Don't Wait

 Don't Wait
- Automate
June 1997 -- QA/QC

By: Raymond Marsili
Contributing Editor

  Faced with increased laboratory staff downsizing and increased regulatory-testing demands - including the Nutritional Labeling and Education Act and new HACCP regulations - food chemists must work more efficiently now than ever before.  One solution, outsourcing chemical testing, might prove inappropriate in many situations (see "Sending It Out: Outsourcing Pros and Cons," May 1997 Food Product Design). Laboratory automation offers a different productivity-improvement approach that just might provide the edge required by today's analytical laboratories.  Laboratory automation takes many forms. One of the simpler and least expensive concepts - and perhaps the one in existence longest - is the autosampler (also called "autoinjector") carousel for high performance liquid chromatography (HPLC) and gas chromatography (GC) analyses.  Dozens of prepared samples can be loaded into the autosampler carousel. The lab technician then pushes a button, walks away, and returns later to collect results and reload the carousel for additional testing.  These systems allow labs to improve productivity by allowing chemists/technicians to focus their efforts on sample preparation, then load prepared samples into the autosampler where they are chromatographed overnight. This is almost like adding another shift of workers without having to pay labor costs.  In recent years, reliability and robustness of HPLC and GC autosamplers have significantly improved. In addition, most autosamplers no longer require a compressed-gas source in order to actuate values during their operation sequences.  Companies have creatively exploited autosamplers as automation tools for food analyses other than chromatography. The following details noteworthy examples:

Protein analysis: The Kjeldahl technique for protein determination is a time-consuming, relatively dangerous analytical technique. Furthermore, it's difficult and expensive to automate.  Interestingly, because it's so conducive to automation, the Dumas combustion method -abandoned long ago for the Kjeldahl method - is making a comeback in a new and vastly improved form.  One instrument, Leco's FP-2000 protein analyzer (Leco Corporation, Saint Joseph, MI) uses the combustion technique, which offers several advantages: analysis takes only three to four minutes, compared to two to four hours for Kjeldahl; no hazardous-waste generation occurs; cost per analysis ranges from $0.37 to $0.50 (Kjeldahl costs approximately $1 per test); incorporating an autosampler is possible, allowing analysts to run from 23 to 125 samples unattended.  Determination of fat and fat-soluble analytes: Traditionally, Soxhlet methods have determined fat and oil content of solid and semisolid food materials, such as seeds, vegetable materials, snack foods and meats. Today, supercritical fluid extraction (SFE) instruments use supercritical carbon dioxide rather than hot refluxing solvents to extract the fat from these products.  Compared to Soxhlet, SFE generates virtually no organic solvent waste, offers safer operation, and can achieve full automation. Samples can be weighed into extraction thimbles, loaded into an autosampler carousel, and sequentially analyzed without operator attendance. Fats and oils extracted from the food matrix can be collected in a vial, and weighed to determine percent of fat in a sample. Alternatively, extracted lipid material can be further analyzed: it can be saponified, esterified and injected into a GC to determine the amounts of saturated and unsaturated fatty acids in the product for nutrition-labeling purposes.  One company even offers an FTIR interface for on-line SFE-FTIR. SFE-FTIR testing of fats and oils can determine: amount of unsaturated lipids or iodine number; amount of unnatural trans-unsaturated fat formed during partial hydrogenation; and free fatty acid content.  Besides fat analysis, SFE has been used for extracting beta carotene from vegetables, cholesterol from egg powder, pesticides from fruits and vegetables, and flavor compounds from spices. After SFE, the analyte concentration is usually determined by an appropriate chromatographic technique. Determining total fat in animal feed and in snack foods is probably the most-used SFE food application.  Another automated approach to fat analysis that's rapidly gaining favor is ASE (accelerated solvent extraction). One product on the market, Dionex Corp.'s ASE(tm) 2000 (Sunnyvale, CA), can extract 10 grams of solid sample in less than 15 minutes, using only 15 ml of conventional solvent. The technique is safer and more economical than other solvent-based methods, and the instrument can sequentially extract up to 24 samples automatically, using user-specified methods and schedules. Besides fat analysis, the accelerated solvent extraction technique can analyze foods for PCBs, organophosphorous pesticides, and chlorinated pesticides and herbicides. Applications for other food analytes are being investigated.Robo-Chemist  Autosamplers are big time-savers with chromatography instruments and have been used to automate protein analysis, SFE and ASE. But they don't solve all the automation needs of today's food labs.  The time-limiting step in most chemical analyses is sample preparation: the weighing, extracting, filtering, centrifuging, drying and evaporating that usually must be performed before a sample can be injected into an HPLC or a GC. One survey of analytical chemists showed that approximately 61 percent of analysis time is spent on sample preparation, with the remainder divided between data management (27 percent); analysis (6 percent); and collection (5 percent). (Source: R.E. Majors, LC-GC magazine, vol. 9, no. 16, 1991.)  To handle these time-consuming sample preparation chores, more sophisticated automation devices, such as laboratory robotic arms and workstations, are rapidly becoming indispensable laboratory workhorses.  