Page:NIOSH Manual of Analytical Methods - 5046.pdf/2

 TETRAKIS(HYDROXYMETHYL)PHOSPHONIUM CHLORIDE: METHOD 5046, Issue 1, dated 15 March 2003 - Page 2 of 5

EQUIPMENT:

REAGENTS: 1. Formaldehyde-2,4-dinitrophenylhydrazone, (formaldehyde-DNPH ), 99% pure, Supelco, Bellefonte, PA, or Aldrich C hem ical Co., Milwa ukee, W I. 2. Tetrakis(hydroxymethyl)phosphonium chloride (THPC),* 80% aqueous solution. Aldrich Ch em ical Co., Milwauk ee, W I. NOTE: A sc ertain the correct p ercenta ge in solution by perform ing an assay [poten tiom etric titration of 0.22 g of 80% THPC solution (diluted with DI water and acidified with 10 mL of 25% sulfuric acid) with 0.1 M AgNO 3 and silver electrode] [1,8]. Density of 80% + 2% aqueous solution: 1.30 to 1.40 g/mL @ 20 oC. 3. Acetonitrile,* high purity solvent for HPLC ana lysis, low carbo nyl content. NOTE: Carbonyl content of acetonitrile can be determined by passing 10 mL of the solvent th rough a com m erically available cartridge containing silica gel coated with acidified DNPH and analyzing for formaldehyde-DNPH by HPLC. The concentration of formaldehyde-DNPH should be below the LOD. [2] 4. W ater, deionized (D I water). 5. Calibration stock solution. Accurately weigh 10 m g of form aldehyde-DN PH in a 10-m L volum etric flask. Add acetonitrile to the 10-m L mark. 6. Fortification stock solution, 10 mg/mL. Add 140 µL of 80% solution of THPC to 14.86 g of DI water.

1. Sa m plers, 37-m m, three-piece, plastic cas settes co ntaining two glass fiber filters, a front filter and a back up filter, separate d by 1 cm of sp ace by m ean s of a cen ter ca sse tte piece (spacer). Each filter is coated with 2 mg of acidified 2,4-dinitrophenylhydrazine (com m ercially available from SKC, E ighty Four, PA, as g lutaraldehyde sam pler, cata logue nu m ber 2 25-9 003 .* 2. Personal sampling pump, 1.0 to 1.7 L/min, with flexible connecting tubing. 3. Vials, 4 -m L, glas s, PT FE -lined ru bbe r sep ta in caps for airtight seals. 4. Liquid chrom atograph with UV detector, recorder, integrator, and colum n (p. 5046-1). 5. Syringes, 100-µL, 500-µL, and 10-mL. 6. Volumetric flasks, 25-mL, 10-mL. 7. W ater bath, 60 oC + 3 oC. 8. Syringe filters, PTFE mem brane, 0.45-µm porosity. 9. Forceps. 10. Equipment for NMAM 2016, Issue 2, for form aldehyde gas [2].

See SPECIAL PRECAUTIONS

SPECIAL PRECAUTIONS: On heating, THPC will decompose to form chlorine, amm onia, and oxides of phosph orus. Avoid high tem pera tures for T HP C and c onta ct with a lkalies or stro ng o xidizing a gen ts. THPC causes eye burns and moderate skin irritation. Dermal studies have shown that tetrakis(hydroxymethyl)phosphonium salts are promotors of skin cancer but not initiators. There was no evidence of carcinogenicity of THPC in rats and mice [4]. The liver is a target organ. DNPH is a suspect carcinogen and is light sensitive [7]. Acetonitrile is toxic and is a fire hazard (flash point = 12.8 oC).

SAMPLING: 1. Ca librate each personal sampling pump with a repres en tativ e sampler in line at the desired sampling rate. 2. Rem ove inlet cassette piece from sampler for open-faced sampling. Rem ove cap from outlet of sam pler. Open-faced sampling is recomm ended because excessive quantities of THPC will exha ust the qu antity of DNPH in a small area of the filter during closed-face sampling. 3. Attach sampler to the sampling pump with flexible tubing. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition