Determination of taurine in biological samples by reversed-phase liquid chromatography with precolumn derivatization with dinitrofluorobenzene

Taurine for EPR dosimetry

EPR dosimetry is characterized by its non-destructive read-out and the possibility of dose archival. Here, taurine is proposed as a radiation dosimeter using EPR spectroscopy. The EPR spectrum of taurine was studied and assigned, and changes in the taurine EPR spectrum as a result of the change in both modulation amplitude and microwave power were quantified. For gamma radiation, the energy absorption coefficient and the collision mass stopping power of taurine were compared to the corresponding values of soft tissue and alanine, in addition to calculation of effective atomic numbers. The response of taurine to gamma radiation doses in the range from 0.1 to 50 kGy was investigated, as well as that in the range from 1.0 to 20.0 Gy using numerically enhanced EPR taurine spectra. Both response curves showed a linear behavior. In addition, the time dependence of radiation-induced radicals was studied for short (during the first 6 h after irradiation) and long (during about 3 months after irradiation) time periods, and a reasonable degree of stability of the taurine radicals was observed. It is concluded that taurine is a promising dosimeter, which is characterized by its simple spectrum, radical stability, and wide range of linear response to gamma radiation.

Effects of dietary taurine on egg production, egg quality and cholesterol levels in Japanese quail

BACKGROUND

Taurine is a semi-essential amino acid and has many biological properties. The objective of this study was to determine the effect of dietary supplementation with taurine on egg production, egg quality, and cholesterol level in serum and egg yolk of quails. A total of 108 quails aged 6 weeks were randomly allocated to three dietary treatments. Each treatment consisted of four replicates of nine quails. The diets were supplemented with 0, 100, and 500 mg kg(-1) of taurine for 8 weeks.

RESULTS

Dietary 500 mg kg(-1) taurine significantly affected egg production rate and feed conversion ratio, but had no significant effects on body weight gain, feed consumption, or egg weight. Dietary taurine had no significant effect on egg quality parameters studied. Serum triglyceride concentration was reduced significantly with supplementation of taurine at 100 and 500 mg kg(-1). Egg yolk cholesterol content was reduced significantly, and the contents of serum taurine and egg yolk taurine were increased significantly with taurine supplementation at 500 mg kg(-1).

CONCLUSION

Results of the present study indicated that adding 500 mg kg(-1) taurine reduced yolk cholesterol concentration and increased yolk taurine content without adverse effects on performance and egg quality of laying quails.

33S nuclear magnetic resonance spectroscopy of biological samples obtained with a laboratory model 33S cryogenic probe

(33)S nuclear magnetic resonance (NMR) spectroscopy is limited by inherently low NMR sensitivity because of the quadrupolar moment and low gyromagnetic ratio of the (33)S nucleus. We have developed a 10 mm (33)S cryogenic NMR probe, which is operated at 9-26 K with a cold preamplifier and a cold rf switch operated at 60 K. The (33)S NMR sensitivity of the cryogenic probe is as large as 9.8 times that of a conventional 5 mm broadband NMR probe. The (33)S cryogenic probe was applied to biological samples such as human urine, bile, chondroitin sulfate, and scallop tissue. We demonstrated that the system can detect and determine sulfur compounds having SO(4)(2-) anions and -SO(3)(-) groups using the (33)S cryogenic probe, as the (33)S nuclei in these groups are in highly symmetric environments. The NMR signals for other common sulfur compounds such as cysteine are still undetectable by the (33)S cryogenic probe, as the (33)S nuclei in these compounds are in asymmetric environments. If we shorten the rf pulse width or decrease the rf coil diameter, we should be able to detect the NMR signals for these compounds.

33S NMR cryogenic probe for taurine detection

With the goal of a (33)S nuclear magnetic resonance (NMR) probe applicable to in vivo NMR on taurine-biological samples, we have developed the (33)S NMR cryogenic probe, which is applicable to taurine solutions. The NMR sensitivity gain relative to a conventional broadband probe is as large as 3.5. This work suggests that improvements in the preamplifier could allow NMR measurements on 100 microM taurine solutions, which is the level of sensitivity necessary for biological samples.

Quantitative on-chip determination of taurine in energy and sports drinks

A new method for the quantitative determination of taurine in beverages by microchip electrophoresis was developed. A rapid and simple sample preparation procedure, only including two dilution steps and the addition of the fluorogenic labeling reagent NBD-Cl (4-chloro-7-nitrobenzofurazan), is applied. Using a home-built wavelength-resolved fluorescence detector, the separation and determination of the taurine derivative could be achieved in only 12 s, while the additional spectral information was utilized to ensure peak purity. Spanning from 0.1 to 50 mmol L(-1), the linear dynamic range of the applied method was adapted to the apparent contents in common taurine containing beverages. The smallest detectable amount of the taurine derivative actually injected into the separation channel was as low as 60 amol. The method was successfully validated by an independent liquid chromatographic method.

Development and validation of a high-performance liquid chromatography–mass spectrometry assay for methylxanthines and taurine in dietary supplements

A procedure based on liquid chromatography-mass spectrometry (LC-MS) is described for determination of caffeine, theobromine, theophylline, taurine in different dietary supplements. After addition of tryptophan as internal standard, both solid and liquid specimens were extracted with 4 ml of hexane/isopropanol (9:1). Chromatography was performed on a C18 reversed-phase column using water/methanol/acetic acid (75:20:5, v/v/v) as a mobile phase. Analytes were determined in LC-MS single ion monitoring mode with atmospheric pressure ionization-electrospray (ESI) interface. The method was validated in the range 0.1-500 and 0.06-500 microg/ml or microg/g for taurine and caffeine, respectively; 0.06-100 microg/ml or microg/g for theobromine and theophylline. Mean recoveries ranged between 70.1 and 94.4% for different analytes. The quantification limits were 0.1 microg/ml or microg/g for taurine and 0.06 microg/ml or microg/g for methylxanthines either in liquid samples or in solid samples. The method was applied to the analysis of various dietary supplements containing methylxanthines and taurine. Energetic drinks contained amounts of taurine in the range of hundreds to thousands microg/ml and ten times lower amounts of caffeine. Conversely, herbal powders, tablets and capsules mainly contained mg amounts of caffeine per gram of product with the other two methylxanthines in the range of ten to hundred microg/g.

Separation methods for taurine analysis in biological samples

Taurine plays an important role in a variety of physiological functions, pharmacological actions and pathological conditions. Many methods for taurine analysis, therefore, have been reported to monitor its levels in biological samples. This review discusses the following techniques: sample preparation; separation and determination methods including high-performance liquid chromatography, gas chromatography, ion chromatography, capillary electrophoresis and hyphenation procedures. It covers articles published between 1990 and 2001.

Ion chromatographic determination of taurine in medicine, nutrient capsule and human urine with electrochemical detection

A very simple and sensitive method for the determination of taurine by ion chromatography with electrochemical integrated pulsed amperometry is firstly described. Taurine was determined using 160 mmol/l NaOH as eluent and a Dionex CarboPac PA1 separation column (250x4 mm I.D.) without the interference with ten kinds of common amino acids. The peak area response of taurine was linear in the range 0.1-20 microg/ml, the detection limit was 0.034 microg/ml. The method has been applied successfully in the determination of taurine in medicinal granule, nutrient capsule and human urine. The content determined in medicinal granule is consistent with that marked by the manufacturer.