34 Environmental Analysis Measuring Bromate Photometrically, a Simple Method for Reliable Results


Water treatment methods are routinely used to ensure a safe drinking water supply. However, these processes can sometimes lead to unwanted side reactions that introduce compounds, such as bromate, into the water.


As a method for measuring bromate, ion chromatography has successfully been used, but it has some disadvantages. These include the high cost of the equipment and the complex procedure used to measure bromate. Co-elution of bromate with for example chloride can occur and this leads to interferences of the analysis. To circumvent this problem, special separation techniques can be used, such as a high-capacity anion exchanger or sample pretreatment.


Merck Millipore (Germany) has developed a method using photometry to measure bromate. The method is based on the reaction of 3,3'-Dimethylnaphtidin with iodide and bromate to produce a red radical cation, whose absorbance is determined photometrically. The more bromate contained in the sample, the more intense the color at the end of the reaction time.


Ion chromatography and photometry methods were compared using known standards as well as test samples. Measurements showed good agreement with the standards and with each other. The simplicity and low cost of using photometry make it a very desirable method for measuring bromate.


Using classical photometry, a calibration curve must first be done in order to determine the concentration of bromate in the unknown sample. Using a Merck Millipore Spectroquant® Pharo spectrophotometer, you can completely avoid the time consuming step of preparing a calibration curve. The Spectroquant® instruments are pre-programmed with a calibration curve for accurate determination of bromate levels in your sample from 0.003 – 0.120 mg/l.


The sample preparation and bromate analysis is described in a detailed application note from Merck Millipore. The sample is first concentrated for increased sensitivity, then mixed with reagents as specified in the application note. Sample is then incubated for 30 minutes to allow color development followed by bromate measurement using a Spectroquant® Pharo spectrophotometer.


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New Instrument for the Automated VOC Analysis of Air and Gas in Canisters


Markes International (UK) has announced the launch of a new instrument, the CIA Advantage™, designed for the VOC analysis of air and gas sampled using canisters. The CIA Advantage will be an invaluable tool for analytical chemists who measure VOCs in air samples using canisters. It is particularly well-suited to those using US EPA Method TO-15 and other methods involving an extended range of pollutants. The CIA Advantage offers scope for improving work-flow productivity and flexibility, and this, coupled with the additional functionality of sorbent tube analysis, makes it a unique instrument in its field.


Although canisters have traditionally been applied to ambient air analysis, in recent years they have been increasingly used for other applications, such as vapour intrusion and soil gas studies. Modern analytical systems for air monitoring applications are therefore now expected to manage a wider range of sample concentrations. To do this effectively on a


single analytical system, a new approach is required. The CIA Advantage from Markes International addresses this challenge.


“The CIA Advantage can analyse samples with a wide range of analyte concentrations, with the utmost confidence” says Matthew Bates, Product Manager at Markes International. He points out that “the CIA Advantage is fully compliant with US EPA Method TO-15, making it the ideal solution for laboratories wanting a robust, high-throughput system for canister air monitoring”.


The CIA Advantage can accommodate up to 27 canisters of various sizes, and operates completely cryogen-free, eliminating the cost of using liquid cryogen. All internal lines are heated to prevent cross-contamination of samples, and it uses patented technologies to prevent the ice formation that continues to be a frustration experienced by many proponents of US EPA Method TO-15.


An added benefit of the CIA Advantage, says Bates, is that it has inbuilt capacity to handle sorbent tubes. This, he says, “extends the range of compounds that can be analysed compared to canisters, allowing laboratories to offer the widest possible range of air-monitoring services”.


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On-Site TPH in Soil Measurements in Less Than 10-15 Minutes with Portable Infrared Analysers


On-site analysis of total petroleum hydrocarbon (TPH) concentration levels in soil are easily handled using the InfraCal TOG/TPH Analysers manufactured by Wilks Enterprise (USA). The InfraCal TOG/TPH Analysers are portable infrared (IR) analysers that quickly determine TPH levels in less than 10-15 minutes, including the extraction. Concentrations as low as 10 ppm to well over 10,000 - 20,000 ppm can be easily and accurately measured. Models are available for use with various extracting solvents such as S-316, hexane and perchloroethylene.


InfraCal TOG/TPH Analysers are ideal for soil testing at remediation sites such as leaking underground storage tanks and produced water evaporation ponds. Site managers can obtain on-site measurements and eliminate the need to wait for off-site lab results and save costly down time for remediation equipment.


InfraCal TOG/TPH Analysers are portable (weighing under 5 lbs and operable from a 12 volt power supply)


and read out directly in parts per million (ppm) or mg/kg. Sampling requires a few simple steps and can be performed by non- technical personnel.


Reader Reply Card No. 109 108


The Maya2000 Pro-VIS-NIR fromOcean Optics (Netherlands) is a back-thinned 2D FFT-CCD spectrometer with high sensitivity, 80% peak quantum efficiency and excellent VIS-NIR response. The Maya2000 Pro-VIS-NIR is ideal for low light-level applications such as Raman, as well as for analysis of gases used in semiconductor processing and measurement of biological samples in the life sciences.


The Maya2000 Pro-VIS-NIR has a low-etalon, scientific-grade detector that provides high quantum efficiency from ~400-1100 nm. Other features include triggering functions for providing accurate timing and synchronisation between the spectrometer and other devices.


Three low-jitter trigger modes and normal (free-running spectral acquisition) operating modes are possible. Applications include pulsing a light source when acquiring a spectra and synchronising spectral acquisition to coordinate with samples moving through a process stream or sensors reaching a certain temperature level.


In addition, Maya2000 Pro-VIS-NIR supports RS-232 communications and has a 30-pin connector and 10 user- programmable digital I/Os. Its enhanced onboard programmable high-speed FPGA controller enables triggering and provides other performance advantages.


Reader Reply Card No. 110


Scientific-grade Spectrometer with Enhanced VIS-NIR Response


107


Thermostatically Controlled Cabinets for Sample Storage


Lovibond® thermostatically controlled cabinets from Tintometer (Germany) are used for continuous temperature control over a range of 2°C to 40°C. This makes them ideal for a wide range of different applications in industrial and research laboratories. In particular they are ideal for the temperature-controlled storage of samples or BOD determinations in effluent analysis work.


The temperature can be set in steps of 0.1°C and an LED display shows both the set temperature and the current temperature in the cabinets. Devices such as magnetic agitators, which require a power supply, can be connected to sockets incorporated in the interior of the cabinet. The integral temperature control unit meets the requirements of the EMC directive issued as IEC 61326: "Electrical devices for measurement, monitoring and for use in laboratories".


Lovibond® thermostatically controlled cabinets are available in 4 sizes, with effective capacities from 135 to 395 litres. All models can be fitted with a standard door or a glass door.


Reader Reply Card No. AET Annual Buyers’ Guide 2012 www.envirotech-online.com 111


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