In-house Quality Control Research Articles

Sensory based quality control utilising an electronic nose and GC-MS analyses to predict end-product quality from raw materials

The objective of the present study was to investigate if an electronic nose, comprising six metal oxide sensors (MOS) could predict the sensory quality of porcine meat loaf, based on measuring the volatiles in either the raw materials or the meat loaf produced from those raw materials. A multivariate data analysis strategy involving analysis of variance partial least squares regression (APLSR) and principal component analysis (PCA) was used to determine causal and predictive relationships between the raw material and meat loaf samples, sensory analysis, electronic nose, and GC-MS measurements. The results showed that the six MOS sensors in the Danish odour sensor system (DOSS) could detect the raw materials that led to unacceptable products, as determined by sensory profiling and in-house sensory quality control (QC), and separate those raw materials from each other, based on the volatile composition, as determined by GC-MS. However, the electronic nose was unable to detect all the sensory unacceptable meat loaf samples themselves due to changes in the volatile composition after cooking. Analysis of the GC-MS compounds identified from raw materials and meat loaf samples indicate that two MOS sensors mainly responded to alcohols and to a lesser degree to aldehydes and alkanes, whereas two other sensors most likely responded to low molecular weight sulphur compounds. Thus, the results indicate that measuring volatiles with the MOS sensors in the DOSS system, on raw materials for processed meat products, may be a feasible strategy in sensory based quality control, and may also have potential in predicting the sensory quality of the end product.

Development of Test Method for Determining Plasterboard Bracing Performance

The Australian Residential Timber-Framed Construction standard (AS1684:1999) has recently been revised to explicitly define the bracing contribution of nominally fixed plasterboard clad walls as 0.45 kN/m for cladding on one side and 0.75 kN/m for cladding on two sides. These values clarify the allowance, which designers may rely upon for the presence of plasterboard and their inclusion in the standard infers a necessity for plasterboard products to at least meet these requirements. A review of the relevant Australian, ISO, and ASTM standards, as well as plasterboard manufacturers’ in-house quality control tests has established that these tests mainly focus on serviceability aspect of plasterboard (e.g., storage, transportation, and installation) rather than that of structural bracing performance. It has also been determined that there are no direct correlations between serviceability conditions and structural bracing performance of plasterboard. In fact, a limited set of data provided by the plasterboard manufacturers shows that almost no correlation exists between the current quality control tests and the most commonly measured parameter, the density of plasterboard. It has been concluded that current tests are inadequate to serve as control measures for bracing performance of plasterboard. Nonetheless, it must be noted that density is not the only parameter that may influence the bracing performance of plasterboard; other parameters such as linerboard strength and bonding between gypsum and linerboard may also affect the bracing capacity. This paper details a new test, termed fastener bearing test, which provides a method to evaluate the bracing capacity of plasterboard. The results of this test show a very high correlation with shear connection tests. The proposed test is practical and simple to perform as part of the manufacturing process, in addition to the current tests, without severe cost and time penalty to the plasterboard manufacturers.

Arsenic Species Determination in Biological Tissues by HPLC - ICP - MS and HPLC - HG - ICP - MS

The use of high-pressure liquid chromatography coupled directly or by a hydride generation system to an inductively coupled plasma mass spectrometer for the unambiguous measurement of 13 arsenic species in marine biological extracts is described. The use of two chromatography systems; a Supelcosil LC-SCX cation-exchange column eluted with a 20 mM pyridine mobile phase adjusted to pH 2.2 and 2.6 with formic acid, with a flow rate of 1.5 mL min−1 at 40°C, and a Hamilton PRP-X100 anion-exchange column eluted with 20 mM NH4H2PO4 buffer at pH 5.6, with a flow rate of 1.5 mL min−1 at 40°C, was required to separate and quantify cation and anion arsenic species. Under these conditions, arsenous acid could not be separated from other arsenic species and required the use of an additional hydride generation step. Arsenic species concentrations in a locally available Tasmanian kelp (Durvillea potatorum), a certified reference material (DORM-2), and a range of commercially available macroalgae supplements and sushi seaweeds have been measured and are provided for use as in-house quality control samples to assess the effectiveness of sample preparation, extraction, and measurement techniques.