Laboratory robotic systems and workstations now used in modern analytical laboratories bear little resemblance to the anthropomorphic metal robots in '50s and '60s sci-fi films. Today's compact, agile, quick and reliable machines can replace most of the cumbersome, labor-intensive, boring and error-prone sample-preparation steps required in food analysis.  The pharmaceutical and biotechnology industries are driving demand for more sophisticated and reliable laboratory automation instruments. The rapidly growing and highly lucrative drug-discovery field - based on combinatorial chemistry techniques and high throughput screening of thousands of potential drug candidates - could hardly function without today's highly sophisticated laboratory automation techniques.  Laboratory automation has evolved into a workstation concept. These automated, stand-alone units are dedicated to performing certain laboratory tasks: sample-weighing, liquid-dispensing, liquid-handling, and other sample-preparation steps. In general, pipette and sample-vial manipulation is conducted in linear fashion along the x, y or z plane. But robotic arms can grip objects, and maneuver and rotate them in a three-dimensional fashion more like a human arm.  Some workstations can be interfaced to a robotic arm for performing more complex physical manipulations of glassware and reagents. Other workstations incorporate their own dedicated robotic arm. Commonly, robotic arms move vials, flasks or reagents to specific areas of workstations for further processing and manipulation. The arm can be fixed in one spot, where it can reach objects placed around it in a 360° radius, or it can be track-mounted and moved along a linear path to access additional work areas.  Because workstations can be engineered to perform a single, specific function, they are simpler and more reliable devices than robotic arms - and far less expensive. Robotic arms can cost more than $100,000; the tab for workstations ranges between $10,000 and $100,000. Other stand-alone-workstation advantages: They can be operated and maintained by laboratory technicians instead of highly trained robotic/computer experts; and can be designed to provide a data trail for regulatory compliance. Learning to operate workstations requires a far shorter learning curve compared to complicated robotic-arm systems, so productivity gains can be realized almost immediately. In general, workstations are a good choice when only one to three clearly defined manipulations are required. Robotic arms are better for more sophisticated handling needs.Modular approach  A routine QC test might require a dozen or more steps. One efficient, cost-effective approach to automating the process is using two or more workstations, working in tandem. This approach offers not only a less expensive alternative to a single, dedicated robotic-arm-based system, it also is easier to work with and maintain. For example, during an instrument malfunction, only one workstation may be temporarily down. The lab technician can still use the other workstations to automate many of the steps. Also, if the lab's workload changes, and it no longer needs the workstation for automating a certain procedure, it can quickly and easily put the system to work on another procedure that could benefit from automation. Another benefit: If a lab can't afford automating all the steps in one budget year, it can add additional workstations in subsequent years.  In 1969, Mundelein, IL-based Bohdan Inc. - an automated-laboratory-workstation pioneer - started manufacturing automation systems for industrial assembly lines and packaging operations. In the early 1980s, the company expanded into automated systems for pharmaceutical labs. By the mid-1980s, it had developed customized-robotic-arm systems for other laboratory applications. One was for Amoco Research Center, Naperville, IL, to automate its macro Kjeldahl method. Kraft Foods Inc. used a Bohdan system to automate the addition of nitric acid to samples prior to analysis by inductive-coupled-plasma analysis, and to perform automated fat analysis by the Mojonnier method. Today, Kraft's Glenview Technology Center, Glenview, IL, uses two robots to perform fat analysis, as well as additional automated systems for performing vitamin assays and inductive-coupled-plasma analysis.  "We developed the workstation concept by listening to what customers had to say about what they didn't like about the laboratory automation systems that were on the market," says Lauren Wagner, Bohdan's vice president of sales and marketing. The complaints: Bulky robotic-arm systems were too costly, too complicated, and took up too much valuable counter top space. Bohdan responded by developing the compact and flexible workstation concept.  Companies should remember they don't have to automate all the steps in an analytical procedure to be effective, Wagner says. To completely automate a complicated test procedure with a complex automation system could be cost-prohibitive. Usually, one or two tasks can be difficult and expensive to automate. But there are probably several time-consuming, error-prone steps in the procedure that can be economically automated. So, automate these steps with one or more less-expensive workstations. "With this approach," Wagner says, "you can get the productivity gains you need without wasting a lot of money."Beyond speed and efficiency  Laboratory automation usually results in other benefits besides labor savings and productivity improvements. Able to automatically record and store sample-weight measurements directly from an analytical balance, and with bar coders recording and tracking sample identification, workstations don't make the bookkeeping and transcription errors weary lab personnel sometimes make. In addition, because laboratory automation devices can replicate injection and sample-preparation techniques more consistently than humans, their analytical results are frequently more precise and accurate than those obtained using manual techniques.  Automation also provides a positive effect on lab personnel. Most lab managers report considerable morale improvements when chemists and technicians are freed from routine, monotonous tasks. They can devote more time to important, challenging functions and can focus on areas where they can improve company results- such as problem-solving.Laboratory Automation:
