“…2). Aldehyde carbonyls reacted with DNPH amino groups forming the corresponding DNPH derivatives 25,26 . The yellow DNPH derivatives that were formed were concentrated and kept in MeOH prior to MS.Figure 2Synthesis routes of DNPH derivatives.…”
We developed a significantly improved ultra-high performance liquid chromatography-tandem mass spectrometry method for determination of 5-nitro-2-furaldehyde (NF) as a surrogate using a novel internal standard for the detection of nitrofurazone. We used 2,4-dinitrophenylhydrazine derivatization and furfural as the internal standard. Derivatization was easily performed in HCl using ultrasonic manipulation for 5 min followed by liquid extraction using ethyl acetate. The samples were concentrated and purified using reverse phase and alumina cartridges in tandem. The derivatives were separated using a linear gradient elution on a C18 column with methanol and water as the mobile phase in negative ionization mode and multiple reaction monitoring. Under the optimized conditions, the calibration curves were linear from 0.2 to 20 μg/L with correlation coefficients >0.999. Mean recoveries were 80.8 to 104.4% with the intra- and inter-day relative standard deviations <15% at spiking levels of 0.1 to 10 μg/kg. The limits of detection and quantification were 0.05 and 0.1 μg/kg, respectively. This method is a robust tool for the identification and quantitative determination of NF in shrimp samples.
“…2). Aldehyde carbonyls reacted with DNPH amino groups forming the corresponding DNPH derivatives 25,26 . The yellow DNPH derivatives that were formed were concentrated and kept in MeOH prior to MS.Figure 2Synthesis routes of DNPH derivatives.…”
We developed a significantly improved ultra-high performance liquid chromatography-tandem mass spectrometry method for determination of 5-nitro-2-furaldehyde (NF) as a surrogate using a novel internal standard for the detection of nitrofurazone. We used 2,4-dinitrophenylhydrazine derivatization and furfural as the internal standard. Derivatization was easily performed in HCl using ultrasonic manipulation for 5 min followed by liquid extraction using ethyl acetate. The samples were concentrated and purified using reverse phase and alumina cartridges in tandem. The derivatives were separated using a linear gradient elution on a C18 column with methanol and water as the mobile phase in negative ionization mode and multiple reaction monitoring. Under the optimized conditions, the calibration curves were linear from 0.2 to 20 μg/L with correlation coefficients >0.999. Mean recoveries were 80.8 to 104.4% with the intra- and inter-day relative standard deviations <15% at spiking levels of 0.1 to 10 μg/kg. The limits of detection and quantification were 0.05 and 0.1 μg/kg, respectively. This method is a robust tool for the identification and quantitative determination of NF in shrimp samples.
“…Both eld observations and laboratory experiments demonstrate CE changes for carbonyls depending on RH, sample ow rates, sample durations, and concentration levels. 36 Commercially available carbonyl samplers with inlets heated to 50 C can remove water droplets (i.e., rainfall) from the air stream, but an elevated RH affects CEs. Table 3 summarizes the interference and solutions related to the DNPH-coated cartridge method.…”
This paper examines the collection efficiencies of acetone and methyl ethyl ketone under different relative humidities, flow rates, and sample durations, for ambient sampling and laboratory experiments.
“…Potential drawbacks existed in the method for sampling air carbonyls using DNPH-coated silica cartridges, mainly including: (1) ambient O 3 was the critical interference using DNPH-coated solid sorbent cartridges; (2) environmental relative humidity could inhibit derivatization kinetics and contributed to degradation of carbonyl-DNPH derivatives during sampling (Saha et al, 2012;Ho et al, 2013); (3) sampling volume and concentration also influenced the analysis of carbonyls using DNPH cartridges (Pal and Kim, 2008a); (4) unsaturated carbonyls such as acrolein were not accurately quantified using the DNPH method (Ho et al, 2011); and (5) the HPLC method was reliable for low-weight carbonyls, while gas chromatography was more suitable for high-weight carbonyls (Pal and Kim, 2008b;Kim and Pal, 2010;Pang et al, 2011;Xie et al, 2013). However, these potential drawbacks could be minimized though the experiments of quality assurance in the method (Feng et al, 2005;Lü et al, 2010).…”
Ambient carbonyls in urban air in Qinzhou were studied form October 2011 to July 2012 to investigate their distribution characteristics and sources. Acetaldehyde (8.04 ± 9.00 µg/m 3 ), formaldehyde (6.70 ± 6.36 µg/m 3 ) and acetone (2.43 ± 2.81 µg/m 3 ) were three most abundant carbonyls, accounting for ~90% of the seven carbonyls identified. Concentrations of most carbonyls showed significantly higher levels in spring and summer than those in autumn and winter. Seasonal and diurnal variations indicated that formaldehyde and acetaldehyde were related to barbecue emissions and photochemical loss, while solvent usage was responsible for acetone. The average C 1 /C 2 ratio was higher (1.92) in summer than that during other seasons (0.52-1.78), implying the positive impact of photochemical loss or formation; and a significantly lower C 2 /C 3 ratio (2.57) was observed in winter than during other seasons (12.47-52.82), suggesting significant emissions from straw burning and barbecues. Formaldehyde and acetaldehyde were the two major contributors (63-97%) to O 3 formation, particularly in spring and summer.
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