A one-week in situ intercomparison campaign was completed on the Rice University campus for measuring HCHO using three different techniques, including a novel optical sensor based on difference frequency generation (DFG) operating at room temperature. Two chemical derivatization methods, 2,4-dinitrophenylhydrazine (DNPH) and o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine (PFBHA), were deployed d...

Results from an intercomparison of several currently used in-situ techniques for the measurement of atmospheric formaldehyde (CH2O) are presented. The measurements were carried out at Bresso, an urban site in the periphery of Milan (Italy) as part of the FORMAT-I field campaign. Eight instruments were employed by six independent research groups using four different techniques: Differential Opti...

A simple, selective and sensitive electrochemical method is described for the determination of different aldehydes at glassy carbon electrode using electrochemical impedance spectroscopy (EIS). The measurements were performed after their derivatization with 2,4-dinitrophenylhydrazine (DNPH) in acidic medium. The impedance measurements were investigated in the frequency range from 100 mHz to 100...

We describe a specific enzymatic spectrophotometric method for ascorbic acid in serum or plasma. Samples are analyzed indirectly by measuring the absorbance at 593 nm of a reaction product, a complex of ferrous ion and 2,4,6-tris(2-pyridyl)-s-triazine (Fe2+-TPTZ). This product is formed by reduction of the corresponding ferric ion complex (Fe3+-TPTZ), which is nonspecifically reduced by various...

Excess formaldehyde (FA) provides a significant threat that causes irreversible damage to both the environment and human health, long-term FA emission from commercial leather products is problem. Therefore, help control content, we propose fluorescence-based method detect selectively using reaction-based probe FAP-1. Water-soluble FAP-1 was simply synthesized through two steps optical propertie...

After intravenous injection of S-adenosyl-L-homocysteine3H (homocysteine-labeled) into rats, less than 15% of the radioisotope was incorporated into protein methionine or excreted in the urine as oc-ketobutyrate. The remaining radioisotope was found associated with an unknown keto acid excreted in the urine. Intravenous injection of Sadenosyl-L-homocysteine-35S or S-adenosyl-3H-L-homocysteine (...

This noninvasive method for collection and analysis of a wide range of aldehydes and ketones in human breath may enable assessment of lipid peroxidation and metabolic status in vivo. Breath samples are drawn through silica cartridges impregnated with 2,4-dinitrophenylhydrazine, which traps carbonyls as their hydrazone derivatives. The hydrazone derivatives are eluted from the cartridges with ac...

Sphingosine 1-phosphate lyase (SPL) is responsible for the irreversible catabolism of sphingosine 1-phosphate, which signals through five membrane receptors to mediate cell stress responses, angiogenesis, and lymphocyte trafficking. The standard assay for SPL activity utilizes a radioactive dihydrosphingosine 1-phosphate substrate and is expensive and cumbersome. In this study, we describe an S...

The cortical cytoplasm of the developing oocyte of Rana pipiens has been investigated by cytochemical means. Particular emphasis is placed on the nature and distribution of polysaccharide protein complexes. With toluidine blue O, both living and fixed mature oocytes were found to possess a distinct metachromatic region just under the developing vitelline membrane. Younger oocytes, at the previt...