quantitative determination in conventional manner. Further according to this invention there is provided an apparatus for estimation of thermolabile highly volatile substances as claimed in claim 1 comprising a flask 1, neck 2 having a stopper 3 adapted to fit and close the mouth 4 of said flask 1, a closure member for closing the mouth 4 of said stopper 3, characterised in that is a stopper. In accordance with this invention, distilled water is heated to a first temperature under atmospheric conditions. Such a first temperature can, for example, be the boiling temperature of water. Thereafter, the flask is removed from the heat source and the sample to be analyzed is introduced into said flask and then maintained at a second temperature lower than said first temperature. However, after introducing the sample into said flask, the flask is closed. As the flask is in a closed status and the temperature reduced from a first to a second temperature, a vacuum or low pressure is created within said flask. By way of example and without implying any limitation thereto, the first temperature is the boiling temperature of water and the second temperature is approximately 45°C. The flask is maintained at the second temperature for approximately 45 minutes. Thereafter, the vacuum is broken by purging air into the flask Turbulence is caused within said vessel so as to disperse the volatile substances in the head space within the closed flask. A sample is removed from the headspace and analyzed. Preferably the sample is wrapped in a foil and introduced into the flask. Several distinct advantages ensue by the present advantages. As the sample is added to boiling water, there is flask heating and not sustained heating, and whereby decomposition of the sample is prevented and formation of undesirable compounds avoided. It has been found that water can also be heated to a temperature lower than the boiling temperature. However, the second temperature would then need to be adjusted. Primarily, the first and second temperature is to provide a reduced pressure or vacuum within the closed vessel, as a volatilization is more effective at a reduced pressure or vacuum. In the known art, volatilization was less effective as it was carried out at high pressure. Thus, the present invention is based on the fact that volatile compounds released from the plant matrix under reduced pressure. Released volatile compounds accumulate in the headspace from where they can be collected and analysed. Further more it has been found that equilibration of closed container, containing sample in vacuum, at a constant temperature was important for the reproducibility of results. Thus according to one aspect of the present invention there is closed container containing sample/volatile material and water. Sample is added prior to closure of the container. Examples of closed containers which may be useful in accordance with invention include glass flask (250 ml) with B-24 neck, this flask is attached with 7 cm stopper having B-24 joint at one end and 1.5 cm diameter hole at the top closed by a 2 cm silicon cork. The volatile substance may in general comprise of flavours present in food, beverages and other additives. However, other volatile contaminants like halogens can be estimated too. Boiling of water prior to adding sample expel the air inside the flask and when temperature of flask is lowered vacuum is created which causes the release of volatile substances from the plant matrix. Thus the processes involving introduction of plant matrix/sample into the boiled water and equilibrating at a constant temperature followed by introduction of air, is the point of completion of the treatment. Working examples: Example-I Weigh 1 g crop material into a aluminiun foil and fold loosely in a packet form so that crop material could easily come in contact with the water, after its insertion into the flask. First take thirty milliliter distilled water in 250 ml flask, boil then replace flask from the heat source, push in the packet containing the material and immediately encap with stopper (stopper plugged with silicon cork). Swirl the flask until material from the aluminium foil come in the contact with the warm water. Equilibrate the flask at 40°C for one hour in the incubator. At the end, insert needle of 10 ml syringe through the silicon cork and introduce air into it for 30 seconds. Replace the plunger, move plunger up and down three times. Then suck 10 ml vapours from the flask into the syringe and then take out the syringe. Out of 10 ml vapours expel 9 ml and inject remaining vapours into gas chromatograph fitted with BCD and capillary column for qualitative and quantitative estimation. Example-H Step I Take 0.1 ml chloroform (ca. 140 mg) in 10 ml methanol which will give strength of ca. 14000 parts per million (ppm). Step II Take 1 ml of step I solution in 100 ml of water whose strength will be equivalent to ca. 14000 parts per billion (ppb). Step III(Table Removed)Step IV Take 0.1 ml working solution as per Step III column 3 of the above table and fill it in the disposable dispenser's tip. Step V Insert the filled tip into the flask after removing the flask (containing water) from the heat source. Step VI Immediately encap the flask with the glass stopper containing silicon cork at the top. Equilibrate the flask at 40°C for one hour in the incubator. At the end, insert needle of 10 ml syringe through the silicon cork and introduce air into it for 30 seconds. Replace the plunger, move plunger up and down three times. Then suck 10 ml vapours from the flask into the syringe and then take out the syringe. Out of 10 ml vapours expel 9 ml and inject remaining vapours into gas chromatograph fitted with capillary column (0.35 jo. and 35 m long) for qualitative and quantitative estimation. Keep oven, injection port and detector temperature at 70°C, 100°C and 300°C, respectively. Under these conditions minimum detection limit for chloroform is 5 ppb. DESCRIPTION WITH REFERENCE TO DRAWINGS Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawing, which illustrates an exploded view of the flask of the present invention. The flask 1 has a neck 2. A stopper 3 is adapted to close the mouth 4 of flask 1. Stopper 3 has a lower section 5, which is a conical member and an upper frusto conical section 6. Mouth 7 is adapted to be closed by a closure 8. WE CLAIM; 1. An improved process for estimation of volatile substance as herein before described comprises in the steps of: i) heating distilled water in a flask at 100° C at a atmospheric pressure, ii) adding the sample of any edible to be tested into said heated water, iii) closing the flask, iv) maintaining the flask containing the sample at a second temperature of 45°C to create low pressure or vacuum, v) purging with air, vi) drawing the volatile vapours and subjecting it to analysis for qualitative and quantitative-determination in conventional manner. 2. An improved process for estimation of thermolabile highly volatile substances substantially as herein described and illustrated. 3. An apparatus for estimation of thermolabile highly volatile substances as claimed in claim 1 comprising a flask 1, neck 2 having a stopper 3 adapted to fit and close the mouth 4 of said flask 1, a closure member for closing the mouth 4 of said stopper 3, characterised in that is a stopper 3. 4. An apparatus as claimed in claim 7 wherein said stopper 3 is a hollow member. 5. An apparatus as claimed in claim 7 wherein said stopper 3 comprises a lower section 5 of a conical section and an upper section 6 of a frusto conical section. 6. An apparatus for estimation of thermolabile highty volatile substances substantially as herein described and illustrated.

Documents:

844-del-2002-abstract.pdf

844-del-2002-claims.pdf

844-del-2002-correspondence-others.pdf

844-del-2002-correspondence-po.pdf

844-del-2002-description (complete).pdf

844-del-2002-drawings.pdf

844-del-2002-form-1.pdf

844-del-2002-form-19.pdf

844-del-2002-form-2..pdf

844-del-2002-form-3.pdf

844-del-2002-gpa.pdf

844-del-2002-petition-124.pdf