BS ISO 14382:2012 pdf download
BS ISO 14382:2012 pdf download.Workplace atmospheres -Determination of toluene diisocyanate vapours using1-(2-pyridyl) piperazine-coated glass fibre filters and analysis by high performance liquid chromatography with ultraviolet and fluorescence detectors.
All dilutions of the stock solutions are made to arrive at the working range in 90 + 10 parts by volume ACN + OMSO. For example, a stock standard prepared in DMSO can be diluted 1-.10 with pure ACN to arrive at 90 • 10 parts by volume ACN + I)MSO. Any further dilutions are made with 90. 10 parts by volume ACN + DMSO,
5.2.2 Preparation of analytical standards using pure TDI
Analytical standard solutions can also be prepared by reacting Tt)l (either pure 2,4-TDI or pure 2,6-TIN isomer) wIth 1-2PP In solution. Prepare a solution containing I mg/mi (0,006 mmol/l) 1-2PP by diluting 100 rng of 1-2PP to the mark with 90 + 10 parts by volume ACN + DMSO in a 100 ml volumetric flask, ISO 1042,l’l class A. Prepare a separate solution of 1 mg/mI (0,006 mmol/l) pure TDI by carefully and accurately weighing SO mg of TDI (to three significant figures) and diluting it to the mark with 90 + 10 parts by volume ACN + DMSO in a 50 ml volumetric Ilask. Pipette 1 ml to 3 ml of the 1 mg/mI TDI solution into a 25 ml volumetric flask and dilute to the mark with the 1 mg/mI 1-2PP solution. Mix the solution well and allow It to react ovrnighL Do not use more than 3 ml of the TDI solution In order to ensure a proper excess of 1-2PP. Do not use the conversion factor in 5.2.1 to calculate the concentration of these standards. Use fresh solutions. The amount of pure TIN isomer shall be accurately known to prepare accurate standards.
5.2.3 Commercial standard solutions
Analytical standard solutions are commercially available.
5.3 Filter extraction solution
This solution is composed of 90 • 10 parts by volume ACN • DMSO.
5.4 l-2PP filter coating solution
This solution Is composed of 4 mg/mI (0,025 mmol/l) 1-2PP in methylene chloride.
5.5 HPL,C mobile phase
This solution is composed of 0,01 M ammonium acetate (buffered to p11 6,2 with acetic acid) in water and acetonitrile. The exact composition of the mobile phase depends on the HPLC column selected for use. The buffered ammonium acetate solution can be prepared separately and used in a solvent programmed gradient with acetonitrile.
6 Apparatus
6.1 Air sampler
The air sampler consists of a three piece 37 mm polystyrene cassette with a glass fibre filter (type A/E binder free) coated with 2 mg of l-2PP (see Figure 1).
6.1.1 Preparation of coated filters
Prepare a sufficient volume of a solution containing 4 mg/mI i-2PP in methylene chloride. The volume is based on the number of filters to be coated. Use 0,5 ml of this solution to coat each filter. Use a properly functioning fume hood to evaporate the solvent and minimize exposure of the filters to light during coating, drying, and subsequent operations. Separately place the uncoated glass fibre filters on a nickel-chromium wire grid or on the rims of 40 ml glass beakers so that only the edges of the filter are supported. Carefully, and slowly, pipette 0,5 ml of the 1-2P1’ solution onto the centre of the filter. This volume of solution is sufficient to fully wet the filter. Allow the methylene chloride solvent to evaporate in the hood for about lii. Transfer the coated filters to a clean dry container, loosely cap the container, and place the container in a vacuum desiccator equipped with a cold trap, Further dry the filters at reduced pressure for about 2 h. Analyse at least three of the coated filters for TDI after they are dry and store the remaining filters in a closed container in a freezer at —20 °C. There are various recommendations for the shell life of these filters, however, they have been successfully used for up to 1 year after preparation when stored in a freezer until use. Do not store isocyanates. anhydrides. -alcohols, carhoxylic acids, or arnines in the same freezer.
6.1.2 CommercIal coated filters
Glass fibre filters coated with 1-2PP are commercially available; however, the amount of 1-2PP coated on
the fllter may be different than specified in this International Standard.
6.1.3 Assembly of sampling cassettes
Store the costed filters and assembled cassettes in a freezer. Do not store Isocyanates. anhydrides. alcohols, carboxylic acids, or amines in the same freezer.
Try to anticipate sampling needs and to minimize storage time for assembled sampling cassettes.
Place a cellulose spacer ring on the cassette bottom, then put a coated filter on top of the spacer ring, and place a cassette ring on top of the coated filter. Use sufficient pressure to completely seal the assembled sampling cassette. Seal the cassette with a shrink band. Sampling is performed with an open-face cassette; therefore, the cassette top need not he firmly attached to the sampler unless the assembled sampler Is to be stored where it could become contaminated or If It Is to be stored for more than I day or 2 days before use.
6.2 Sampling pump
The pump shall fulfil the requirements of EN 1232(l or equivalent. The sampling pump shall be capable of maintaining a flow rate of (1,00 t 0,05) 1/mm with the air sampler in-line.
