Page:NIOSH Manual of Analytical Methods - 2551.pdf/3

 NICOTINE: METHOD 2551, Issue 1, dated 15 January 1998 - Page 3 of 4 9. Calibrate daily with at least six working standards over the range of interest. a. Add known amounts of the nicotine stock solution to 1.0 mL of desorbing solution in separate vials. b. Add amount of quinoline secondary stock solution equal to amount used in Step 7 to each vial. c. Seal vials with PTFE-lined crimp caps. d. Analyze together with samples and blanks (steps 12 through 14). e. Prepare calibration graph (ratio of nicotine/quinoline areas vs. µg nicotine). 10. Determine desorption efficiency (DE) at least once for each lot of XAD-4 tubes used for sampling in the calibration range (step 9). Prepare three samplers at each of six levels plus three media blanks. a. Remove and discard the back sorbent section of the sampler. b. Inject a known volume of calibration stock solution directly onto the front sorbent bed of each XAD-4 tube. c. Allow the tubes to air equilibrate for several minutes, then cap the ends of the tubes and allow to stand overnight. d. Desorb (steps 6 through 8) and analyze together with standards and blanks (steps 12 through 14). e. Prepare a graph of DE vs. µg nicotine recovered. 11. Analyze three quality control blind spikesand three analyst spikes to ensure that the calibration graph and DE graphs are in control.

MEASUREMENT: 12. Set gas chromatograph according to manufacturer’s recommendations and to conditions given on page 2551-1. 13. Inject a 1-µL sample aliquot manually using solvent flush technique or with an autosampler. NOTE: If peak area is abovethe linear range of the working standards, dilute with desorbing solution, reanalyze, and apply the appropriate dilution factor in the calculations. 14. Measure peak areas and calculate ratio of nicotine peak area to quinoline peak area.

CALCULATIONS: 15. Determine the mass, µg (corrected for DE), for nicotinefound in the sample front (Wf) and back (Wb) sorbent sections, and in the average media blank front (B f) and back (Bb)sorbent sections. NOTE: If Wb > Wf/10, report breakthrough and possible sample loss. 15. Calculate concentration, C, of nicotine in the air volume sampled, V (L):

C

NOTE: µg/L

Wf

Wb

Bf V

Bb

, mg/m 3

mg/m3

EVALUATION OF METHOD: This method development was based upon a request to measure nicotine in environmental tobacco smoke and an HHE request to measure nicotine in a greenhouse pesticide application. Desorption efficiency (DE) was determined for 5 levels: 2 x LOQ; 0.1, 0.5, 1.0, and 2.0 x Recommended Exposure Limit (REL) using the analytical parameters stated on page 2551-1. The average DE for nicotine was determined to be 0.924. The instrumental LODwas determined at 0.013 µg/sample. The precision, as determined from the pooled relative standard deviation ( r) was 0.024. Nicotine storage stability at 5 C and at a concentrationof 0.5 x REL was acceptable after 14 days with a mean recovery of 91%. This method was employedto analyze nicotine that was used as a greenhouse pesticide and applied by a fogging procedure. In addition to XAD-4 sorbent tubes, nicotine was collected on glass fiber filters, gauze wipes, and cotton gloves. Nicotine was not stable on these media for more than 1 h. Recovery data for nicotine spiked on these media is contained in the method backup data report [4].

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition