Answer to Question #88701 in General Chemistry for tia

Question

Acetone, a ketone, is a good solvent. It is commonly used as nail polish remover, paint thinner and remover. As a result, acetone could be a significant indoor air pollutant. Check the open literature and suggest a monitoring method for acetone in indoor or ambient atmosphere. Describe the measurement principle of the monitoring method. Please indicate your source of information.

Answer 1

Acetone, a ketone, is a good solvent. It is commonly used as nail polish remover, paint thinner and remover. As a result, acetone could be a significant indoor air pollutant. Check the open literature and suggest a monitoring method for acetone in indoor or ambient atmosphere. Describe the measurement principle of the monitoring method. Please indicate your source of information.

Solution:

The monitoring methods for acetone in indoor or ambient atmosphere:

1.Reference Methods. In general, standard air monitoring methods for acetone are based on liquid impinger, coated-solid cartridge, sorbent tube, or direct-reading instrument sampling approaches. Widely employed and accepted reference air monitoring methods for acetone have been developed, tested and reported by the United States Environmental Protection Agency (US EPA), the National Institute of Occupational Safety and Health (NIOSH), and the Occupational Safety and Health Administration (OSHA). 

2.US EPA Compendium Method TO-5.The US EPA has developed a number of methodologies suitable for sampling ambient air for trace-level concentrations of acetone. US EPA Compendium Method TO-5 describes the determination of individual aldehydes and ketones (including acetone) in ambient air using liquid impinger sampling followed by high performance liquid chromatography (HPLC) analysis with an ultraviolet (UV) detector (US EPA, 1999). Advantages of this method include: specific for aldehydes and ketones, good stability for derivative compounds formed in the impingers and low detection limits (i.e., 1-50 ppbv). Disadvantages of this method include: acetone laboratory contamination is common, sensitivity limited by reagent purity, potential for evaporation of liquid over long term sampling, and isomeric aldehydes and ketones may be unresolved by the HPLC system.

3.US EPA Compendium Method TO-11A .The US EPA Compendium Method TO-11A describes the determination of formaldehyde and other carbonyl compounds (including acetone) in ambient air utilizing a DNPH coated-solid adsorbent followed by analysis with HPLC/UV detection (US EPA, 1999). The procedure is similar to US EPA Compendium Method TO-5 except that a coated silica gel cartridge is used instead of a liquid impinger. The advantages of this method include: placement of sorbent as first element in the sampling train minimizes contamination, sampling system is portable and lightweight, large database, and proven technology. Disadvantages of this method include: isometric aldehydes and ketones and other compounds with the same HPLC retention time may interfere, liquid water captured on the DNPH cartridge during sampling may interfere, carbonyls Assessment Report on Acetone for Developing Ambient Air Quality Objectives 26 on the DNPH cartridge may degrade if an ozone denuder is not employed, and ozone and UV light deteriorates trapped carbonyls on cartridge. 

4.US EPA Compendium Method TO-17. The US EPA Compendium Method TO-17 describes the determination of volatile organic compounds (VOCs) (including acetone) in ambient air using active sampling onto sorbent tubes (US EPA, 1999). This method is an alternative to the liquid impinger sampling method presented in Compendium Method TO-5 and to the coated-solid cartridge method presented in Compendium Method TO-11A. The advantages of this method include: placement of the sorbent as the first element minimizes contamination from other sample train components, large selection of sorbents to match with target analyte list, includes polar VOCs, better water management using hydrophobic sorbents, large database and proven technology, and size and cost advantages in sampling equipment. Disadvantages of this method include: distributed volume pairs required for quality assurance, rigorous clean-up of sorbent required, no possibility of multiple analysis, must purchase thermal desorption unit for analysis, desorption of some VOCs is difficult, and contamination of adsorbent can be a problem. 

5.US EPA Method 0030. The US EPA has also developed a method suitable for sampling gaseous emissions from a wide variety of stationary sources for the determination of trace-level concentrations of acetone. US EPA Method 0030 - Volatile Organic Sampling Train (VOST) describes the methodology for the collection of volatile principle organic hazardous constituents (POHCs) (including acetone) from Assessment Report on Acetone for Developing Ambient Air Quality Objectives 27 the stack gas effluents of hazardous waste incinerators (US EPA, 1986). For the purpose of definition, volatile POHCs are those POHCs with boiling points less than 100o C. This method employs a 20 L sample of effluent gas containing volatile POHCs that is withdrawn from a gaseous effluent source at a flow rate of 1 L/min, using a glass-lined probe and a VOST. 

6.NIOSH Method 1300.The NIOSH to determine acetone in air (NIOSH Method 1300) consists of collecting acetone on charcoal adsorption tubes with subsequent chemical analysis by gas chromatography with flame ionization detection (GC/FID) (NIOSH, 1994). Sampling is conducted by drawing air through a solid sorbent tube (coconut shell charcoal, 100 mg in the front section and 50 mg in the back section) using a personal sampling pump. The suggested flow rate is 0.01 to 0.2 L/min and the minimum volume collected should be 0.5 L and the maximum 3 L. The contents of the tube are desorbed with carbon disulphide and the desorbate is analyzed by GC/FID. The level of detection for concentrations of acetone using this method is 0.007 mg/L.

7.NIOSH Method 2549. The NIOSH to determine acetone in air (NIOSH Method 2549) consists of collecting acetone in thermal desorption tubes with subsequent chemical analysis by GC/MS (NIOSH, 1996). Sampling is conducted by drawing air through a thermal desorption tube (i.e., a multi-bed sorbent tube containing graphitized carbons and carbon molecular sieve sorbents) using a personal sampling pump. The suggested flow rate for acetone is 0.02 L/min with a volume collected of 5 L. The contents of the tube are thermally desorbed and the desorbate is analyzed by GC/MS. The level of detection for concentrations of acetone using this method is 100 ng or less.  

8.NIOSH Method 3800. The NIOSH to determine acetone in air (NIOSH Method 3800) consists of detecting concentrations of acetone using a portable direct-reading instrument using extractive Fourier Transform Infrared (FTIR) spectrometry (NIOSH, 2002). Sampling is conducted by drawing air through the instrument using a sampling pump at a flow rate of is Assessment Report on Acetone for Developing Ambient Air Quality Objectives 28 0.1 L/min to 20 L/min. The air is subsequently analyzed via FTIR spectrometry and the results displayed. The level of detection for concentrations of acetone using this method with a path length of 10 m is 0.95 ppmv with a maximum detectable concentration of 148 ppmv.

9.OSHA Method 69.OSHA has developed a fully validated method for the determination of acetone that is suitable for occupational, personal and area monitoring. The current methodology used by the OSHA to determine acetone in air (OSHA Method 39) was developed to be rapid, sensitive and precise (OSHA, 1988). This method consists of collecting acetone by drawing a known volume of air through standard sized sampling tubes (containing 130 mg of a carbon based molecular sieve absorbent in the front section and 65 mg in the back section) using a personal sampling pump. The suggested flow rate is 0.05 L/min and the recommended volume collected is 3 L after a sampling time of 1 hour. Samples are desorbed with dimethylformamide in carbon disulfide (in the presence of magnesium sulphate) and analyzed by GC/FID. The advantages of this method are a high sampling capacity and improved storage stability for acetone. The expense of the sampling tubes is a disadvantage of this procedure. The detection limit of the overall procedure is 2.0 ppmv or 4.7 mg/m3 for a 3 L air sample. This is the amount of acetone spiked on the sampling device that allows recovery of an amount equivalent to the detection limit of the analytical procedure. The reliable quantitation limit is 2.0 ppmv or 4.7 mg/m3 . This is the smallest amount of acetone that can be quantified within the requirements of a recovery of at least 75% and a precision of ± 25% or better.

Reference:

Alberta Environment  ASSESSMENT REPORT ON ACETONE FOR DEVELOPING AMBIENT AIR QUALITY OBJECTIVES.-London:Toxico-Logic Consulting Inc. , 2004.-P.25-31.