A direct comparison of liquid chromatography-mass spectrometry with clinical routine testing immunoassay methods for the detection and quantification of thyroid hormones in blood serum.

A new and improved method was developed for the determination and quantification of four "free" thyroid hormones (i.e. 3,5-diiodothyronine (T2), 3,3',5-triiodothyronine (T3), 3,3',5'-triiodothyrone (rT3) and 3,5,3',5'-tetraiodothyronine (T4)) in human serum by low- and high-resolution liquid chromatography-mass spectrometry (LC-MS). Several sample preparation strategies were investigated to obtain matrix-independent results. These strategies included solid phase extraction and matrix dilution. The developed analytical methods were then directly compared, in a blind study using patient-derived human blood serum samples, to the current clinical routine testing methods, i.e. electrochemiluminescence immunoassay and enzyme-linked immunosorbent assay. Chromatographic separation was achieved on a pentafluorophenyl (F5) column with an isocratic method of 30% aqueous phase, 70% organic phase where mobile phase A is 0.1% formic acid in water (pH 4) and mobile phase B is 0.1% formic acid in methanol (pH 4) (v/v). The high-resolution LC-MS was able to give a significant improvement in sensitivity with limits of quantification of 0.002 to 0.008 pmol/L for all four "free" thyroid hormones, as well as reduced sample preparation, making this the preferred method. However, the increase in capital cost may be beyond the capabilities of some laboratories. The LC-MS methods allow for the analysis of "free" thyroid hormones to be carried out in a significantly reduced analysis time. Clinical sample analysis showed that there was no statistical difference between the results obtained by ECLIA/ELISA and both LC-MS methods. Graphical abstract.

Opium Alkaloids in Harvested and Thermally Processed Poppy Seeds.

The opium alkaloids (morphine, codeine, thebaine, noscapine, and papaverine) have been detected on poppy seeds; they are widely used by the food industry for decoration and flavor but can introduce opium alkaloids into the food chain. Of the opium alkaloids found on poppy seeds, morphine, and codeine are the most pharmacologically active and have been detected in biological matrices collected in workplace and roadside drug testing resulting in positive opiate results. The European Food Safety Authority introduced an acute reference dose of 10 µg morphine/kg of body weight as a safe level for morphine in food products. In this work, it was found that in harvested poppy seeds, and thermally processed poppy seeds (with and without a food matrix), if used in normal levels would not exceed the recommended acute reference dose. It was also shown that the levels of all alkaloids reduce when thermally processed, in comparison with harvested, untreated seeds.

Investigation of the acid/base behaviour of the opium alkaloid thebaine in LC-ESI-MS mobile phase by NMR spectroscopy.

As part of a research programme to establish an analytical method for the simultaneous detection of the five major opium alkaloids in poppy seeds by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) it was discovered that the inclusion of thebaine produced two peaks for the same compound. This was in contrast to the effective simultaneous detection, by LC-ESI-MS, of morphine, codeine, papaverine and noscapine. The presence of these two peaks for thebaine was investigated using nuclear magnetic resonance spectroscopy with deuterated solvents to emulate the mobile phase conditions experienced. It was found that the presence of 80%, or higher ratios of, water caused two epimeric forms of thebaine to be formed; this explained the presence of two peaks on the chromatogram. In contrast, when a lower water content was used with 1% acetic acid, one stable form of thebaine could be analysed and resulted in a single peak visible in the subsequent chromatography.

Post-mortem toxicology: A pilot study to evaluate the use of a Bayesian network to assess the likelihood of fatality.

The challenge of interpreting post-mortem drug concentrations is well documented and relies on appropriate sample collection, knowledge of case circumstances as well as reference to published tables of data, whilst taking into account the known issues of post-mortem drug redistribution and tolerance. Existing published data has evolved from simple data tables to those now including sample origin and single to poly drug use, but additional information tends to be specific to those reported in individual case studies. We have developed a Bayesian network framework to assign a likelihood of fatality based on the contribution of drug concentrations whilst taking into account the pathological findings. This expert system has been tested against casework within the coronial jurisdiction of Sunderland, UK. We demonstrate in this pilot study that the Bayesian network can be used to proffer a degree of confidence in how deaths may be reported in cases when drugs are implicated. It has also highlighted the potential for deaths to be reported according to the pathological states at post-mortem when drugs have a significant contribution that may have an impact on mortality statistics. The Bayesian network could be used as complementary approach to assist in the interpretation of post-mortem drug concentrations.