Daniel J. Ehntholt

Migration of BHT and Irganox 1010 from low-density polyethylene (LDPE) to foods and food-simulating liquids.

The most widely used food-wrapping material is low-density polyethylene (LDPE). Food-wrap grades contain antioxidants to minimize degradation during processing and, in the final films, such additives are normally present at levels of several hundred ppm. During use, the antioxidants may migrate into food stored in LDPE wraps. Two typical antioxidants, BHT and Irganox 1010, were radiolabelled to allow accurate analytical measurement of the extent of their migration into foods and food-simulating liquids (FSL). The results show that BHT, a much smaller and more volatile molecule than Irganox 1010, migrates more rapidly into foods, but the differences are less for FSL. In most instances, migration appears to be controlled by diffusion of the antioxidant in the polymer, and the quantity lost can be correlated in a linear fashion with the square root of time. With aqueous FSL, and, presumably aqueous-type foods, however, anomalies result; the migration is often erratic, but is more closely related to time than to the square root of time. A tentative model developed to explain these facts assumes that the antioxidants decompose in aqueous media and the net migration rate is controlled largely by the rate of chemical decomposition. It is also shown that dry foods can be surprisingly effective sinks for antioxidants under typical storage conditions.

Indirect Food Additive Migration from Polymeric Food Packaging Materials

Many foods contact polymeric packaging materials which contain residues of the polymerization process or additives employed to facilitate processing. The extent of migration of such materials from the packaging to foods is the focus of the present article. A major experimental program using eight polymer-migrant systems is described. Migration was measured to food-simulating liquids (FSL) and to foods. Accelerated tests were conducted with FSL under FDA guidelines conditions so as to develop correlations between such data and those found using foods under normal storage temperatures and shelf lives. In the majority of tests, the migration was found to be approximately proportional to the square root of time, to increase significantly with a rise in temperature, and to be proportional to the initial concentration of migrant in the polymer. Stirring in the FSL or food phase was generally not important except for the system involving dioctyl adipate migrating from polyvinyl chloride film. In some instances, after a period of time, migration rates became very low, and this effect was attributed to saturating the FSL or food phase with migrant. The foods comprised a variety of types, including liquid, semisolid, solid, and dry; both oily and aqueous foods were included. The physical steps involved in migration include the diffusion of the migrant from the interior of the film to the surface, where it can dissolve in the external FSL or food phase. The nature of the FSL or food is shown to be very important in that components can penetrate the polymer and dramatically increase migration rates. Consistent with the FDA guidelines in effect at the time of this study, testing was performed with five FSL (water, 3% acetic acid, 8% and 50% ethanol, and n-heptane) at 49 degrees C. Detailed comparisons were made between the migrations to foods and to FSL; following are the more relevant conclusions. (1) Three percent acetic acid showed no advantage over water as a food simulant even in those cases where the food could be considered acidic in nature. (2) Water, when used as an FSL at 49 degrees C for 5 days, overestimated migration in aqueous foods in about 75% of the cases. In some instances, however, the water phase became saturated with migrant. In other situations, this test protocol underpredicted migration--especially in those cases where there were components in the food that were able to penetrate into the polymer and enhance migration (such as orange juice).(ABSTRACT TRUNCATED AT 400 WORDS)

A Test Method for the Evaluation of Protective Glove Materials Used in Agricultural Pesticide Operations

The ASTM Standard Test Method for Resistance of Protective Clothing Materials to Permeation by Liquids and Gases (F 739-85) and the recommended permeation cell have been modified to permit the testing of protective clothing materials for permeation by the low volatility, low water solubility active ingredients present in many pesticide formulations. The modification makes use of solid collection medium, a thin (0.02-in. thick) sheet of silicone rubber, to collect permeants. Those compounds permeating the protective material can then be desorbed into an appropriate solvent and analyzed using conventional methods and instruments. A series of permeation tests have been conducted using samples of 10 common, commercially available protective glove materials and the modified cell. Permeation of the active ingredient as well as carrier solvent components of several concentrated pesticide formulations containing low volatility, low water solubility active ingredients and aromatic hydrocarbon carrier solvents has been monitored. The relative breakthrough and the total mass of material permeating the glove materials appears to be strongly related to the concentration of the aromatic carrier solvent present in the formulations studied to date. The collection method was found to be less useful for monitoring the permeation of active ingredients, which have reasonably high water solubilities. The results obtained by using this method with samples of protective glove materials challenged by several concentrated pesticide formulations are described. For these formulations containing xylene boiling range aromatic solvents, gloves made of nitrile rubber, butyl rubber, and Silver Shield were most resistant to permeation; natural rubber and polyethylene glove materials were least resistant.

