For continuous mode, we recommend a minimum of 600 mL for a sample. For GC Emulation Mode, the minimum sample volume is 15 mL, but this mode is not as sensitive to low levels of ethylene. The lower detection limit of the F-900 is 40 ppb, or 0.040 ppm when used in Continuous Monitoring Mode. In GC Emulation Mode, the lower detection limit is 0.800 ppm with a range of 0.800 ppm to 20 ppm.
In Continuous monitoring mode, gas enters through the inlet of the device and is drawn in by the pump. The inlet can be free of tubing, in which case it will measure ambient air, or it can be connected by tubing to a chamber or other measurement location or apparatus. In GC Emulation Mode samples are injected into a special port that connects to both the inlet and outlet of the device.
The device will automatically switch between the PPB and PPM level ethylene sensors depending on the measurement level that it is currently reading and the slope of the change in reading. The automatic switching threshold is about 2.5 ppm. Each sensor can also be manually shut off prior to measurement.
There are common, everyday sources of ethylene that can be picked up on by the sensors in your Felix Gas Analyzers. Common sources of ethylene include smoke or exhaust. Furthermore, the ethylene sensors inside of the Felix Gas Analyzers are also sensitive to various volatile organic compounds (VOCs). Various cleaning agents are often a source of VOC readings. If you are inside, it is not uncommon for the ethylene sensors to report readings between 0-0.5ppm of ethylene. If you are outside, drawing clean ambient air (away from traffic, smoke, or other sources of exhaust) it is more typical to see 0.0 ppm readings for ethylene.
The 16GB card provided with the F-9xx gas analyzers technically has indefinite storage capacity as the files can be moved off the card to reopen storage space. However, without moving any files off the card, it can hold up to ~60 million measurements from a F-9xx analyzer. If the instrument is saving data every minute that equates to ~40,000 days of measurement before the SD card is full.
I don’t feel that my F-9xx Gas Analyzer is reading accurately, what should I do?
When communicating with support it is helpful to provide:
If your analyzer is less than three months old, see the two options below:
Perform a set zero calibration on the sensors using the external conditioning chamber filled with potassium permanganate for the ethylene sensor and the external conditioning chamber filled with soda lime for the CO2 sensor. Use the O2 calibration in air menu option to calibrate the O2 sensor using ambient air. Only use the O2 set zero setting if you are using 100% nitrogen gas.
Please see the user manual for more details.
If your analyzer is over three months old, see options below:
If your instrument is over three months of age, inaccurate sensor readings could indicate a need for calibration. You can try a baseline calibration (or set zero) of the sensors first and if this does not bring the readings into spec, then perform a full calibration.
Please see ‘How Do I Calibrate the Instrument?’ FAQ for more details.
Note: Due to limitations of Microsoft Translate, manuals greater than 50 pages in length currently do not support dynamic translation.
First, we need to set the internal volume of the unit in accordance to which sensors are present.
Next, we will calibrate the unit using the following formula:
Calibrated Volume = (Sample concentration * Sample volume) / GC Emulation Result
**Please note that it is absolutely imperative that the analyzer have all sensors properly calibrated before continuing.**
The electrode is platinum with a lead-based counter-electrode.
The electrochemical sensor uses a nafion or nafion-like membrane.
Both are portable, but the research kit includes the other components shown on the website, such as the fruit chamber and wand and hard-sided carrying case. The Research Kit is designed to make measurement of fruits on a tree (non-destructively) more convenient. A fan is built into the chamber to mix the air around the fruit.
Climacteric fruits refer to fruits that have high respiration rate during the fruit's ripening. During the ripening process of climacteric fruits, the production of a phytohormone, ethylene, dramatically increases up to 1000-fold of the basal ethylene level. Climacteric fruits are ones that are able to ripen after being picked. An example of climacteric fruit is bananas; they are picked and shipped green and then ripen at a later time (often in the store or home). Climacteric fruits include, but are not limited to, apples, apricots, avocados, bananas, cantaloupes, figs, guavas, kiwis, mangoes, nectarines, peaches, pears, persimmons, plums, and tomatoes. [Source: Wikepedia.com]
If data isn't displaying properly, try saving the file as a .csv file type and re-opening it. If saving as a .csv does not fix how the data is displayed, you may need to change the separator value on your computer.
To change the separator in all .csv text files:
NOTE: After you change the list separator character for your computer, all programs use the new character as a list separator. You can change the character back to the default character by following the same procedure.
Several types of material have been found to outgas interfering gases of the ethylene sensor, such as Tygon. Viton and Teflon have successfully been found to not outgas.
If the cell runs out of water, the lead electrode could undergo sulfation. This would affect the sensitivity by reducing the active area on the lead electrodes. It is more likely that a lack of water in the cell decreases the activity of the electrolyte and increases the resistivity of the Nafion membrane. Both will affect the background current and response time of the cell.
Using Polarcept (patented) can help keep the electrochemical cell hydrated.
The electrochemical sensor can be rehydrated by putting distilled water in Chamber In. If water is being used in Chamber In for separating out alcohols, then refilling of the sensor will never be necessary. Similarly, if the sensor is used in a humid environment, the sensor will not dry out.
The temperature and relative humidity sensor is located inside the F-900, before the electrochemical sensor. There is an additional relative humidity sensor after the ethylene sensor to help track water loss.
Both chambers are optional, but it is recommended to use Chamber In as PolarCept for most measurements. The most common use for Chamber In is to separate light hydrocarbons, such as alcohol, from the gas stream which may interfere with the measurement. The most common use for Chamber Out is to be filled with potassium permanganate, so that it cleans all ethylene and other hydrocarbons from the gas stream, so that any ethylene that is measured must have come from the sample. Chamber OUT is also commonly used with KMnO4 to calibrate the zero of the ethylene sensors.
There is a protective hydrophobic filter inside the IN port on the front of the F-900. This will prevent moisture from fully entering the instrument. Silica gel in a conditioning chamber can be used to dry out the gas stream, either before or after the gas passes the electrochemical sensor. Refer to the flow path diagram in the Setup>Chamber section of the User Manual for more information.
1-MCP is short for 1-Methylcyclopropene. This is a synthetic plant growth regulator, which is structurally related to ethylene (natural plant hormone). When applied to fruit, 1-MCP binds to ethylene receptors without triggering the signal cascade that leads to climacteric ethylene biosynthesis and ripening. Commercially, it is used to slow down the ripening of fruit and to maintain the freshness of cut flowers. The chemical formula is C4H6.
To start using the F-900, you need to create a file to save data into. Go to File<Create. Change the file00 to the desired file-name and press save. Next, open the file to save measurements. Go to File<Open and use the arrows to highlight the newly created file. If the value next to the file-name is a negative number, this indicates an error. You should delete the file and create it again. Then, open it and check that the value is zero. Now, you can save data into this file.