Simultaneous determination of cyanide and thiocyanate in milk by GC-MS/MS using cetyltrimethylammonium bromide as both phase transfer catalyst and protein precipitant.

A method was developed for simultaneous determination of cyanide and thiocyanate in milk by gas chromatography-tandem quadrupole mass spectrometry (GC-MS/MS). Cyanide and thiocyanate were derivatized with pentafluorobenzyl bromide (PFBBr) as PFB-CN and PFB-SCN, respectively. Cetyltrimethylammonium bromide (CTAB) was employed both as a phase transfer catalyst and a protein precipitant in the sample pretreatment, which facilitates the separation of the organic and aqueous phases, and greatly simplifies the pretreatment procedures to achieve simultaneous and rapid determination of cyanide and thiocyanate. Under the optimized conditions, the limits of detection (LODs) of cyanide and thiocyanate in milk were 0.006 mg/kg and 0.015 mg/kg, and the spiked recoveries ranged from 90.1% to 98.2% and from 91.8% to 98.9% with relative standard deviations (RSDs) less than 18.9% and 15.2%, respectively. The proposed method was validated as a simple, fast and highly sensitive method for the determination of cyanide and thiocyanate in milk.

Comprehensive investigation of the content and the origin of matrine-type alkaloids in Chinese honeys.

A HPLC-MS/MS method for simultaneous determination of four matrine-type alkaloids (matrine, oxymatrine, sophocarpine and sophoridine) in honey was established and was applied to 567 Chinese honey samples. The overall detection rate was 61.0 % and all eight Sophora viciifolia Hance honey samples were detected with the average content of 1183.3 µg/kg. Among 383 Acacia honey samples, matrine-type alkaloids have the highest detection rates in Gansu (98.8 %) and Shaanxi (86.5 %) provinces, which were significantly correlated with the distribution of S. viciifolia Hance. Moreover, matrine-type alkaloids in fruits and flowers of S. viciifolia Hance were as high as 7.06 g/kg and 2.65 g/kg respectively. The melissopalynological analysis showed that the concentration of oxymatrine was positively correlated with the pollen frequency of S. viciifolia Hance (R2 = 0.737) in representative Acacia honey samples. It can be concluded that the matrine-type alkaloids in Chinese honeys come from the nectariferous plants S. viciifolia Hance.