Predicting the mechanical properties and retained austenite content of ADI castings using non-destructive testing techniques

Mechanical testing is expensive, labour intensive and only provides properties of sacrificial castings or representative test bars but offers no guarantees about other castings from the same batch. X-ray diffraction for determining retained austenite is slow in terms of sample preparation and testing and is not suitable for routine use. Hence the ability to predict mechanical properties and retained austenite contents of ADI castings by a rapid shop floor non destructive technique would improve in-house quality control and provide a means of evaluating every casting before despatch.By combining multi-frequency eddy current data with ultrasonic velocity or resonant frequency measurements, clear relationships with 0.2% proof strength and tensile strength have been demonstrated. The best predictions of 0.2% proof and tensile strength for commercially produced ADI castings were better than±12% of measured values providing algorithms were derived using material having a similar composition and heat treatment. Under the same conditions the volume fraction of retained austenite in commercially produced ADI castings was predicted with an accuracy of better than ±0.04. An encircling eddy current coil is more sensitive than a probe and has slightly improved predictive accuracies.

Rapid in-house quality control using C-18 (Sep-Pak) reverse-phase chromatography cartridges verifies that 99Tcm-MAG3 is stable for at least 8 h

Rapid in-house quality control using C-18 (Sep-Pak) reverse-phase chromatography cartridges verifies that 99Tcm-MAG3 is stable for at least 8 h

NIST MQA for environmental radioactivity measurements

The Ionizing Radiation Division of the National Institute of Standards and Technology (NIST) has implemented several quality assurance programs to provide a consistent basis for environmental-level national and international ionizing radiation measurement credibility and comparability. These programs cut across a variety of sectors that include: (1) personnel protection; (2) survey-instrument calibration; (3) environmental radiochemistry and (4) radiobioassay. The four basic elements of the MQA programs are: (1) conformance to promulgated consensus criteria; (2) documented inhouse quality assurance and control practice; (3) periodic performance evaluations using appropriate testing materials and instruments; and (4) periodic on-site assessments by technical experts. The periodic performance evaluations are important for the demonstration of measurement traceability to the national and international physical standards. Traceability testing, however, must be augmented by the other elements to provide the strongest rationale for measurement assurance. This paper will describe the NIST programs and future directions for new programs.

Simple Method for the Accurate Determination of Selenium in Serum by Using Inductively Coupled Plasma Mass Spectrometry

A simple 1+15 dilution of 200 µl volumes of serum with a diluent containing 1.0% v/v butan-l-ol; 0.66% Triton X-100; 0.01 mol l -1 NH 3 , 0.0002 mol l -1 (NH 4 ) 2 H 2 EDTA and 0.002 mol l -1 NH 4 H 2 PO 4 enables ICP-MS to provide accurate and precise measurements of total selenium concentrations. Interferences from argon-adduct ions on selenium isotopes 77 Se, 78 Se are eliminated and are considerably reduced at 82 Se by the presence in the diluent of butan-l-ol. The other reagents prevent blockage of the torch injector tube during prolonged, ≥6 h, analytical runs. The detection limit (3 s blank) is 0.02 µmol l -1 (1.5 µg l -1 ) and within-run RSDs range from 3.4 to 7.5% at 0.3 µmol l -1 , to 1.5 to 2.0% at 2.1 µmol l -1 . Analyses of 12 sera from an external quality assessment program, of a commercially available reference serum material (Nycomed) and of in-house internal quality control sera gave excellent agreements with median/target concentrations over the range 0.3 to 3.3 µmol l -1 . The ICP-MS data showed small, but acceptable, negative biasses at 1.0 µmol l -1 of: -3.8% and -5.0% at 77 Se and 78 Se, respectively.

Dilution potential: a new perspective.

