BS ISO 16000-3 pdf download – Indoor air Part 3: Determination of formaldehyde andother carbonyl compounds in indoor air andtest chamber air — Active sampling method.
6.2 Sample preparation
62.1 Cartridge containers. eg. borosilicate glass culture tubes (20 mm V 125 mm) with polypropylene screw caps, or other suitable containers, to transport coated cartridges.
62.2 PolyeThylene gloves, to handle silica gal cartridges.
6.2.3 Transportation containers. lncbon-top metal cans (e.g. of volume 4 I) or other suitable containers. wth polyethylene air-bubble packing or other suitable padding, to hold and cushion the sealed cartridge containers.
NOTE A heal-sealable roil-lined plastic pouch of the type included with some cocimercist pre-coated DNPH cartfldges can be used for storing a DNPH-coatd cartridge after sampbg, If appropriate
6.2.4 Support for coating cartridges. A synnge rack, made from an aluminium plate (0.16 cm V 36cm *53cm) with adjustable legs on four corners. A matrix (5*9) of circular holes of diameter slightly larger than the diameter of the 10 ml syringes, symmetrically dflhled from the centre of the plate, to enable batch processing of 45 cartridges for cleaning, coating and/or sample elution (see Figure 3).
6.2.5 Cartridge-drying manifold, such as a support with gas connectors and with multiple standard male syringe connectors (see Figure 3).
NOTE The apparatus specified in 6.2.4 and 6.2.5 is needed only if users choose to make their own DNPI’l-coated
6.3 Sample anatyss
6.3.1 HPLC system, consisting of:
a) a mobile phase reservoir with an outgassing device (e.g. membrane under reduced pressure);
b) a high-pressure pump;
c) an injection valve (automatic sampler with a 25 p1 or other convenient loop volume);
d) a C-18 reverse phase (RP) column (e.g. 25cm V 4.6 mm inside diameter. 5 pm particle size);
e) a Liv detector or diode array detector operating at 360 nm.
f) a data system or strip chart recorder.
The DNPH-forrnaldehyde derivative is determined using socratic reverse phase HPLC, equipped with an ultraviolet (IJV) absorption detector operated at 360 nni. A blank cartridge is likewise desorbed and analysed. Formaldehyde and other carbonyl compounds in the sample are identilied and quantified by comparison of their retention times and peak heights or peak areas with those of standard solutions
NOTE I Most commercial HPLC analytical systems are adequate for this application.
NOTE 2 A cokeiin oven can be used to assure constant column operating temperature and improve reproducibility
6.3.2 Syringes and pipetles
6.3.2.1 HPLC injection syringes, with capacity at least four times the loop volume (see 6.3.1).
6.3.2.2 Syringes, volume 10 ml, used to prepare DNPH-coated cartridges (polypropylene syringes are adequate).
6,3.2,3 Syringe fittings and plugs, to connect cartridges to the sampling system and to cap prepared cartridges
6.3.2.4 Pipettes, positive-displacement, repetitive-dispensing type, with capacities in the O ml to l0 ml range. ISO 8655-2.
8 Preparation of reagents and cartridges
8.1 Purification of 2,4-dinitrophenylhydrazine
Formaldehyde contamination of the DNPH reagent is a frequently encountered problem. The DNPH (7.1) shall be punfied by multiple recrystallizations In UV-grade acetonitnle (7.2). Recrystallization is accomplished, at 40 C to 60 C, by slow evaporation of the solvent to maximize crystal size, lmpuflty levels of carbonyl compounds Ni the DNPH are determined prior to use by HPLC and should be less than 0.15 pg per cartfldge and per indrvidual compound.
Prepare a supersaturated solution of DNPH by boiling excess DNPH In 200 ml of acetonitrile for approximately I h. After 1 h. remove and transfer the supematant to a covered beaker on a hof plate and allow gradual cooling to 40 °c to 60 °C. Maintain the solution at this temperature (40 °C) until 95 % volume fraction of solvent has evaporated Decant the solution to waste, and nnse the remaining crystals twice with three times their apparent volume of acetonitnle. Transfer the crystals to another dean beaker, add 200 ml of acetonitnie, heat to boiling, and again let crystals grow slowly at 40 c to 60 t until 95 % volume fraction of the solvent has evaporated. Repeat the rinsing process as specified above. Take an aliquot of the second rinse, dilute 10 times with acetonetrile, acidify with 1 ml of 3.8 molfl perchlonc acid (7.3) per 100 ml of DNPH solution, and analyse by HPLC. in accordance with 9.3.4.
WARNING — Carry out this procedure under a property ventilated hood and behind an explosion shield
MOTE An acid is necessary to catalyse the reaction of carbonyl compounds with DNPH. Most strong inorgarac acids such as hy&octdoric. nMuric, phosphoric or perchlortc scads pertorm satisfactordy. In rare cases. hy&ochloric and sulfuric acids cause problems.
An acceptable impurity level is <0.025 pgiml of formaldehyde hydrazone in recrystallized DNP’H reagent or 0.02 % mass fraction of the DNPH.
BS ISO 16000-3 pdf download – Indoor air Part 3: Determination of formaldehyde andother carbonyl compounds in indoor air andtest chamber air — Active sampling method
