food & beverage
21 Issue 2 2020
Thermometry – the better method to determine total sodium in foodstuffs
A
commonly used method for quantifying sodium in foodstuffs is to determine the counter-ion chloride using argentometric titration, the concentration of which can be used to deduce the sodium concentration from the 1:1 stoichiometry of sodium chloride. This method involves errors because sodium is not only present with chloride as the counter-ion. A new method for direct titration of sodium with thermometric endpoint detection solves this problem. Thermometric titration shares with potentiometric titration the use of a sensor to detect the endpoint of the titration reaction. In the case of thermometric titration, however, the sensor is a fast responding thermometer. Hence, instead
of measuring the electrochemical potential in the solution, this robust, highly sensitive thermometer tracks the reaction enthalpy, i.e. the temperature change in the solution. The endpoint of the titration is marked precisely by the moment, when the reaction stops and no significant temperature change is registered any longer in the solution. Because it relies merely on a change of solution temperature to find the endpoint, there is no need to calibrate the sensor. Sensor maintenance is minimal, and it can be stored dry between titrations. As for sample preparation, users only need to ensure that
the matrix does not prevent the analyte from reacting with the titrant and that the sample is sufficiently mobile.
METROHM SA (PTY) LTD Tel: (011) 656 1918 CPT: (021) 852 0213 DBN: (031) 265 0067 Fax: (011) 656 2698 078 643 7113 info@metrohm.co.za www.metrohm.co.za
Lateral flow reader for fast mycotoxin detection
V
ICAM, a Waters Business, offers the Vertu™ digital lateral flow reader for fast, easy, and quantitative mycotoxin screening. The Vertu reader provides accessible mycotoxin testing to food and agriculture producers that rely on early detection to protect humans and animals from contamination. The Vertu system is easy to use and allows one to test at the point of sampling, offering exceptional value with fast, accurate numerical results, using fewer solvents in less time. The Vertu lateral flow reader is designed to analyse Vicam lateral flow strip tests. The optical detector moves
along the strip test, records data and converts the data to a toxin concentration through a lot-specific calibration curve. Digital readings are clearly displayed on the screen eliminating any guesswork. Operators obtain results in part-per-billion (ppb) or part-per-million (ppm)
Accurate results are available in less than two minutes. Metrohm provides the 859 Titrotherm with tiamo software for thermometric titrations, a total solution that can easily be automated by integrating an autosampler. Thermometric titration and its application to food samples is described in detail in a Metrohm whitepaper, which can be found on this link: https://bit.ly/2SMqupZ.
in minutes, providing critical data for the management and control of mycotoxins, either onsite or in the laboratory. Vertu technology enhances VICAM’s portfolio of single-use food safety tests designed to detect contaminants in ppb. It meets increasingly stringent regulatory and economic challenges confronting today’s global food chain. With a comprehensive product line evaluated and trusted by industry leaders in more than 100 countries, VICAM is the leader in rapid mycotoxin test solutions. Mycotoxins are naturally occurring chemical byproducts of ubiquitous mould species that are natural inhabitants of crop soils. Severe rain or drought can encourage
mycotoxin production. Once released, mycotoxins are difficult to manage and virtually impossible to destroy. VICAM offers detection systems for single and multiple mycotoxin quantification both onsite and in-laboratory screening. Producers and exporters use onsite testing to ensure regulatory compliance and to protect human and animal health.
MICROSEP (PTY) LTD Louis van Huyssteen Tel: (011) 553 2300 Fax: (011) 553 2400 louis.vanhuyssteen@microsep.co.za www.microsep.co.za
Büchi Kjeldahl modular flexibility for protein/nitrogen determination
B
üchi’s range of KjelFlex K-360 digestion and additional steam distillation instruments can be matched to individual or changing needs at any time. By means of add-on modules the customer can adjust the K-360 according to each individual application – before or after purchase. These state-of-the-art units provide accurate and highly reproducible results with an excellent recovery rate. It can be used for a variety of applications in analytical laboratories in food and beverage, feed, agricultural, environmental, chemical and pharmaceutical industries. In addition to the traditional applications (Kjeldahl, Devarda, TKN), the K-360 can be used for an extended range of accepted distillation methods, including those with regulated steam output or requiring the dosage of strong acids. Examples include alcohol- and phenol distillation and the determination of formaldehyde content, sulphur dioxide and volatile acids. These and many other applications are available free upon request from Labotec, Büchi’s representative in southern Africa. The design of the splash protector is a
crucial factor in getting highly reliable analytical results, when determining protein or nitrogen according to the Kjeldahl method. With the K-360 Büchi offers a choice of two splash protector types: the standard version in glass or plastic. The glass edition features a transparent distillation zone for easy visual monitoring. The basic configuration provides automatic dosage of boric acid, NaOH and water as standard. If needed, the unit can be equipped with an additional acid-resistant pump for the dosage of stronger acids. The application range is extended by a number of non-Kjeldahl applications, such as phenol distillation and the determination of formaldehyde content, sulphur dioxide and volatile acids. By connecting an external titrator, the K-360 capabilities are extended to provide an automatic system for nitrogen and protein determination. With this configuration, manual, labour and human error is reduced to an absolute minimum, as the titration will start automatically when the distillation is finished. After titration the contents of the sample tube and receiving vessel are drawn off automatically and discarded into waste.
Besides its unique modularity, the new K-360 also offers additional features such as: storage capacity of up to 50 customerspecific methods or 500 results, password security, data printout using a USB interface, multilingual software, and numerous safety functions.
LABOTEC (PTY) LTD JHB: (011) 315 5434 CPT: (021) 531 7660 DBN: (031) 566 4870 Fax: (011) 315 5882 sales@labotec.co.za www.labotec.co.za
