Determination Of Airborne Carbonyl Compounds Using Pentafluorophenyl Hydrazine As A Derivating Agent With Gas Chromatography/Mass Spectrometry

Carbonyls (aldehydes and ketones) are an important class of volatile organic compounds in atmospheric chemistry of the troposphere and continue to receive scientific and regulatory attention as their important role in photochemistry and for the toxic air contaminants which can cause suspected carcinogens, eye irritants, and mutagens to human. However, as the concentrations of carbonyl in the atmospheric environment is relatively low, and most carbonyl compounds have strong polarity, high volatility and reactivity, they are easy to react or decompose in the process of sampling and analysis, therefore the analytical method for determination of gaseous carbonyls has been a challenging problem all the time.In this paper, a new, sensitive and reliable method was developed for the simultaneous determination of twenty airborne carbonyl compounds in the C1-C10 range (PFPH/GC/MS method). The carbonyls were collected onto solid sorbent coated with pentafluorophenyl hydrazine (PFPH), followed by solvent extraction and gas chromatographic (GC)/mass spectrometric (MS) analysis of the PFPH derivatives. The sorbent is packed into two separate sections in a glass sampling tube. The two-section design allows convenient checking of collection efficiency and breakthrough. Compare with traditional DNPH/LC-UV method and DNPH-LC-ESI/MS/MS method, the PFPH method has much lower LODs and the LODs of the tested carbonyls are in the range of 0.15-1.04ng/m3 (as a assumption sampling volume of 9.6L). The determination coefficients of the calibration curves (R2), relative standard deviations (RSD) of duplicates (n=6) , recoveries(TenaxTA was new) and extraction efficiency of the 20 carbonyl compounds were in the range of 00.995~1.0,7.3%~15.8%,92.7%~109.2% and 95.8%~99.62%, respectively. With a coating amount of 971 nmol PFPH per 100 mg Tenax TA and operated at a sampling flow rate of 80 mL/min, the sampling tube's collection efficiencies for twenty carbonyls were all above 95%. Concentrations of formaldehyde and benzaldehyde reached stable values after two days of storage while three days for decylaldehyde. No pronounced losses in the yields of the carbonyls PFPH hydrazone were found when the storage time≦5 days. It is necessary to let the sampling tube sit at ambient temperature for 3 days before solvent extraction to ensure complete derivatization of the carbonyls.Lastly, Compare field test with traditional DNPH/LC-UV method, good agreement exited between the two methods for lower molecular carbonyls(