Development of a method for the determination of naphthalene and phenanthrene in workplace air using diffusive sampling and thermal desorption GC-MS analysis.

Diffusive sampling methods have been validated for the determination of naphthalene and phenanthrene in workplace air. The diffusive sampler tested was the Perkin Elmer ATD tube, and the analysis was performed with thermal desorption, gas chromatography, and mass spectrometric detection. The sampling methods were validated in controlled test atmospheres, mainly according to the protocol proposed in the European standard EN 838. For the determination of naphthalene, the diffusive sampling rate was 0.41 ml min(-1) with a coefficient of variation (CV) of 19%. The mean sampling rate for phenanthrene was 0.49 ml min(-1) with a CV of 21%. Field tests confirmed the naphthalene results but could not be used to confirm the phenanthrene results. The method is not recommended for phenanthrene sampling unless the method has been tested in the specific environment and the results confirm the laboratory tests.

Field evaluation of a passive personal air sampler for screening of PAH exposure in workplaces.

New sampling methods are needed to simplify and enable frequent monitoring of workers' exposure to polycyclic aromatic hydrocarbons (PAHs). The sampler needs to fulfil some key operational requirements for occupational exposure assessments: (i) be usable as a personal sampler; (ii) work over 8 h exposure time; (iii) sequester PAHs both in gas and particle phase, (iv) yield reliable estimates of air concentrations. Here, a new smaller design of the traditional polyurethane foam (PUF) passive air sampler (PAS) (i.e. a 'mini-PUF') was introduced and assessed against these requirements in sites with elevated PAH concentrations. The exposure times were 2 weeks and 8 hours. The obtained sampling rates (R-values) were not significantly different between gas phase (0.4-3.3 m(3) day(-1), 0.3-2.3 L min(-1)) and particle associated PAHs (0.5-1.9 m(3) day(-1), 0.4-1.3 L min(-1)). The accuracy in estimating air concentrations was within +/-25% from the active sampler for half of the PAHs for the mini-PUF under 8 h exposures. Significant correlations (p < 0.003) were found between personally deployed mini-PUFs and a co-deployed personal active sampling method. This together with the low costs and ease-of-use of the mini-PUF encourage application in exposure assessments.

Development of a miniaturized diffusive sampler for true breathing-zone sampling and thermal desorption gas chromatographic analysis.

Exposure measurements should be performed as close as possible to the nose and mouth for a more correct assessment of exposure. User-friendly sampling equipment, with a minimum of handling before, during and after measurement, should not affect ordinary work. In diffusive (passive) sampling, no extra equipment as sampling pumps is needed, making the measurements more acceptable to the user. The diffusive samplers are normally attached on a shoulder, on a breast-pocket or on the lapel. There are, however, difficulties if true breathing-zone sampling is to be performed, since available diffusive samplers normally cannot be arranged close to the nose/mouth. The purpose of this work was to study the performance of a miniaturized tube type diffusive sampler attached to a headset for true breathing-zone sampling. The basis for this miniaturization was the Perkin Elmer ATD tube. Both the size of the tube and the amount of adsorbent was decreased for the miniaturized sampler. A special tube holder to be used with a headset was designed for the mini tube. The mini tube is thermally desorbed inside a standard PE tube. The new sampler was evaluated for the determination of styrene, both in laboratory experiments and in field measurements. As reference method, diffusive sampling with standard Perkin Elmer tubes, thermal desorption and gas chromatographic (GC) analysis was used. The sampling rate was determined to 0.356 mL min(-1) (CV 9.6%) and was not significantly affected by concentration, sampling time or relative humidity.

Formaldehyde levels in Sweden: personal exposure, indoor, and outdoor concentrations.

Formaldehyde is a ubiquitous environmental pollutant and is probably carcinogenic to humans. Exposure to formaldehyde was investigated in the general population with personal as well as stationary measurements. The results from two campaigns in two Swedish cities are presented, including measurements of personal exposure among a total of 65 randomly selected subjects together with simultaneous measurements of individual indoor and outdoor concentrations. Diffusive GMD samplers were placed in the breathing zone, in the participants' bedrooms, and outside their homes for 24 h in campaign A and six days in campaign B. Repeated measurements were also conducted in order to study the variability between and within individuals. Median personal exposure to formaldehyde was 22 microg/m(3) (campaign A) and 23 microg/m(3) (campaign B), which is within the guideline value range of 12-60 microg/m(3) proposed in Sweden. Bedroom concentrations were generally slightly higher than personal exposure, while outdoor concentrations (measured only in campaign B) were low. In campaign B, the stationary measurements were used to model personal exposure. Bedroom concentrations were found to explain 90% of the variation of the measured personal exposure and predicted personal exposure nearly as well as an extended model that also included the outdoor contribution. Subjects living in single-family houses had significantly higher exposure to formaldehyde compared with subjects living in apartments. The 24-h and 6-day sampling periods yield a relatively low within-individual variability for formaldehyde measurements with GMD samplers.

Diffusive sampling of methyl isocyanate using 4-nitro-7-piperazinobenzo-2-oxa-1,3-diazole (NBDPZ) as derivatizing agent.

A diffusive sampling method for the determination of methyl isocyanate (MIC) in air is introduced. MIC is collected using a glass fiber filter impregnated with 4-nitro-7-piperazinobenzo-2-oxa-1,3-diazole (NBDPZ). The urea derivative formed is desorbed from the filter with acetonitrile and analyzed by means of high-performance liquid chromatography (HPLC) using fluorescence detection (FLD) with lambdaex = 471 nm and lambdaex = 540 nm. Additionally, a method was developed using tandem mass spectrometric (MS-MS) detection, which was performed as selected reaction monitoring (SRM) on the transition [MIC-NBDPZ + H]+ (m/z 307) to [NBDPZ + H]+ (m/z 250). The diffusive sampler was tested with MIC concentrations between 1 and 35 microg m(-3). The sampling periods varied from 15 min to 8 h, and the relative humidity (RH) was set from 20% up to 80%. The sampling rate for all 15 min experiments was determined to be 15.0 mL min(-1) (using HPLC-FLD) with a relative standard deviation of 9.9% for 56 experiments. At 80% RH, only 15 min sampling gave acceptable results. Further experiments revealed that humidity did not affect the MIC derivative but the reagent on the filter prior to and during sampling. The sampling rate for all experiments (including long term sampling) performed at 20% RH was found to be 15.0 mL min(-1) with a relative standard deviation of 6.3% (N = 42). The limit of quantification was 3 microg m(-3) (LC-MS-MS: 1.3 microg m(-3)) for 15 min sampling periods and 0.2 microg m(-3) (LC-MS-MS: 0.15 microg m(-3)) for 8 h sampling runs applying fluorescence detection.

Development of a diffusive sampling method for determination of methyl isocyanate in air.

A diffusive sampling method for determination of methyl isocyanate in air has been developed. A glass fibre filter impregnated with 1-(2-methoxyphenyl)piperazine in a commercially available diffusive sampling device was used to collect methyl isocyanate and the derivative formed was analysed with LC-MS/MS. The sampling rate was determined to be 15.6 ml min(-1), with a relative standard deviation of 7.3%. The sampler was validated for sampling periods from 15 min to 8 h, for relative humidities from 20% to 80% and for concentrations from I to 46 microg m(-3). A field validation was also made and the diffusive sampling results showed no difference compared to a pumped reference method. The impregnated filters have to be stored apart from the diffusive sampler housing and loaded into the sampler prior to each sampling.

Validation of the Willems badge diffusive sampler for nitrogen dioxide determinations in occupational environments.

The Willems badge, a diffusive sampler for nitrogen dioxide, has previously been validated for ambient air measurements. This paper describes the laboratory and field validation of the Willems badge for personal sampling under working environment conditions. The mean sampling rate in the laboratory tests was 46 ml min(-1), with an RSD of 12%. No statistically significant effects on sampling rate of the sampling time, concentration of NO2 or relative humidity were found. A slightly decreased sampling rate was observed at low wind velocity. This was also confirmed during static sampling, which makes the sampler less appropriate for static sampling indoors. No back diffusion was observed. Storage of the samplers for two weeks before or after exposure did not affect the sampling rate. Our analysis is based on a modified colorimetric method, performed by FIA (flow injection analysis). This technique was compared to ion chromatography analysis. The use of ion chromatography lowered the detection limit from 11 to 2 microg m(-3) for an 8 h sample, and furthermore enabled the detection of other anions. In conclusion, the diffusive sampler was found to perform well for personal measurements in industrial environments.

Comparison of sampling methods for 1,6-hexamethylene diisocyanate, (HDI) in a commercial spray box.

In this study three different types of samplers for the determination of 1,6-hexamethylene diisocyanate in air were compared. The experimental set up was a simulation of real life conditions with spray painting operations performed inside a commercial, full sized, spray box. The sampling methods were 1-(2-methoxyphenyl)-piperazine impregnated on glass fibre filter, and the same reagent in impinger, and also dibutylamine in impinger. All analyses were performed by LC-MS-MS. The determined concentrations varied between 20 and 90 microg m(-3) with relative standard deviations from 7 to 17% for each method. No significant difference was found between the three methods using ANOVA with a significance level of alpha = 0.05.