Food and Beverage Analysis

Mycotoxins, toxic secondary metabolites of several fungal species, represent food safety issues of high concern. Deoxynivalenol, the most abundant trichothecene mycotoxin, can be found worldwide as a contaminant of wheat, barley, maize and other cereals (1,2). The transmission of deoxynivalenol from barley into beer has been reported in several studies (3,4). Therefore, its levels should be controlled.

Supercritical fluid chromatography (SFC) is a normal phase separation technique. In SFC, supercritical CO2 in combination with one or more polar organic solvents, most commonly alcohols, is used as the mobile phase. Owing to the lack of intermolecular interactions, supercritical fluid typically possesses lower viscosity and higher diffusivity than those solvents used in traditional high performance liquid chromatography (HPLC). This allows for higher flow rates, faster analyses, and the use of longer columns for higher chromatographic efficiencies. Initially deemed a niche chromatographic technique for chiral separation, the horizon of SFC applications has rapidly expanded to include achiral analyses of natural products, biodiesel, oligomer, pesticides/herbicides, and peptides. This is due, in part, to the improvements in detection choices and performances for SFC. Evaporative light scattering detectors (ELSDs) coupled with SFC have found wide use in many pharmaceutical and chemical laboratories (1).

In March 2007, several North American manufacturers of pet food voluntarily issued nationwide recall notices for some of their products that were reportedly associated with renal failure in pets. The raw material wheat gluten, used to manufacture the pet food, was imported from China and was identified as the source of contamination.

Gel permeation chromatography (GPC) has been used as an effective cleanup procedure for removing high molecular weight interfering molecules such as lipids, pigments, proteins, and polymers before GC or HPLC analysis. The GPC cleanup method has been extensively documented (1–3) and is also recommended in US EPA SW-846 Method 3640A. To demonstrate the efficacy of this method to extract polar and nonpolar substances by using the KNAUER Smartline GPC Cleanup Unit 6500, olive oil samples were investigated by spiking these with different types of organic pollutants, including PAHs, phthalates, phenols, and triazine.

The natural colors of the food we eat add greatly to the enjoyment of life. Consequently, the art and science of recreating food's natural colors through the use of synthetic colorants is an important success factor in the food industry.

Labtronics has been pleased to announce that a leading food and beverage manufacturer has selected its Nexxis sample tracker to upgrade their existing in-house sample tests and result tracking system.

The potential of the time-of-flight mass spectrometry (TOF-MS) to innovate the analysis of soft drinks is described using gas chromatography (GC) hyphenated to TOF-MS and a new type of ion source, direct analysis in real time (DART), coupled to high-resolution TOF-MS. Head-space solid-phase microextraction (SPME) was used to isolate/extract volatile compounds followed by GC–TOF-MS to identify tainted compound in contaminated soft drinks. Direct analysis in real time–time-of-flight mass spectrometry (DART–TOF-MS) was also used to obtain negative and positive ion profiles of different soft drinks to determine the presence of various compounds, including antimicrobial preservatives, artificial sweeteners, acidulants and saccharides, without any sample preparation and chromatographic separation.

The determination of inorganic elements in food substances is critical for assessing nutritional composition and identifying food contamination sources. The inorganic elements of interest can be divided into two classes: nutritional and toxic. It is important to determine the levels of both sets of elements accurately to assess both the nutritional and the harmful impacts of food substances. Nutritional elements such as Mg, P, and Fe are present at high levels (milligrams per kilogram), while toxic elements such as Pb, Hg, and Cd should be present only at trace levels (nanograms or micrograms per kilogram).

A simple and inexpensive sample preparation method followed by reversed-phase high performance liquid chromatography (RP-HPLC) was developed to quantify oxytetracycline (OTC), chlortetracycline (CTC), and tetracycline (TC) residues in prawns. The total analytical time, including sample preparation, was 15 min for each sample and no organic solvents were used in the sample preparation or chromatography stages.

Well, it's Pittcon Day 2, and I followed the suggestion of LCGC Columnist John Hinshaw and attended session 410, "Food Science: UV-Vis, NIR, AA, LC, GC, and Electric Nose."

The techniques involved in successfully separating and quantifying amino acids vary from instrument to instrument. However, the processes for amino acid analysis are similar, involving hydrolysis, labeling, separation, and detection followed by data analysis.

The authors use GPC coupled online to multiangle laser light scattering, refractive index, and ultra violet (UV) detectors for the characterization of Acacia gum (gum arabic).

The flavours of malt whisky result from a complex blend of long chain esters and alcohols, derived from the distillation products and the composition of the wooden barrels in which the finished product is aged. As shown below, the new VF-WAXms column from Varian, Inc. is ideal for analysing whisky, especially when trace analysis is needed. The column's ultra-low bleed increases sensitivity, extends column life and improves accuracy, even at higher temperatures. In addition, VF-WAXms columns are suitable for use with MS detectors, as the ultra low bleed eliminates interferences and permits more sensitive detection.

Calvados is an apple-brandy of Normandy (France). Mashed apples are fermented to obtain cider, which is then distilled to give the young spirit.