Not Just for Analytical Chemists  Not only analytical chemists and technicians utilize automated liquid handling/diluting instruments to improve work efficiency. Food product designers also may benefit from the application of automated laboratory systems. Consider the labor-intensive task of flavor-compounding in food and beverage manufacturing.  Often, many ingredients - some quite expensive - are required to create the desired flavor. And, the creation process requires many small-scale samples to be prepared for analysis and evaluation. The challenge is to prepare these small samples with complete accuracy and consistency.  A flavorist for a major soft drink company on the East Coast faced just such a challenge. Pressured by short development cycles and limited project turnaround time, flavor development was sometimes compromised. The time required to prepare samples manually limited the opportunity to evaluate and optimize the flavor. Inaccurate weighing of ingredients, omission of one or more ingredients, and similar errors in manual liquid-handling procedures also caused problems.  Replacing manual flavor-formulating with an automated system provided the following benefits: It gave the flavorist virtually unlimited options for collection volume and capacity. Accuracy was now assured because human error had been eliminated. The automated liquid handler didn't skip ingredients, and it treated every sample identically for totally reproducible results. Flavor formulations could be stored in a computer and quickly downloaded to the automated liquid handler when required. Since tedious, time-consuming steps had been eliminated, the flavorist had more time for creating and optimizing flavor formulations.  For this soft drink flavorist, automation in the R&D lab resulted in high throughput, improved precision, increased creative productivity, and decreased labor costs.Titration Elation  Titrations still comprise a significant part of most food labs' workload. Instrument manufacturers now offer reliable automated titration systems with truly remarkable features. One example: Westbury, NY-based Brinkmann Instruments. Like Bohdan's workstations, which offer a systems approach to automation, Brinkmann's Metrohm approach to sample and data management can be conveniently customized to meet a food lab's specific work demand. Various stages of automation can be added over time to accommodate lab budgets and workload demand.  These titrators can handle all, or any part of the steps in the process - from sample weighing, to data calculation and report generation. Numerous add-ons can be made, including a printer, bar-code reader, sample changer, or sample manipulator. The instrument can be connected to a personal computer with Brinkmann Workcell(tm) Titration Software, a Windows(r) 95 or NT 4.0 application, and then to a LIMS (laboratory information management system).  The Metrohm Titration Manipulator manages up to 104 samples automatically, measuring the liquid sample and transferring it to a titration vessel. Precise liquid metering of sample, from microliters to milliliters, is easily accomplished. It also can evaluate all end points, measure pH and conductivity, and raise the liquid surface sensor and the pipette tip to prevent cross-contamination.  The company's Sample Changers can add reagents and solvent; clean electrodes (by dipping into a cleaning solution or by spraying with a cleaning mist); and perform many other functions.  Typical food lab QC tests performed by Brinkmann's autotitrator include: hardness and chloride in processing water; salt and titratable acidity of pickle products; vinegar in mayonnaise; titratable acidity in wine or fruit juice; Kjeldahl nitrogen; sulfur dioxide in wine.  "Several beverage companies, including many Pepsi bottlers, are using our automated systems to make at-line determination of vitamin C (by the iodometry) and total acidity," says Larry Taylor, Brinkmann's director of marketing.  Another food lab QC test procedure, of interest to confectionery companies, is an automated Karl Fischer titration for water determination in hard candies. "This has been a demanding test to perform in the past," Taylor says. "But by combining the Karl Fisher Titrator with a Brinkmann Polytron homogenizer, which rapidly extracts the moisture from the hard candy into methanol solvent, the test can be accurately performed in record time with a minimum effort from the lab technician."  This technique offers greater accuracy than gravimetric-oven-drying methods, which may pull off volatiles other than water, according to Taylor. It also uses less solvent than other moisture-determination techniques.Company ContactsBohdan Automation Inc.
1500 McCormick Blvd.
Mundelein, IL 60060
847/680-3939Cyberlab, Inc.
36 Del Mar Dr.
Brookfield, CT 06804
800/292-3752Gilson, Inc.
3000 W. Beltline Hwy.
P.O. Box 62007
Middleton, WI 53562-0027
800/445-7661Hamilton Company
4970 Energy Way
Reno, NV 89502
800/648-5950Leco Corporation
3000 Lakeview Ave.
Saint Joseph, MI 49085
616/982-5496Sagian, Inc.
P.O. Box 68356
Indianapolis, IN 46268
800/352-4975SciLog
14 Ellis Potter Ct.
Madison, WI 53711-2478
800/955-1993Source for Automation
327 Fiske St.
Holliston, MA 01746
508/429-3377Zymark Corporation
Zymark Center
Hopkinton, MA 01748-1668
508/435-9500Back to top