The objective of this work was to develop a method to assess the dilution capacity of direct compression excipients based on a technique previously proposed by Minchom and Armstrong (MA). The technique involves the addition of increasing quantities of a poorly compactible (compressible) material to the excipient and measuring the resultant decrease in the AUC of the tensile strength versus compaction force profiles. The AUC of each mixture is divided by the AUC of the "0% mixture" to obtain MA's "work potential," called "area ratios" in the present study. The applicability of this approach was tested using three excipients differing in their deformation mechanisms: microcrystalline cellulose (Avicel PH 101, 102, 200, 301, 302) representing a plastic material; dibasic calcium phosphate (Cal-Star) representing a brittle material, and anhydrous lactose, which exhibits both brittle and plastic properties. Ascorbic acid or acetaminophen was the poorly compactible challenge material. In the first study, the MA method was found to apply only to Avicel PH 101, since the area ratios for mixtures containing different compositions of acetaminophen with either Cal-Star or anhydrous lactose remain constant until a certain percentage of drug is exceeded, after which a decline starts to be observed. Further work carried out on mixtures of different grades of Avicel with ascorbic acid revealed that MA's approach reflects only the ability of the excipient to handle internal stress induced by the drug and does not take into account the intrinsic ability of the drug-free excipient to form strong compacts. A new index was thus proposed, called the dilution capacity index (DCI), which weights the MA index by the AUC of the drug-free excipient. The results suggest that DCI can be used to compare different grades of microcrystalline cellulose and provide in-house quality control for microcrystalline cellulose suppliers.

Wound infection: the surgeon's responsibility.

Surgical audit has two main purposes: the pursuit of efficiency through the review of clinical workload and the pursuit of quality by reviewing clinical outcomes. In-house quality control is an important aspect of surgical practice. This prospective study aimed to determine the incidence of infection, describe the time distribution of presentation and identify contributory factors. There were 1 242 consecutive patients in the survey (1 086 inpatients and 156 day cases), of whom 83 became infected (79 in-patients and four day cases) - an overall infection rate of 6.7%. Over 55% presented during the first week and 89% within the first two weeks. Of 23 specific aetiological variables studied, four - age, preoperative stay, shaving and the surgeon - were shown to have a statistically significant association with the development of wound infection. A strong association between the surgeon and the development of wound infection was demonstrated. In addition to obvious strong resource implications, it supports the need for routine audit supervision and training of junior staff and peer review for senior clinicians.

Two-site in-house quality control for estrogen receptor (ER) assay

As no external Quality Control Program has existed for ER assay since 1988, and commercial preparations are either unsuitable or expensive, a local QC program was set up between our hospitals. An ovarian tumour with high levels of ER was obtained. Cytosol was prepared, aliquoted into Nunc cryotubes and stored at -70°C. This material has been used in each ER assay (Abbott ER-EIA) at both the hospitals since January 1989. Mean cytosol ER values have not changed significantly over a 2.5 year period (see table). The difference in results between the laboratories was primarily due to different methods of proteins estimation. Mean intra-assay coefficients of variation (CV) were 2.1% and 4.8% for RWH and RMH respectively.RWHRMHNMEANSDCVNMEANSDCV1989 RESULTS378513154011728241990 RESULTS409918173810820181991 RESULTS19105131324140139.4 The cytosol preparation, although stable when frozen, was quite heat labile. It showed partial loss of activity after 10 minutes at room temperature, and total loss of activity after 30 minutes at 37°C. If stored at -70°C, it remains stable over at least two years, and provides a suitable cheap source of QC material. It, however, does not address the issue of inter-hospital error introduced in the homogenisation process.