Liquid chromatography–mass spectrometry (LC–MS) is a popular technique for the analysis of wine. This article gives an overview of wine analysis and new insights this technique has revealed regarding the composition of wine, possible health benefits, customer safety and the understanding of winemaking processes.

This month's instalment of "Sample Prep Perspectives" describes a new extraction technique called QuEChERS (standing for quick, easy, cheap, effective and safe and is pronounced "catchers") for the sample preparation of pesticides in foods and agricultural samples. The technique uses simple glassware, a minimal amount of organic solvent and various salt/buffer additives to partition analytes into an organic phase for clean up by dispersive solid-phase extraction (d-SPE). The technique provides good recoveries, is reproducible and costs less than other sample preparation approaches. The technique is being adopted by many laboratories worldwide. It has the potential for applications outside of the pesticide in foods area.

The determination of the carcinogenic food processing contaminant furan by headspace sampling of foods is challenging because it can easily escape from the sample during preparation. Furan can also be easily formed as a by-product when the sample is heated in the headspace apparatus. This article describes a number of approaches to overcome these difficulties and alternative methods to quantify furan in a variety of matrices.

Science Daily, a website that features news revolving around the sciences, has published an article that describes new chromatographic techniques for the analysis of pesticides and antibiotics in food and beverage samples.

The Montreal Gazette published an article about the use of analytical techniques in the wine industry. The author discusses the difference between "natural" wines and "industrial" wines that are created with a certain taste profile in mind and with the assistance of gas chromatography.

A Deans switch, employing Agilent's Capillary Flow Technology, was configured on an Agilent 7890A GC equipped with dual ECD detectors. A method was developed for the analysis of fish oil for PCB contamination. The Deans switch was used to heart cut 7 indicator PCBs (IUPAC Numbers 28, 52, 101, 118, 138, 153 and 180) from the primary DB-XLB column on to a DB-200 column for further separation. Fish oil from a supplement capsule was simply diluted 1:10 in isooctane and injected directly. To prevent carryover, contamination and retention time shifts, the Deans switch was used to backflush the primary column at the end of each run.

This article describes the development of a routine method to analyse epoxidized soybean oil (ESBO) in baby food...

A fast quantitation method for the analysis of N-Methyl Carbamate pesticide residues in vegetables and grains has been developed. High recoveries were obtained for most carbamates screened in all matrices tested at 1 ppb levels. Good linearity of the calibration curves was observed for all analytes, over the range from 1 ppb to 200 ppb levels, with r2 greater than 0.99.

Scientists from the Federal Institute for Materials Research and Testing, Department of Analytical Chemistry have derived a new way to test for Ochratoxin A (OTA) in beer.

Phenomenex, Inc., a global leader in the separation sciences business, has been notified by R&D Magazine that it has won the coveted R&D 100 Award for the second year in a row.

James Morphet and Peter Hancock Waters Corporation, Manchester, UK

Very low level detection of mycotoxins in the agriculture products has become increasingly important. Mycotoxins are very resistant fungal metabolites that can remain in foods after processing and, sometimes, even after cooking. They are considered potent carcinogens and can be found in many varieties of foods. Of the mycotoxin class, aflatoxins are considered especially harmful, being both acutely and chronically toxic. Aflatoxin B1 and B2 are some of the most potent hepatocarcinogens known. Along with aflatoxins G1 and G2, even extremely low levels of these aflatoxins in the diet are important public-health concerns. With this in mind, this application note describes a specific, robust HPLC method for the low-ppb detection of aflatoxins B1, B2, G1 and G2 in corn.

This month's installment of "Sample Prep Perspectives" describes a new extraction technique called QuEChERS (standing for quick, easy, cheap, effective, and safe and is pronounced "catchers") for the sample preparation of pesticides in foods and agricultural samples.

This article describes the development of a routine method to analyse epoxidized soybean oil (ESBO) in baby food based on a previous method devised by Castle et al. The aim was to simplify the work-up procedure to reduce the strain on the analytical equipment. The extraction procedure was miniaturized to improve handling, reduce the resources needed and simplify the method. After derivatization, the extracts were cleaned using gel permeation chromatography (GPC). A modified gas chromatography mass spectrometry (GC–MS) method using pulsed splitless injection was developed to determine the analyte. For quality control (QC), peak area ratios (PARs) were calculated and evaluated in terms of functionality under routine conditions. The method was validated according to EU regulations at a level of 20 ppm and showed high reproducibility. The miniaturized method proved to be applicable to all investigated baby food matrices and demonstrated the benefits of a GPC clean-up step to reduce strain on the..

Pesticide contamination of foodstuffs has become a worldwide concern, prompting various levels of regulation and monitoring. Traditionally, pesticides are quantified with gas chromatography (GC) combined with selective detectors (ECD, FID, etc.). Selective GC detectors are great tools to quantify one or two classes at a time. However, screening for a number of different classes of pesticides requires multiple runs utilizing various GC configurations to achieve sufficient chromatographic resolution for unambiguous quantification. Gas chromatography–mass spectrometry (GC–MS) provides positive confirmation of various pesticides in a single analytical run because its superior selectivity allows interference-free quantification even with peak coelution. GC–MS has become a preferred technique for pesticide analysis because of its single-run capability.