Featured Article
Natural cork is the seal of choice for fine wine manufacturers. Its composition provides a unique blend of oxygen and phenolic compounds, which allows wines to age correctly. Cork is also naturally elastic, ensuring a secure, inviolable seal. With alternative artificial seals, such as synthetic stoppers or aluminum screw caps, oxidation and reduction of the wine can occur. Bottle stoppers are usually considered to be responsible if any wine faults (undesirable smells or tastes found in a bottle of wine) occur.
Despite cork’s remarkable qualities, it is prone to the naturally occurring chemical analyte TCA. Corks containing high levels of TCA can cause cork taint, contributing to wine faults and thus negatively impacting revenues. The ability of cork producers and wine manufacturers to guarantee TCA-free cork therefore has obvious benefits. Ellutia (Cambridgeshire, U.K.) developed a solution for a manufacturer of natural corks that guarantees nondetectable TCA. A nondetectable TCA guarantee means that if any TCA remains in a cork, it is below the detection threshold of 0.5 ng/L.
Requirements
Because standard gas chromatography examination of corks can take up to 14 minutes, it is not feasible for use on production lines. The cork producer was using GC in laboratory-controlled batch testing as part of its quality-control measures for the 40 million corks it produces annually. These measures meant that only small numbers of the corks had been tested, and always after production. The company needed to improve the technology so that 1) each individual cork on the line could be tested, and 2) natural corks could be analyzed for TCA in seconds.
Developing the technology
Ellutia designed a custom analyzer based on a 200 series GC. It tests each wine cork on the production line for TCA using fast chromatography technology developed by Ellutia and the cork producer. The prototype detected 10 ng/L of TCA, equivalent to the cork manufacturer’s current testing methodology. After redesigning the prototype for use on the production line, TCA detection limits were increased to an unprecedented 5 ng/L. The custom analyzer employed off-the-shelf columns from a chromatography consumables manufacturer.
Challenges and solution
Ellutia supplied these analyzers to its customer in Portugal. While all of the analytical challenges were met, there was room for improvement. The original systems used metal columns sourced from the columns manufacturer via its U.K. distributor. Preventative maintenance was now required for the analyzers, and 240 new columns were needed as soon as possible. However, the supplier could only commit to delivery in 8–10 weeks. Further, the columns they offered were tied with metal banding that was not suitable for the cork analyzer without modification. This meant manually unwinding each column and recoiling and banding, which would add considerable time to an already urgent replacement schedule.
Clearly, this supply challenge needed to be addressed, and for this Ellutia approached Agilent Technologies (Santa Clara, CA). Agilent reviewed the column specifications, including the dimensions of the coil and banding, and proposed a customized solution. According to Dr. Mark Landon, technical director at Ellutia, “Agilent was able to make the units to our specifications—they can now be bought and installed straight away. We required over 100 units—a batch from our original supplier would have taken 8–10 weeks—sourcing from Agilent would only take three weeks to delivery from placing the order—this time frame included customization.” He added that these delivery improvements did not account for the time saved by the Ellutia team (rebanding was not necessary with the Agilent column). Agilent committed to deliver in batches of 48 columns (6 × 8) every three weeks at the required specifications and dimensions and at a more competitive price. The initial shipment of 232 columns was delivered to Ellutia’s customer.
System improvements
The original system operated with waste columns from a different supplier. If all columns do not work to the same level and standard, the peak will vary due to different gas flows and pressures. With the new system, all eight columns (analytical and waste) were from the same manufacturer. Using one brand of columns throughout the production cycle made system set-up quick and easy, with fewer parts needing to be purchased.
Ellutia’s fast chromatography system can analyze each cork on its customer production line in seconds—a dramatic improvement over previous testing that typically required up to 14 minutes per batch. The custom analyzer can detect any cork with more than 0.5 ng of TCA per liter (parts per trillion). This detection threshold is the equivalent of one drop of water in 800 Olympic-size swimming pools. The analyzer will be used in conjunction with existing preventive and quality control measures, including patented treatments used during production. As a result, all corks processed via the analyzer are nondetectable TCA guaranteed, and analysis is performed in accordance with ISO 20752. Up to now, no cork producer has been able to guarantee an automated quality control system for natural cork stoppers that screens individually.
Dr. Robert Bunn is manager, Strategic Transactions, Agilent Technologies, Inc., 5301 Stevens Creek Blvd., Santa Clara, CA 95051, U.S.A.; https://www.agilent.com/home/more-countries?currPageURL=http://www.agilent.com/home. Andrew James is marketing director, Ellutia, Cambridgeshire, U.K.