Peroperative anaesthetic audit

The need for audit of operating theatre work is clear, both from an ethical and a medicolegal standpoint--'in-house quality control is an important aspect of clinical practice' (Lunn and Devlin, 1987). The problem is to know what to record, and how to record it so that it will be both acceptable and worthwhile to working anaesthetists. The first report of the audit committee of the College of Anaesthetists (November 1989) suggested the use of logbooks to make a personal record for all anaesthetists, together with a record of departmental theatre service load, work in other areas such as the intensive care unit, morbidity and mortality audit, a critical incident register and education audit. We have been recording departmental and individual theatre service load for three years. At first, we attempted to record every fact about the anaesthetic to form a complete anaesthetic record so that no data would be lost. There are many variations on this theme: Cardiff (Lunn and Vickers, 1982), Glasgow (Todd et al, 1983), Harvard (McPeek, 1980) and others have collected large databases and distilled essential information from them. For example, at Cardiff (Farrow et al, 1984) and Cleveland (Schneider et al, 1979) it has been shown how one could begin to predict anaesthetic risk factors and hospital morbidity. This sort of work, however, requires substantial resources of manpower and funds which are seldom available. Moreover, when these data were considered more closely, the vast majority was of little use to a district hospital, where it is not generally necessary to collect information about drug and disease type during anaesthesia since this information is already available as part of the patient administration system or from the pharmacy computer. Computerizing the anaesthetic record was not part of our task. We had thus to define our requirement more clearly. It was to develop a system that could be used by an anaesthetic department to provide the peroperative data needed for audit and management on a daily routine basis. Information should be derived that would provide answers to the sorts of questions being asked by the College Visitors when reviewing a department, or by managers looking at working patterns. There should be in addition some record of the complications arising during anaesthesia. The system should use a standard software package, running on standard equipment that can be bought 'off the shelf', so that both can be used by the department for other purposes during the time that it is not processing data,

In-house biological trace element quality control materials

In-house biological trace element quality control materials

Hyperthermia quality assurance guidelines

These Hyperthermia Quality Assurance guidelines are a result of a joint workshop of the Hyperthermia Committee of the American College of Radiology and the Hyperthermia Physics Center, which is the national quality assurance program under Contract No. N01-CM-37512 with the National Cancer Institute. Hyperthermia technology presently the kind of standardization in equipment, treatment procedures, patient monitoring, and treatment documentation available in radiotherapy. Therefore, preventing unacceptable variability in treatment data demands a strong commitment to in-house quality control procedures and to centralized quality assurance reviews in cooperative multi-institutional trials. This paper presents a set of test procedures necessary to ensure proper operation of equipment, suggests a frequency for such tests, and also includes guidelines on quality control procedures to be used during treatment to improve the safety, effectiveness, and reproducibility of hyperthermia treatments. A set of forms are presented to indicate the minimum data, albeit incomplete, that must be collected for acceptable documentation of treatment. These guidelines should be valuable not only to the new entrants in the field but also to those participating in multi-institutional cooperative hyperthermia trials. They have been approved by the Hyperthermia Committees of American College of Radiology, American Society for Therapeutic Radiology and Oncology, Radiation Therapy Oncology Group and the American Association of Physicists in Medicine.

Round Robin Fire Safety Tests on Cellulose Insulation Testing Program: Round 2

This paper describes the California Bureau of Home Furmshmgs - Insulation Pro gram round robin fire safety, second round testing results for Cellulose Insulation material. The results of the California Bureau of Home Furnishings proficiency test ing program from manufacturer's in-house quality control testing laboratories and other National Voluntary Laboratory Accreditation Program (NVLAP) accredited laboratories are given. Tables show the statistical results of data submitted by partici pating laboratories for critical radiant flux and smoldering combustion.

Computation of In-house Quality Control Limits for Pharmaceutical Dosage Forms Based on Product Variability

□ A method for establishing sampling plans for in-house limits that fix both the producer’s and consumer’s risks is presented for pharmaceutical systems in which both between-batch and within-batch variations are present. Such plans can always be constructed and require more or less sample assays depending on the variability of the process. The computations involve a numerical approximation to the bivariate normal distribution.

A pragmatic approach to the particle sizing of submicrometre emulsions using a laser nephelometer

The use of a commercial laser nephelometer to measure the mean particle size of submicrometre emulsions is described. The instrument is sufficiently sensitive to measure particles smaller than 600 nm. The method is comparative, and two standard materials of known size that are physically and chemically similar to the test emulsion must be used. The method is rapid and inexpensive, and may be used as a routine, in-house quality control procedure for monitoring emulsion production processes such as homogenization. However, it is only suitable if the average particle size of the system is smaller than 600 nm and, probably, with a relatively narrow size distribution.