On the safe side with MCERTS accreditation
Online TOC-4200 reveals its strengths during field tests
Shimadzu’s online TOC-4200 analyzer has been granted MCERTS accreditation based on the performance standards and test procedures set for continuous water monitoring equipment.
MCERTS is the certification system of the Environmental Agency of England and Wales (UK) for measurement equipment. It provides the framework conditions and quality objectives for companies to meet in order to comply with the authority requirements for environmental monitoring.
MCERTS is quickly becoming a required performance and reliability standard by organizations around the world. With accredited equipment, companies and authorities ensure that they are doing everything possible to protect their environment. Requirements for obtaining this certification include laboratory testing and a 3-month field test under real conditions.
The TOC-4200 is a powerful analyzer that is operated under catalytic combustion at 680 °C. The analyzer removes the inorganic carbon content automatically from the sample and subsequently injects an aliquot onto a 680 °C hot platinum catalyst where all organic compounds are oxidized to carbon dioxide.
The resulting CO2 is transferred by a carrier gas stream to a highly sensitive and CO2-selective NDIR detector where it is measured. The TOC concentration is calculated using an external calibration. The integrated dilution function allows TOC analyses up to 20,000 mg/L. In addition, it allows automated dilution of the sample when the measurement range is exceeded.
The automated dilution as well as the self-calibration functions and the optimized sampling allow a virtually independent operation of the measurement system.
Numerous alarm and status signals simplify the detection of exceeded limit values or the need for maintenance. In addition to the conventional options, Modbus communication is also available. An optional web browser enables a “view” of the instrument from any networked computer.
The TOC-4200 performance data, such as the mean measurement error, linearity and reproducibility were determined in laboratory tests. For this purpose, the TOC-4200 was installed in the laboratory and calibrated as a function of the measurement ranges. Subsequently, five measurement points were measured six times each: 10, 25, 50, 75 and 100 % of the respective measurement range.
Table 1: Results for the measurement range 0 – 100 mg/L
For the determination of the mean measurement deviation, the mean deviation from the reference value was calculated for each measurement point. The highest value is listed in the certification report. To pass the test, this value must be less than 10 %.
The mean deviation for the measurement range 0-100 mg/L is 1.99 %. The test for this range was therefore passed. For the linearity determination, a linear plot was determined from the mean values of the measurement points. The deviation of the measured data from the straight line was subsequently calculated in %. The maximum value may not exceed 5 %.
Table 2: Mean error in %
For the measurement range 0-100 mg/L, the linearity is -2.23 %, which meets the test requirements for this range. For the reproducibility, the standard deviation and the relative standard deviation were calculated from the measured data of each measurement point. Again, the highest value may not exceed 5 %.
Table 3: Linearity
The reproducibility for the 0-100 mg/L measurement range is 0.93 %. The test for this range was therefore passed. Measurements were also carried out for the measurement ranges 0-500 mg/L, 0-1.000 mg/L and 0-10,000 mg/L. All values obtained were below the specified limits. In addition, data were obtained to determine drift, matrix influence and response time.
Table 4: Reproducibility
For the field test, data collected over three months from a customer installation in a wastewater application (measurement range 0 to 100 mg/L) was evaluated. Particular attention was paid to operating time and downtime. Downtime includes time for calibration, maintenance, service and troubleshooting. The resulting availability should be higher than 95 %. The TOC-4200 reached 100 %.
Conclusion – unique TOC on the market
The TOC-4200 achieved a 100 % availability in the field test, highlighting its robustness and reliability. It is the only online TOC analyzer utilizing catalytic combustion oxidation available on the market with MCERTS accreditation. This technology offers a clear advantage for anyone involved in the analysis of water and wastewater with a high salt content, solids or suspended matter as well as complex organic compounds.
The certificate (MC160311/00) was issued for the TOC measurement ranges 0-100, 0-500, 0-1.000 and 0-10,000 mg/L.