Migration of Contaminants from Milk Tubes and Teat Liners

The survey tested migration of contaminants from various flexible tubes and teat liners used in milk production. A total of 19 samples were analyzed through sensory evaluation and in migration tests with different simulant liquids. Plasticizers were dissolved in diethyl ether or tetrahydrofuran and analyzed in high performance liquid chromatography (HPLC). The most widely used polyvinyl chloride (PVC) tubes contained 37–40% di-2-ethylhexyl phthalate (DEHP) as plasticizer. In some tubes DEHP was to a great extent replaced by a polymeric plasticizer. DEHP was analyzed with reverse phase HPLC directly from milk in a procedure in which a piece of tube was soaked in milk for 1, 3 and 6 d. Tubes containing polymeric plasticizer lost less DEHP into milk, but relatively more than the tubes plastieized only by DEHP. The evaporation residue for migration tests to water was significantly greater for polyadipate tubes compared with tubes plastieized only by DEHP. The evaporation residue from the water extract of the tubes plastieized by polymeric plasticizer was by mass-speetral analysis found to consist of various hydrolyzation products of polyester from 1,3-butandiol and adipic acid. The results obtained are discussed in the light of toxieologieal problems connected with plasticizers.

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A novel pituitary protein (7B2)-like immunoreactivity is secreted by a rat phaeochromocytoma cell line (PC12)

Journal of Endocrinology ◽

10.1677/joe.0.1080151 ◽

1986 ◽

Vol 108 (1) ◽

pp. 151-155 ◽

Cited By ~ 7

Author(s):

H. Suzuki ◽

A. S. Tischler ◽

N. D. Christofides ◽

M. Chretien ◽

N. G. Seidah ◽

...

Keyword(s):

High Performance Liquid Chromatography ◽

Liquid Chromatography ◽

Cell Line ◽

Pc12 Cell ◽

High Performance ◽

Gel Permeation Chromatography ◽

Reverse Phase Hplc ◽

Reverse Phase ◽

Gel Permeation ◽

High Concentrations

ABSTRACT High concentrations of a novel pituitary protein (7B2) have been shown to be present in the PC12 rat phaeochromocytoma cell line by radioimmunoassay. 7B2-like immunoreactivity (IR-7B2) was released from PC12 cells into the incubation medium in response to stimulation by a depolarizing concentration of K+, and this K+-evoked release was inhibited by Co2+, The major IR-7B2 in PC12 cell and medium appeared to be identical to that in porcine pituitary gland as judged by both gel permeation chromatography and by reverse-phase high performance liquid chromatography (HPLC). Gel permeation chromatography of extracts of cell and medium revealed two IR-7B2 peaks, the earlier eluting at a elution coefficient (Kav) of 0·30 and the later at a Kav of 0·54. In medium, over 90% of the IR-7B2 eluted as the earlier peak. Fractionation of extracts of cell and medium on reverse-phase HPLC showed three main IR-7B2 peaks eluting at 43, 44·5 and 46% acetonitrile/water with 0·1% trifluoroacetic acid. The findings suggest that IR-7B2 might be released by calcium-mediated exocytosis. J. Endocr. (1986) 108, 151–155

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Chiral Separation and Determination of Etoxazole Enantiomers in Vegetables by Normal-Phase and Reverse-Phase High Performance Liquid Chromatography

Molecules ◽

10.3390/molecules25143134 ◽

2020 ◽

Vol 25 (14) ◽

pp. 3134

Author(s):

Ping Zhang ◽

Yuhan He ◽

Sheng Wang ◽

Dongmei Shi ◽

Yangyang Xu ◽

...

Keyword(s):

High Performance Liquid Chromatography ◽

Liquid Chromatography ◽

Chiral Separation ◽

Mobile Phase ◽

High Performance ◽

Normal Phase ◽

Reverse Phase Hplc ◽

Reverse Phase ◽

Normal Phase Hplc ◽

Chiralpak Ic

The chiral separation of etoxazole enantiomers on Lux Cellulose-1, Lux Cellulose-3, Chiralpak IC, and Chiralpak AD chiral columns was carefully investigated by normal-phase high performance liquid chromatography and reverse-phase high performance liquid chromatography (HPLC). Hexane/isopropanol, hexane/n-butanol, methanol/water, and acetonitrile/water were used as mobile phase at a flow rate of 0.8 mL/min. The effects of chiral stationary phase, mobile phase component, mobile phase ratio, and temperature on etoxazole separation were also studied. Etoxazole enantiomers were baseline separated on Lux Cellulose-1, Chiralpak IC, and Chiralpak AD chiral columns, and partially separated on Lux Cellulose-3 chiral column under normal-phase HPLC. However, the complete separation on Lux Cellulose-1, Chiralpak IC, and partial separation on Chiralpak AD were obtained under reverse-phase HPLC. Normal-phase HPLC presented better resolution for etoxazole enantiomers than reverse-phase HPLC. Thermodynamic parameters, including ΔH and ΔS, were also calculated based on column temperature changes from 10 °C to 40 °C, and the maximum resolutions (Rs) were not always acquired at the lowest temperature. Furthermore, the optimized method was successfully applied to determine etoxazole enantiomers in cucumber, cabbage, tomato, and soil. The results of chiral separation efficiency of etoxazole enantiomers under normal-phase and reverse-phase HPLC were compared, and contribute to the comprehensive environmental risk assessment of etoxazole at the enantiomer level.

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Advanced use of high-performance liquid chromatography for synthesis of controlled metal clusters

Nanoscale ◽

10.1039/c4nr01144a ◽

2014 ◽

Vol 6 (14) ◽

pp. 7889-7896 ◽

Cited By ~ 33

Author(s):

Yoshiki Niihori ◽

Miku Matsuzaki ◽

Chihiro Uchida ◽

Yuichi Negishi

Keyword(s):

High Performance Liquid Chromatography ◽

Liquid Chromatography ◽

Mobile Phase ◽

High Performance ◽

Metal Clusters ◽

Separation Method ◽

Reverse Phase Hplc ◽

Reverse Phase

This study reveals the advanced use of a separation method of metal clusters protected with two kinds of ligands, which involves a combination of reverse-phase HPLC and mobile-phase substitution.

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