Determination of 2,5-Hexanedione in Urine Using Headspace Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry

Ferenc Garay

Chemical Laboratory, Hungarian Institute of Occupational Health, Budapest, Hungary

Corresponding author: Ferenc Garay
    Hungarian Institute of Occupational Health
    Chemical Laboratory
    Nagyvárad tér 2
    H-1096 Budapest, Hungary
    E-mail: garayf@omfi.hu

CEJOEM 2007, Vol.13. No.2.: 115–140

Key words:
2,5-Hexanedione, n-hexane metabolite, urine, occupational exposure, biological monitoring, solid-phase microextraction (SPME), headspace, gas chromatography-mass spectrometry (GC-MS)

Abbreviations:

2,5-HD
GC
MS
GC-MS
HPLC
SPME
HS-SPME
DI-SPME

= 2,5-hexandione
= gas chromatography
= mass spectrometry
= gas chromatography-mass spectrometry
= high performance liquid chromatography
= solid-phase microextraction
= headspace solid-phase microextraction
= direct immersion solid-phase microextraction

PDMS
PTFE
SIM
S/N
ACGIH
.
FIOH
.

= polydimethylsiloxane
= polytetrafluoroethylene
= selected ion monitoring
= signal-to-noise ratio
= American Conference of
Governmental Industrial Hygienists
= Finnish Institute of Occupational Health
.

Abstract:
2,5-Hexandione (2,5-HD) is a neurotoxic metabolite of n-hexane (and methyl butyl ketone) excreted with urine. Because of the good correlation between exposure to n-hexane and urinary excretion of 2,5-HD, this substance can be used for biological monitoring of occupational exposure. In this paper, the combination of headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) for the determination of 2,5-HD in urine without using organic solvents is described. After acid hydrolysis (4% HCl, 98 °C, 2 hours), the urine sample was neutralized with sodium citrate. Sodium sulfate was added and the sample was stirred for 2 hours in a sealed glass vial at temperature of 28.0 °C. For HS-SPME sampling, polyacrylate coated fibre (85 µm) and extraction time of 10 min were applied. Analytes were desorbed at temperature of 260 °C for 1 min. Limit of detection (S/N of 3 : 1) was 0.01 mg L^–1. The inter-day reproducibility of the determination at concentration level of 5 mg L^–1 was 2.8%. Linearity was evaluated in the range of 1–25 mg L^–1. Using standard addition method with internal standard of methyl levulinate, the relative standard uncertainty of the determination at 5 mg L^–1 level was 3%.

Received: 4 October 2007
Accepted: 8 October 2007

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