PERMEATION RESISTANCE OF GLOVE MATERIALS TO AGRICULTURAL PESTICIDES

The toxicities of many agricultural pesticides require that hand protection be used by persons who mix, load, and apply these products, as specified on the label and material safety data sheet. Selection of gloves for formulations that contain organic solvents is particularly problematic because a solvent that permeates the glove can carry with it the active ingredient of the pesticide formulation. With a test method that measures the simultaneous permeation of the carrier solvent(s) and active ingredient(s), in particular those active ingredients that have low solubility in water and low volatility, over 100 permeation tests (in triplicate) with approximately 20 pesticide formulations were conducted with 13 different glove materials. These results are summarized and generalizations are presented within the perspective of the large base of permeation data for neat chemicals and another large permeation study with pesticides. Key among the findings is that the carrier solvent generally permeates first and at a much higher rate than the active ingredient. Furthermore, the permeation behavior of formulations containing solvents generally mirrored that of neat carrier solvents alone. Thus, insight into the selection of the most appropriate glove material for a given pesticide formulation can be gained from permeation data for neat chemicals. For the types of solvents that may be present in pesticide formulations, preferred materials include nitrile rubber, butyl rubber, and plastic film laminates. Natural rubber and polyvinyl chloride materials generally are not recommended.

Migration of Irganox 1010 from ethylene-vinyl acetate films to foods and food-simulating liquids

In a series of experiments on the migration of the antioxidant Irganox 1010 from ethylene-vinyl acetate (EVA) films into food-simulating liquids and foods, the antioxidant was found to migrate rapidly from EVA film into n-heptane, 100% ethanol and corn oil. The rate of migration into these media was greater from EVA than from low-density polyethylene (LDPE) under comparable conditions. In contrast, little migration of Irganox 1010 was recorded on exposure of the EVA film to aqueous media, whereas migration from LDPE into such media was relatively high.

A volatile organics concentrator for use in monitoring Space Station water quality

The process used to identify, select, and design an approach to the isolation and concentration of volatile organic compounds from a water sample prior to chemical analysis in a microgravity environment is discerned. The trade analysis leading to the recommended volatile organics concentrator (VOC) concept to be tested in a breadboard device is presented. The system covers the areas of gases, volatile separation from water, and water removal/gas chromatograph/mass spectrometer interface. Five options for potential use in the VOC and GC/MS system are identified and ranked, and also nine options are presented for separation of volatiles from the water phase. Seven options for use in the water removal/GC column and MS interface are also identified and included in the overall considerations. A final overall recommendation for breadboard VOC testing is given.

Design and development of a personal alarm monitor for use by first responders

This paper describes the design and development of a small, portable alarm device that can be used by first responders to an emergency event to warn of the presence of low levels of a toxic nerve gas. The device consists of a rigid reusable portion and a consumable packet that is sensitive to the presence of acetylcholinesterase inhibitors such as the nerve gases Sarin or Soman. The sensitivity level of the alarm is set to be at initial physiological response at the meiosis level, orders of magnitude below lethal concentrations. The AChE enzyme used is specific for nerve-type toxins. A color development reaction is used to demonstrate continued activity of the enzyme over its twelve-hour operational cycle.

The development and testing of a volatile organics concentrator for use in monitoring Space Station water quality

The Volatile Organics Concentrator (VOC) system, designed to attach to a gas chromatograph/mass spectrometer (GC/MS) for the analyses of volatile organic compounds in water on Space Station Freedom, is described. Organic volatiles are collected and concentrated in the VOC by means of two primary solid sorbent tubes and desorbed into the GC/MS system. The paper describes the results of testing the VOC breadboard using a GC/MS system. Evaluations performed on 39 organic compounds recovered from water samples were compared with data for these compounds using direct injection/GC/MS and purge and trap/GC/MS procedures. The results demonstrate that the VOC/GC/MS systems detection limits for the 39 compounds analyzed are comparable to those of the EPA Method 524.2, and for many compounds reaching a factor of 5 lower.

The Development of a Volatile Organics Concentrator for Use in Monitoring Space Station Water Quality

A breadboard concept of a volatile organics concentrator (VOC) is manufactured and tested for optimized water-quality analysis in a space environment. The VOC system is attached to a gas chromatograph/mass spectrometer to analyze the volatile chemicals relevant to the operation of Space Station Freedom. The preliminary tests include: (1) comparisons with analyses based on direct on-column injections of standards; (2) analyses of iodinated volatile organics; (3) comparisons of nitrogen vs helium as the chromatography carrier gas; and (4) measurements of collection efficiency. The VOC can analyze EPA method-624 analytes at comparable detection using flame-ionization detection and can analyze volatile iodinated compounds. The breadboard has good reproducibility and can use nitrogen as a carrier gas; good results are noted for the collection and concentration levels and for water removal.

Control of off-flavor compounds in aluminum can production

Abstract Aluminum cans have intermittently been associated with the development of off-flavors in beverages. Certain organic compounds, e.g., aldehydes and ketones, are known to contribute to flavor defects; trans -2-nonenal can be detected at 0.1 μg l −1 levels by trained tasters. In a recent study, the production process used to form two-piece aluminum cans was examined. Samples of aluminum coil stock, partly formed cans and finished cans were obtained from typical production lins and examined by a flavor panel and by chromatographic and spectroscopic methods in an effort to develop routine techniques for monitoring can production. Capillary-column gas chromatography and, after derivatization with dinitrophenylhydrazone, high-performance liquid chromatography are useful for quantifying off-flavor compounds and precursors in lubricants and other materials used in rolling mills and can-making operations, but are not adaptable to on-line monitoring. Correlations between gas-chromatographic data and flavor panel assessments were good.