Determination of cefuroxime lysine in rat brain microdialysates by ultra-fast liquid chromatography with UV and tandem mass spectrometry: application to an acute toxicokinetic study.

Cefuroxime lysine is a new second-generation cephalosporins, which can penetrate the blood-brain barrier to cure the meningitis. In order to investigate its acute toxicokinetic study after intraperitoneal injection of 675 mg/kg cefuroxime lysine, a sensitive and clean ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method for the determination of cefuroxime lysine in microdialysate samples was developed and validated, which was compared with UFLC-UV as a reference method. Chromatographic separation was performed on a Shim-pack XR-ODS C18 column (75 × 3.0 mm, 2.2 µm), with an isocratic elution of 0.1% formic acid in acetonitrile-0.1% formic acid in water (45:55, v/v) for LC-MS and acetonitrile-20 mm potassium dihydrogen phosphate (pH 3.0,20:80, v/v) for LC-UV. The lower limit of detection was 0.01 µg/mL for LC-MS and 0.1 µg/mL for LC-UV method, with the same corresponding linearity range of 0.1-50 µg/mL. The intra- and inter-day precisions (relative standard deviation) for both methods were from 1.1 to 8.9%, while the accuracy was all within ±10.9%. The results of both methods were finally compared using paired t-test; the results indicated that the concentrations measured by the two methods correlated significantly (p < 0.05), which suggested that the two methods based on LC-MS and LC-UV were suitable for the acute toxicokinetic study.

Fast, easy, cheap, robust and safe method of analysis of Sudan dyes in chilli pepper powder.

Illicit use of Sudan dyes, a group of harmful and carcinogenic azo dyes, in the food industry has taken a surge in various parts of the world, especially in Africa. Their use in food as additives pose a dire health risk to consumers and have been banned by various food regulatory bodies worldwide. To help increase surveillance, various methods have been proposed for their analysis in literature. This study also sought to experiment and propose an alternative method for quick, easy, cheap, robust and ecologically safe analysis of Sudan dyes in chilli pepper powder and similar matrices. The optimized method used a 6.0 mL mixture of acetone:acetonitrile (1:5 v/v) solvent in a modified QuEChERs method for extraction of Sudan dyes I-IV. The simultaneous analysis of the dyes were achieved on Shimadzu prominence UFLC 20AD coupled with SPD 20AX UV detector operated at dual wavelength of 500 and 480 nm. A total of twenty four (24) chilli pepper powder samples from eight different vendors on the Ghana market were analysed using the optimized method. Quantitation of analytes were done using the external standard calibration method with determination coefficient, R2 > 0.9999. The limit of detection (LOD) and limit of quantitation (LOQ) of the method were 0.02-0.04 mg/kg and 0.05-0.13 mg/kg respectively. A good recovery range between 85.3 - 121.2% were obtained for a spike level of 1.0 mg/kg in real samples. ANOVA analysis at 95% CL showed statistically no significant difference (p > 0.05) in the recoveries between samples and also between the individual compounds. The method experimented and proposed in this study is fast, easy, cheap, robust and ecologically safe, presenting an alternative method for routine analysis for increased rate of surveillance against the illicit use of Sudan dyes as food additives.