Quantifying Residues from Postharvest Propylene Oxide Fumigation of Almonds and Walnuts.

A novel analytical approach involving solvent extraction with methyl tert-butyl ether (MTBE) followed by GC was developed to quantify residues that result from the postharvest fumigation of almonds and walnuts with propylene oxide (PPO). Verification and quantification of PPO, propylene chlorohydrin (PCH) [1-chloropropan-2-ol (PCH-1) and 2-chloropropan-1-ol (PCH-2)], and propylene bromohydrin (PBH) [1-bromopropan-2-ol (PBH-1) and 2-bromopropan-1-ol (PBH-2)] was accomplished with a combination of electron impact ionization MS (EIMS), negative ion chemical ionization MS (NCIMS), and electron capture detection (ECD). Respective GC/EIMS LOQs for PPO, PCH-1, PCH-2, PBH-1, and PBH-2 in MTBE extracts were [ppm (µg/g nut)] 0.9, 2.1, 2.5, 30.3, and 50.0 for almonds and 0.8, 2.2, 2.02, 41.6, and 45.7 for walnuts. Relative to GC/EIMS, GC-ECD analyses resulted in no detection of PPO, similar detector responses for PCH isomers, and >100-fold more sensitive detection of PBH isomers. NCIMS did not enhance detection of PBH isomers relative to EIMS and was, respectively, approximately 20-, 5-, and 10-fold less sensitive to PPO, PCH-1, and PCH-2. MTBE extraction efficiencies were >90% for all analytes. The 10-fold concentration of MTBE extracts yielded recoveries of 85-105% for the PBH isomers and a concomitant decrease in LODs and LOQs across detector types. The recoveries of PCH isomers and PPO in the MTBE concentrate were relatively low (approximately 50 to 75%), which confound improvements in LODs and LOQs regardless of detector type.

Mollenynes B-E from the marine sponge Spirastrella mollis. Band-selective heteronuclear single quantum coherence for discrimination of bromo-chloro regioisomerism in natural products.

Four new chlorobromohydrins, mollenynes B-E, were isolated from the marine sponge Spirastrella mollis collected from Hogsty Reef, Bahamas. Their structures were elucidated by integrated analysis of NMR, MS, and computational methods. A high-resolution band-selective HSQC experiment was developed to identify (13)C NMR signals in samples at the nanomole-scale that arise from Cl-substituted (13)C by exploiting the (35)Cl/(37)Cl isotope shift.

Trace detection of the chlorohydrins of epoxidized soybean oil in foodstuffs by UPLC-ESI-MS/MS.

Epoxidized soybean oil (ESBO) is used as an authorized plasticizer and a stabilizer for plastic polymers such as poly(vinyl chloride) (PVC). Recently, however, there has been a concrete effort devoted to its substitution for other plasticizers such as polyadipates. ESBO is exploited particularly in food closure gaskets for metal lids used to seal glass jars and bottles. The closure gaskets form an airtight seal necessary to prevent microbiological contamination. Thus, there are potential uses for food sterilization and storage. Additionally, the main pathway of PVC degradation involves the elimination of HCl, which can react with the epoxy groups of ESBO to give mono-, polychlorohydrins and/or other cyclic derivatives. The European Food Safety Authority noted that not enough analytical and toxicological data exist to express a formal opinion on the significance for the health effects of such derivatives. At present in the scientific literature, there are only a few indicative results of direct measurements of ESBO derivatives and there are no official analytical methods available for the determination of chlorohydrins directly from foodstuffs. This study presents the first example of the analysis of commercial food sauces for the detection of ESBO-chlorohydrins (as methyl esters). The results are obtained by a dedicated development of an ultraperformance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) method. Sample preparation was based on the following main steps: organic extraction, transesterification and solid-phase extraction clean up. In particular, four isomers for 18-E-OHCl chlorohydrin and eight isomers for 18-2OHCl chlorohydrin were separated and identified. Different food sauces samples closed in glass jars with twist-off caps were subjected to qualitative determination, which yielded positive results for 18-E-OHCl, whereas no traces of 18-2OHCl were found.

[Markers of chloric acid (I) in biological systems--identification and properties]. / Markery kwasu chlorowego (I) w ukladach biologicznych--identyfikacja i wlasciwosci.

