ACETONE and METHYL ETHYL KETONE in urine: METHOD 8319, Issue 1, dated 28 October 2014 - Page 4 of 6
a. Suggested conditions for a balanced-pressure type of headspace system:
Transfer Temp: 129 °C Withdrawal: 0.2 min
Thermostat Time: 30 min Needle Temp: 120 °C
GC Cycle Time: 28 min Sample Temp: 80 °C Pressurize: 1.0 min Inject: 0.08 min
b. Suggested conditions for a syringe-injection type of headspace system: Incubation Temp: 95 °C Injection volume: 500 µL Incubation Time: 15 min Fill speed: 120 µL/sec Agitation speed: 250 rpm Delay: 5 sec Run time: 26 min Injection speed: 300 µL/sec Syringe Temp: 95 °C Delay: 500 msec
14. Measure peak area. Normalize the analyte response by dividing the peak area of the analyte by the peak area of the internal standard on the same chromatogram for each working standard, sample, and pooled urine blank. CALCULATIONS: 15. Determine both the acetone and MEK concentrations (mg/L) in the urine sample from the calibration graph prepared in Step 9f. EVALUATION OF METHOD: This method was evaluated over the ranges of the two analytes specified on p. 8319-1. These ranges represent from 1 x LOQ to 300 x LOQ. Six to seven replicates were analyzed at each level. The average recoveries at the various levels ranged from 94% to 106% for acetone and 85% to 98% for MEK. The LOD and LOQ were determined by preparing and analyzing a series of standards in duplicate with the data fitted to a quadratic curve. The LOD and LOQ were estimated according to Burkart’s Method [16]. A long-term storage study was carried out at the 10 x LOQ level. Pooled urine samples spiked with the analytes were stored at 4 °C for 1, 4, 7, 10, 21, or 30 days and then analyzed. All recoveries were nearly 100%. When stored at room temperature, a significant reduction in analyte recovery was observed after 7 days [5]. REFERENCES: [1] ACGIH [2013]. TLVs® and BEIs® based on the documentation of the Threshold Limit Values for chemical substances and physical agents and Biological Exposure Indices. Cincinnati, Ohio: American Conference of Governmental Industrial Hygienists. www.acgih.org [Date accessed: August 2014.] [2] Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area [2013]. List of MAK and BAT values 2013; Maximum concentrations and biological tolerance values at the workplace. DFG: Deutsche Forschungsgemeinschaft, Wiley-VCH Verlag GmbH & Co. www.dfg. de/en/dfg_profile/publications/senate_commissions/index.html#micro7535782 [Date accessed: August 2014.] [3] SUVA (Swiss National Accident Insurance Fund) [2013]. Protection de la santé au poste de travail. Valeurs limites d’exposition aux postes de travail. www.suva.ch/english/startseite-en-suva/ praevention-en-suva/publications-en-suva.htm [Date accessed: August 2014.] [4] Institut für Arbeitsschutz der Deutschen Gesetzlichen Unfallversicherung (IFA). www.dguv.de/ ifa/Gefahrstoffdatenbanken/GESTIS-Internationale-Grenzwerte-für-chemische-Substanzen-limitvalues-for-chemical-agents/index-2.jsp [Date accessed: August 2014.]
NIOSH Manual of Analytical Methods (NMAM), Fifth Edition
