Page:NIOSH Manual of Analytical Methods - 2559.pdf/3

 DEC ABR OM OD IPHEN YL OX IDE: ME TH OD 2559, Issue 1, dated 1 5 Ma rch 2003 - Page 3 of 4

CALIBRATION AND QUALITY CONTRO L: 6. Ca librate daily with at least six ca libration standards to cover the concentration range of the samples. A typical liquid chromatogram of a DBDPO standard is shown in Figure 1. a. Prepare calibration standards by adding kno wn am ounts of the DB DPO standard solution or a secon dary stock solution prepared from the standard solution to an au tosa m pler vial conta ining 1.5 mL DMSO. b. Analyze with samp les and blanks (steps 9 & 10 ). c. Prepare a calibration graph (pe ak area vs. µg DB DPO ). 7. Determine the recovery (R) of the an alyte fro m the sa m plin g m edia using the quartz fiber filters with analyte spikes in the concentration range of the samples (see step 6). Prepare three filters at each of five levels plus two media blanks. a. Place a filter spacer ring in the bottom section of a two part 37-m m filter cassette. Place a 37-m m quartz fiber filter on top of the spacer ring (do not use a s upport pad). b. Inoc ulate the filter with a known amount of calibration stock solution with a microliter syringe, place the top section of the cassette in place and seal the filter in place by squeezing the two sections together. c. Place the plugs in the inlet and outlet tubing stubs and set the cassettes aside for a minimum of twelve hours. d. Prepare the filter samples (steps 4 & 5) and analyze with the calibration standards. e. Prepare a graph of R vs. µg DBDPO. 8. Analyze three quality control blind spikes and three analyst spikes to ensure that the calibration graph and R gra ph are in control.

MEASUREMENT: 9. Se t the liquid chromatograph according to manufacturer’s recomm endations and to conditions given on page 2559-1. Inject sample with autosampler or by manual injection. NOTE: If peak area is above the linear range of the calibration standards, dilute the sample with DMSO, reanalyze, and app ly the app ropriate dilution facto r in calculation s. O r, prepare a calibration curve with stan dard s of h igher levels of D BD PO. 10. Measure peak area of DBDPO peak and determine µg per sample from calibration graph.

CALCULATIONS: 11. From the calibration graph, determ ine the ma ss, µg (correc ted for R) for the sam ple (W ), and average m edia blank (B). 12. Calculate conce ntration, C, of decabrom odiphenyl oxide in the air volume sam pled, V(L):

NO TE : :g/L = m g/m 3

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition