Contents 1 PURPOSE 2 2 SCOPE 2 3 DEFINITIONS RESPONSIBILITY 3 5 PROCEDURE 3

Transcription

1 Contents 1 PURPOSE 2 2 SCOPE 2 3 DEFINITIONS RESPONSIBILITY 3 5 PROCEDURE Equipment & Apparatus Chemicals & Reagents Sample Preparation Screening Test on PVC (Beilstein Test) Sample Preparation for FTIR Quality Control Sample Preparation Instrumental Analysis Batch Sequence & Quality Control Acceptance Criteria Calculation Test report 11 6 FLOW CHART 12 7 ATTACHMENTS 13 8 APPLICABLE DOCUMENTS 13 9 QUALITY RECORDS 13 page 1 of 13

2 1 Purpose This test method is applicable to confirm the presence of PVC in plastic material and coating material by FT-IR 2 Scope This procedure is applicable to all Chemical Test Laboratories who responsible to conduct the PVC identification. Beilstein Test (Flame test) is performed on plastic material suspected to be PVC-based. The presence of PVC in plastic material will give a characteristic green flame (presence of halogen elements) in Flame Test. If a characteristic green flame is observed, PVC may be present in the plastic test material. The presence of PVC is further confirmed by using Fourier Transform Infrared Spectrophotometer (FTIR). 3 Definitions Term/Acronym FTIR CAS PP PVC THF mg g min hr ml mm cm Definition Fourier Transform Infrared Spectrophotometer Chemical Abstract Service Polypropylene Polyvinyl Chloride Tetrahydrofuran Milligram Gram minute Hour Milliliter Millimeter Centimeter page 2 of 13

3 4 Responsibility All managers of Chemical Laboratories who perform this test are responsible to ensure that this procedure is followed by their laboratory. It is the responsibility of the Author to ensure that the procedure is reviewed and updated as and when required. 5 Procedure 5.1 Equipment & Apparatus Bunsen burner Copper wire Microscopic slide Paper thimble Soxhlet extractor FT-IR or equivalent Petri dish Hot plate Lighter Test tube Forcep Blade Heater Glass container page 3 of 13

4 5.2 Chemicals & Reagents Tetrahydrofuran, CAS # Diethyl ether, CAS # Dichloromethane, CAS # Hexane, CAS # Concentrated Sulphuric acid, CAS # PVC negative laboratory control sample polymer confirmed to be free of PVC from the local laboratories PVC positive laboratory control sample polymer confirmed to contain trace amount (~10-20% PVC) of PVC from the local laboratories Preparation of 10% PVC controlled sample Mix 0.9g PP powder and 0.1g PVC powder thoroughly in a small glass container (5.1.14) Transfer around 0.2g of mixed powder on a microscopic slide (5.1.3) Put the slide on a pre-heated heater (5.1.13) and cover the powder with another microscopic slide (5.1.3) Let the powder to melt Use a forcep (5.1.11) to press against the top slide firmly during the melting process until a transparent thin film is formed from the melted powder Cool down the slides Use a blade (5.1.12) to gently peel off the thin film from the slide for PVC analysis. page 4 of 13

5 5.3 Sample Preparation Take sample randomly or based on specific Customer request. For complex sample, pictures of the sample must be taken after marking the sampling sites. 5.4 Screening Test on PVC Beilstein Test (Flame Test) Heat a copper wire (5.1.2) until red in blue flame region of a Bunsen burner (5.1.1) Bring the heated wire in contact with test material and let some test material adhere to the copper wire Bring the copper wire with test material to the blue flame region of a Bunsen burner (5.1.1) Observe the flame color on ignition of the test material against a white background Record the flame color If the result is positive (A distinct green/blue-green color observed), the presence of PVC would be confirmed by FTIR in accordance with section 5.5. page 5 of 13

6 5.5 Sample preparation for FTIR Bulk and Rigid Plastic Materials (Without a flat surface) Place a portion of sample in between 2 microscopic slides (5.1.3) Hold the slides horizontally and press the sample against the slides Apply heat by using a lighter (5.1.9) or hot plate (5.1.8) to the lower slide Allow the sample to melt Before the sample is re-solidified, press against the slides to form a film Hold the slides in place until they cool down Peel the film off from the microscopic slide when the film is dry Soft plastic material/material with a flat surface Cut the sample into strip with surface area of 110mm² x 20 mm 2 for FT-IR (5.1.6) analysis Plastic material which is suspected to be PVC-based For sample which is suspected to be PVC-based, i.e. after confirmation of characteristic green flame in flame test (5.4.1), the plasticizer from test sample is removed for a better spectrum Cut 2g - 3g of sample into pieces with dimension of 2mm x 2mm x 2mm (For sample which can be analyzed with FTIR, cut the sample into strip with surface area of 110mm² x 20 mm 2 instead Place the sample into paper thimble (5.1.4) Remove plasticizer from the sample by Soxhlet extraction with diethyl ether (5.2.2) for at least 4 hr Empty the sample in extraction thimble into a Petri dish (5.1.7) Allow the sample to be air-dried For strip of sample and sample after removal of plasticizer can be analyzed with FTIR directly. page 6 of 13

7 For sample not suitable for direct FTIR analysis, dissolve it with minimum amount (5ml) of Tetrahydrofuran (THF) (5.2.1). Note: For samples of printing on shell fabric or plastic, filtration or centrifuge might be necessary so as to remove interfering substances in the THF ( ) Evaporate few ml of the solution with a few drops at a time on a microscopic slide (5.1.3) Accelerate drying with gentle heating Peel the film off from the microscopic slide when the film is dry. Note: For samples of printing on shell fabric or plastic materials constituting more than one kind of polymer (e.g. co-polymer), IR characteristics of PVC might be masked by that of other plastics. If this sample contains PVC, the result of Beilstein test would be positive, while result of FT-IR test would be negative. (Refer to Figure 1 for an example of IR spectrum that signal of PVC at 600 cm cm -1 is masked) If the characteristic peaks of the PVC spectrum is masked. Retest the samples by following procedures page 7 of 13

8 Removal of interference Removal of plastizicer Dissolve the 1g sample with 10ml THF (5.2.1) Add 20ml hexane (5.2.4) to the THF solution for the precipitation Filter the precipitate by filter paper and wash the precipitate with THF (5.2.1) Dry the sample at room temperature Examine the precipitate by following the procedure 5.5.1, or Removal of interference of polyurethane Weigh 1g sample into a test tube Dissolve the sample with 10ml concentrated sulphuric acid (5.2.5) for 30 minutes and stir occasionally Discard the acid and collect the residues in the test tube Wash the residue with water and let it dry at room temperature Examine the residue by following the procedure 5.5.1, or page 8 of 13

9 5.6 Quality Control Sample Preparation Prepare negative laboratory control sample by repeating clause 5.4 to Prepare positive laboratory control sample by repeating clause 5.4 to Proceed to clause 5.7 for FTIR analysis Note: The laboratory shall verify the sensitivity of the FT-IR to detect 10% or lower PVC in polymer sample. 5.7 Instrumental analysis Collect a spectrum for sample prepared from 5.5 and Match the spectrum of sample with compound in hit list Characteristic major and minor absorption bands of PVC (Figure 1: Spectrum of PVC) 1. Broad band between 600 cm cm Strong peaks at 1250 cm -1 and 1330 cm Strong peak at 1430 cm Double peaks at 2900 cm -1. Note: A carbonyl band will be present at 1742 cm -1 if it is a copolymer of vinyl chloride and vinyl acetate, but this may be arose from incomplete extraction of certain polymer ester plasticizers page 9 of 13

10 Figure 1: FTIR Spectrum of Polyvinyl Chloride (PVC) The presence of PVC shall be confirmed if the characteristic major and minor absorption bands shown in are present Enter the results in the raw-data sheet. Note: For other brands of equipments, Lab can follow a suitable equipment conditions with proper resolution and response of analytes in matrix with appropriate run time in reference to the conditions mentioned as above. 5.8 Batch Sequence & Quality Control Acceptance Criteria S. No QC Point Criteria Batch 1 PVC negative laboratory control No PVC should be detected 1/10 sample (5.2.5) 2 PVC positive laboratory control PVC should be detected 1/10 sample (5.2.6) 3 Samples 1 to 10 with Duplicates Consistency within duplicates 1/10 page 10 of 13

11 5.9 Calculation Determine the presence of PVC in the tested sample by the criteria as stated in to Limit of Detection: 10% Test report The test report shall contain at least the following information: Test Standard number Origin and Destination of the sample (if applicable) Type and identification of the product and/or material tested Date of receipt and date of analysis Sampling procedure (if applicable) Detection Technique Any deviation in agreement or otherwise from the test Any unusual features observed during the determination page 11 of 13

12 6 Flow Chart Flow Chart - PVC Determination Plastic Sample PVC Screening Test Positive? No Yes Sample preparation for bulk & rigid plastic material Sample preparation for soft plastic material / material with a flat surface Sample preparation for material which is suspected to be PVC-based FT-IR spectrum Collection Identify characteristic peaks and/or bands from the spectrum PVC positive? Yes Confirm the fail results No Fail Pass Submit the Raw Data sheet page 12 of 13 Preparation & Review of Test

13 7 Attachments Not Applicable 8 Applicable Documents Sadtler IR Database Basic Monomers & Polymers Vol. 1 (Unmodified) or equivalent. Tables of Spectral data for structure Determination of Organic Compounds 13C-NMR 1H-NMR IR MS UV/Vis Chemical Laboratory Practice, 2 nd Ed, Springer-Verlag 9 Quality Records Positive and negative control records Test report (s) generated as per this procedure. page 13 of 13