A study was carried out to determine arsenic species in seafood samples collected from Chinese sea. The information about arsenic species in samples was provided by high performance liquid chromatography-inductively coupled plasma mass spectrometer (HPLC ICP MS) and electrospray tandem mass spectrometry (ES MS MS). The arsenic species in thirty Chinese edible seafoods, including algae, fish, crab, shrimp, mussels, oysters, and clams popularly ingested by Chinese people as regular foods, were examined in the present report. Arsenosugars were detected in all of the extracted algae samples (1 5—33 8μg·g -1 dry weight) and some shellfish samples (0 018—0 78μg·g -1 wet weight). Arsenobetaine was detected in all of the extracted fish and shellfish samples (0 025—6 604μg·g -1 wet weight). In contrast, inorganic arsenic was only present in the examined fish and shellfish samples, at levels less than 2% of the total arsenic. The study provides information about a possible distribution pattern of arsenic species in seafood products.
A selective, reliable and rapid method for the simultaneous determination of progesterone and norgestrel concentration in human serum after taking oral contraceptive tablet has been developed using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) with atmospheric pressure chemical ionization (APCI) interface. The norethisterone was used as the internal standard. Selected transitions of m/z 313/245 for norgestrel, m/z 315/97 for progesterone and m/z 299/109 for norgestrel were monitored using multiple reaction monitoring (MRM) mode for quantitation. The assay was linear over the concentration range of 0.2-50ng/mL for norgestrel and progesterone. The lower level of quantitation in human serum was obtained at 0.2ng/mL for both norgestrel and progesterone using optimum tuning parameters. Serum concentrations of norgestrel and progesterone were determined following oral administration of norgestrel to female volunteers.