Reactive oxygen and nitrogen species are attributed to initiation and propagation of many diseases. The demonstration of elevated activity of myeloperoxidase and the level of 3-chlorotyrosine in atherosclerosis, kidney diseases and chronic inflammations brought about the interest in the biological role of another strong oxidant--hypochlorite. Concentration of this compound is extremely difficult to estimate in vivo and in vitro because of its high reactivity. The reaction of hypochlorite with biological compounds lead to formation of chlorohydrins, glutathione sulfonamides, chloramines, 3- and 3,5-dichlorotyrosines and chlorinated DNA bases (8-chloroadenine, 8-chloroguanine, 5-chlorocytosine and 5-chlorouracil). At least some of these products of hypochlorite action are believed to provide specific HOCl-biomarkers, useful especially in the analysis of clinical samples, using sensitive detection techniques.

Isolation and identification of terpene chlorohydrins found in cold-pressed orange oil.

Three terpene chlorohydrins found in cold-pressed orange oil were concentrated by silica adsorption chromatography and purified by preparative HPLC. Formation of these chlorohydrins was determined to be the result of a reaction of d-limonene, the major component of cold-pressed oil, with hypochlorous acid, found in chlorinated treatment water used in the oil recovery process. NMR analyses indicated that the major chlorohydrin present was the diequatorially substituted (1R,2R,4R)-2-chloro-8-p-menthen-1-ol (1). The other two compounds were the diaxial trans stereoisomer, (1S,2S,4R)-2-chloro-8-p-menthen-1-ol (2), and the dichlorohydrin, (1R,2R,4R)-2,9-dichloro-8-p-menthen-1-ol (3).

Chlorosilphanol A and silphanepoxol, labdane diterpenes from Silphium perfoliatum.

Two carterochaetols, chlorosilphanol A and silphanepoxol, isolated from the leaves of Silphium perfoliatum were assigned structures 1 and 3, respectively, from spectral studies and with absolute stereochemistry established by X-ray crystallography of 1. Complete 1H- and 13C-nmr assignments for the parent compounds and their acetates 2 and 4 were made at high-field using 1D and 2D methods, and chlorosilphanol A was chemically converted via its acetate to silphanepoxol. Revision of structure for related carterochaetols in the literature is required, in particular with respect to the stereochemistry at C-12 and that of the side-chain.

Chromatographic resolution of chiral intermediates in beta-adrenergic blocker synthesis on chiral stationary phases.

The enantiomeric purities of optically active intermediates for beta-adrenergic blocking agents prepared via enzyme-assisted processes can be determined rapidly and with high accuracy using HPLC on commercially available columns with chiral supports [Chiralcel OD, OB; Chiralpak OT(+)]. The dependence of the resolution parameters on the substitution pattern of both hydroxy compounds and their esters is reported.

Stereospecific analysis of fatty acid esters of chloropropanediol isolated from fresh goat milk.

The fatty acid esters of chloropropanediol isolated from goat milk fat in small quantities were subjected to a stereospecific analysis via phospholipase C and phosphocholine esters as intermediates. Synthetic rac-1-chloro-2,3-dioleoyl-propanediol was prepared by standard methods and was used as a control. The stereospecific analyses were performed following a release of the fatty acids from the primary positions of each chloropropanediol diester with pancreatic lipase. The resulting X-1-chloro-2-acylpropanediols were then converted into the corresponding phosphocholine derivatives by a stepwise reaction with phosphorus oxychloride and choline chloride. The X-1-chloro-2-acyl-3-phosphocholinepropanediols were subjected to hydrolysis with phospholipase C (C. perfringens), which hydrolyzed 50% of the phosphatide within two min and the rest of it in two hr. From previous experience with glycerol esters, it was assumed that the more rapidly hydrolyzed molecules were the sn-1-chloro-2-acyl-propanediol derivatives and the more slowly hydrolyzed ones the sn-2-acyl-3-chloropropanediol derivatives. A hydrolysis with phospholipase A2 (Crotalus adamanteus) released 50% of the total fatty acid along with the corresponding lyso compound within 10 min, after which there was no further reaction. The hydrolysis products were assayed directly by gas liquid chromatography (GLC) or were isolated by thin layer chromatography (TLC) prior to quantitation by GLC. Both naturally occurring and synthetic chloropropanediol diesters behaved similarly on stereospecific analysis and were therefore concluded to be racemic.