Ethyl Glucuronide

Ethyl glucuronide (EtG) is a minor metabolite of ethanol and is formed from ethanol by conjugation with uridine diphosphate (UDP)-glucuronic acid. EtG has been detected in human urine, serum and clipped hair samples of ethanol consumers. The formation of EtG depends on the serum ethanol concentration. It was shown that serum EtG concentrations higher than 5mgL~1 may indicate alcohol misuse, especially if the serum ethanol concentration is less than 1 gL"1. The EtG concentration declines exponentially with a half-life of 2-3 h and testing for EtG is restricted to a period of about 6-18 h after drinking, depending on the ethanol dose and individual metabolism. In forensic cases testing is predominantly indicated when the ethanol determination gives nega tive results and consumption is denied. For retrospective studies detection of EtG in hair samples also seems to be possible. However, if excessive ethanol consumption over a period of months or years provokes a stimulation of glucuronyltransferase in the liver, the extent of the EtG formation might be an indicator of ethanol abuse.

For the determination of EtG in serum the sample is precipitated with acetone or methanol and the dried supernatant is derivatized by addition of acetic anhydride and pyridine. A mass spectrum of the triacetyl derivative is shown in Figure 4. Hair samples are extracted with methanol, including treatment by ultrasound prior to derivatization. On an OV-1 capillary column, the retention index is 1920. Gas chromatography-mass spectrometry (GC-MS) was performed with an electron energy of 70 eV and gave the following m/z values (intensities higher than 20% in parentheses): 85 (53), 88 (41), 101 (38), 113 (66), 114 (42), 115 (100), 117 (47), 130 (25), 157 (73), 142 (25) and 143 (28); there is no parent peak. An m/z value of 303 (1%, M-45) indicates that EtG is decarboxylated.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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